diff --git a/frontend/app/adapters/activity-block.js b/frontend/app/adapters/activity-block.ts
similarity index 86%
rename from frontend/app/adapters/activity-block.js
rename to frontend/app/adapters/activity-block.ts
index 84f076928..8ae348561 100644
--- a/frontend/app/adapters/activity-block.js
+++ b/frontend/app/adapters/activity-block.ts
@@ -41,3 +41,9 @@ export default class ActivityBlockAdapter extends ApplicationAdapter {
     return `${super.urlForCreateRecord(...args)}?include=activity`;
   }
 }
+
+declare module "ember-data/types/registries/adapter" {
+  export default interface AdapterRegistry {
+    "activity-block": ActivityBlockAdapter;
+  }
+}
diff --git a/frontend/app/adapters/application.js b/frontend/app/adapters/application.ts
similarity index 100%
rename from frontend/app/adapters/application.js
rename to frontend/app/adapters/application.ts
diff --git a/frontend/app/config/environment.d.ts b/frontend/app/config/environment.d.ts
index 131cb0a93..be4017478 100644
--- a/frontend/app/config/environment.d.ts
+++ b/frontend/app/config/environment.d.ts
@@ -6,9 +6,9 @@ declare const config: {
   environment: string;
   modulePrefix: string;
   podModulePrefix: string;
-  locationType: 'history' | 'hash' | 'none';
+  locationType: "history" | "hash" | "none";
   rootURL: string;
   APP: Record<string, unknown>;
 };
 
-export default config;
\ No newline at end of file
+export default config;
diff --git a/frontend/app/models/absence-balance.js b/frontend/app/models/absence-balance.js
deleted file mode 100644
index ad425b658..000000000
--- a/frontend/app/models/absence-balance.js
+++ /dev/null
@@ -1,12 +0,0 @@
-import Model, { attr, belongsTo, hasMany } from "@ember-data/model";
-
-export default class AbsenceBalance extends Model {
-  @attr("number") credit;
-  @attr("number") usedDays;
-  @attr("django-duration") usedDuration;
-  @attr("number") balance;
-  @belongsTo("user", { async: false, inverse: "absenceBalances" }) user;
-  @belongsTo("absence-type", { async: false, inverse: "absenceBalances" })
-  absenceType;
-  @hasMany("absence-credit", { async: true, inverse: null }) absenceCredits;
-}
diff --git a/frontend/app/models/absence-balance.ts b/frontend/app/models/absence-balance.ts
new file mode 100644
index 000000000..6528f3d26
--- /dev/null
+++ b/frontend/app/models/absence-balance.ts
@@ -0,0 +1,29 @@
+import type { AsyncHasMany } from "@ember-data/model";
+import Model, { attr, belongsTo, hasMany } from "@ember-data/model";
+import type { Duration } from "moment";
+import type AbsenceCredit from "timed/models/absence-credit";
+import type AbsenceType from "timed/models/absence-type";
+import type User from "timed/models/user";
+
+export default class AbsenceBalance extends Model {
+  @attr("number")
+  declare credit?: number;
+  @attr("number")
+  declare usedDays?: number;
+  @attr("django-duration")
+  declare usedDuration?: Duration;
+  @attr("number")
+  declare balance?: number;
+  @belongsTo("user", { async: false, inverse: "absenceBalances" })
+  declare user: User;
+  @belongsTo("absence-type", { async: false, inverse: "absenceBalances" })
+  declare absenceType: AbsenceType;
+  @hasMany("absence-credit", { async: true, inverse: null })
+  declare absenceCredits: AsyncHasMany<AbsenceCredit>;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "absence-balance": AbsenceBalance;
+  }
+}
diff --git a/frontend/app/models/absence-credit.js b/frontend/app/models/absence-credit.ts
similarity index 54%
rename from frontend/app/models/absence-credit.js
rename to frontend/app/models/absence-credit.ts
index 417c3960c..2dc9969d1 100644
--- a/frontend/app/models/absence-credit.js
+++ b/frontend/app/models/absence-credit.ts
@@ -1,9 +1,12 @@
+import Model, { attr, belongsTo } from "@ember-data/model";
+import type { Moment } from "moment";
+import type AbsenceType from "timed/models/absence-type";
+import type User from "timed/models/user";
 /**
  * @module timed
  * @submodule timed-models
  * @public
  */
-import Model, { attr, belongsTo } from "@ember-data/model";
 
 /**
  * The absence credit model
@@ -19,7 +22,8 @@ export default class AbsenceCredit extends Model {
    * @property {Number} days
    * @public
    */
-  @attr("number") days;
+  @attr("number")
+  declare days?: number;
 
   /**
    * The date
@@ -27,7 +31,8 @@ export default class AbsenceCredit extends Model {
    * @property {moment} date
    * @public
    */
-  @attr("django-date") date;
+  @attr("django-date")
+  declare date?: Moment;
 
   /**
    * The comment
@@ -35,7 +40,8 @@ export default class AbsenceCredit extends Model {
    * @property {String} comment
    * @public
    */
-  @attr("string", { defaultValue: "" }) comment;
+  @attr("string", { defaultValue: "" })
+  declare comment: string;
 
   /**
    * The absence type for which this credit counts
@@ -43,7 +49,8 @@ export default class AbsenceCredit extends Model {
    * @property {AbsenceType} absenceType
    * @public
    */
-  @belongsTo("absence-type", { async: false, inverse: null }) absenceType;
+  @belongsTo("absence-type", { async: false, inverse: null })
+  declare absenceType: AbsenceType;
 
   /**
    * The user to which this credit belongs to
@@ -51,5 +58,12 @@ export default class AbsenceCredit extends Model {
    * @property {User} user
    * @public
    */
-  @belongsTo("user", { async: false, inverse: null }) user;
+  @belongsTo("user", { async: false, inverse: null })
+  declare user: User;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "absence-credit": AbsenceCredit;
+  }
 }
diff --git a/frontend/app/models/absence-type.js b/frontend/app/models/absence-type.ts
similarity index 63%
rename from frontend/app/models/absence-type.js
rename to frontend/app/models/absence-type.ts
index 21b97249e..313aa9c63 100644
--- a/frontend/app/models/absence-type.js
+++ b/frontend/app/models/absence-type.ts
@@ -1,9 +1,11 @@
+import type { AsyncHasMany } from "@ember-data/model";
 /**
  * @module timed
  * @submodule timed-models
  * @public
  */
 import Model, { attr, hasMany } from "@ember-data/model";
+import type AbsenceBalance from "timed/models/absence-balance";
 
 /**
  * The absence type model
@@ -21,7 +23,8 @@ export default class AbsenceType extends Model {
    * @property {String} name
    * @public
    */
-  @attr("string") name;
+  @attr("string")
+  declare name?: string;
 
   /**
    * Whether the absence type only fills the worktime
@@ -29,7 +32,8 @@ export default class AbsenceType extends Model {
    * @property {Boolean} fillWorktime
    * @public
    */
-  @attr("boolean") fillWorktime;
+  @attr("boolean")
+  declare fillWorktime?: boolean;
 
   /**
    * The balances for this type
@@ -38,5 +42,11 @@ export default class AbsenceType extends Model {
    * @public
    */
   @hasMany("absence-balance", { async: true, inverse: "absenceType" })
-  absenceBalances;
+  declare absenceBalances: AsyncHasMany<AbsenceBalance>;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "absence-type": AbsenceType;
+  }
 }
diff --git a/frontend/app/models/absence.js b/frontend/app/models/absence.ts
similarity index 53%
rename from frontend/app/models/absence.js
rename to frontend/app/models/absence.ts
index 630f1b91c..e315788d7 100644
--- a/frontend/app/models/absence.js
+++ b/frontend/app/models/absence.ts
@@ -1,10 +1,14 @@
+import type { AsyncBelongsTo } from "@ember-data/model";
+import Model, { attr, belongsTo } from "@ember-data/model";
+import type { Moment, Duration } from "moment";
 /**
  * @module timed
  * @submodule timed-models
  * @public
  */
-import Model, { attr, belongsTo } from "@ember-data/model";
 import moment from "moment";
+import type AbsenceType from "timed/models/absence-type";
+import type User from "timed/models/user";
 
 /**
  * The report model
@@ -20,7 +24,8 @@ export default class Absence extends Model {
    * @property {String} comment
    * @public
    */
-  @attr("string", { defaultValue: "" }) comment;
+  @attr("string", { defaultValue: "" })
+  declare comment: string;
 
   /**
    * The duration
@@ -28,7 +33,8 @@ export default class Absence extends Model {
    * @property {moment.duration} duration
    * @public
    */
-  @attr("django-duration", { defaultValue: () => moment.duration() }) duration;
+  @attr("django-duration", { defaultValue: () => moment.duration() })
+  declare duration: Duration;
 
   /**
    * The date
@@ -36,7 +42,8 @@ export default class Absence extends Model {
    * @property {moment} date
    * @public
    */
-  @attr("django-date") date;
+  @attr("django-date")
+  declare date?: Moment;
 
   /**
    * The type of the absence
@@ -44,7 +51,8 @@ export default class Absence extends Model {
    * @property {AbsenceType} absenceType
    * @public
    */
-  @belongsTo("absence-type", { async: false, inverse: null }) absenceType;
+  @belongsTo("absence-type", { async: false, inverse: null })
+  declare absenceType: AbsenceType;
 
   /**
    * The user
@@ -52,5 +60,12 @@ export default class Absence extends Model {
    * @property {User} user
    * @public
    */
-  @belongsTo("user", { async: true, inverse: null }) user;
+  @belongsTo("user", { async: true, inverse: null })
+  declare user: AsyncBelongsTo<User>;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    absence: Absence;
+  }
 }
diff --git a/frontend/app/models/activity.js b/frontend/app/models/activity.ts
similarity index 71%
rename from frontend/app/models/activity.js
rename to frontend/app/models/activity.ts
index e92782c43..82d58f175 100644
--- a/frontend/app/models/activity.js
+++ b/frontend/app/models/activity.ts
@@ -1,21 +1,36 @@
 import { service } from "@ember/service";
+import type { AsyncBelongsTo } from "@ember-data/model";
 import Model, { attr, belongsTo } from "@ember-data/model";
+import type StoreService from "@ember-data/store";
+import type NotifyService from "ember-notify";
+import type { Moment } from "moment";
 import moment from "moment";
 import { all } from "rsvp";
+import type Task from "timed/models/task";
+import type User from "timed/models/user";
 
 export default class Activity extends Model {
-  @attr("django-time") fromTime;
-  @attr("django-time") toTime;
-  @attr("string", { defaultValue: "" }) comment;
-  @attr("django-date") date;
-  @attr("boolean", { defaultValue: false }) transferred;
-  @attr("boolean", { defaultValue: false }) review;
-  @attr("boolean", { defaultValue: false }) notBillable;
-  @belongsTo("task", { async: true, inverse: null }) task;
-  @belongsTo("user", { async: true, inverse: null }) user;
-
-  @service notify;
-  @service store;
+  @attr("django-time")
+  declare fromTime?: Moment;
+  @attr("django-time")
+  declare toTime?: Moment;
+  @attr("string", { defaultValue: "" })
+  declare comment: string;
+  @attr("django-date")
+  declare date?: Moment;
+  @attr("boolean", { defaultValue: false })
+  declare transferred: boolean;
+  @attr("boolean", { defaultValue: false })
+  declare review: boolean;
+  @attr("boolean", { defaultValue: false })
+  declare notBillable: boolean;
+  @belongsTo("task", { async: true, inverse: null })
+  declare task: AsyncBelongsTo<Task>;
+  @belongsTo("user", { async: true, inverse: null })
+  declare user: AsyncBelongsTo<User>;
+
+  @service declare notify: NotifyService;
+  @service declare store: StoreService;
 
   get active() {
     return !this.toTime && !!this.id;
@@ -137,3 +152,9 @@ export default class Activity extends Model {
     }
   }
 }
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    activity: Activity;
+  }
+}
diff --git a/frontend/app/models/attendance.js b/frontend/app/models/attendance.ts
similarity index 67%
rename from frontend/app/models/attendance.js
rename to frontend/app/models/attendance.ts
index 34a6e8acc..848fc3280 100644
--- a/frontend/app/models/attendance.js
+++ b/frontend/app/models/attendance.ts
@@ -1,10 +1,13 @@
+import type { AsyncBelongsTo } from "@ember-data/model";
 /**
  * @module timed
  * @submodule timed-models
  * @public
  */
 import Model, { attr, belongsTo } from "@ember-data/model";
+import type { Moment } from "moment";
 import moment from "moment";
+import type User from "timed/models/user";
 
 /**
  * The attendance model
@@ -20,7 +23,8 @@ export default class Attendance extends Model {
    * @property {moment} date
    * @public
    */
-  @attr("django-date") date;
+  @attr("django-date")
+  declare date?: Moment;
 
   /**
    * The start time
@@ -28,7 +32,8 @@ export default class Attendance extends Model {
    * @property {moment} from
    * @public
    */
-  @attr("django-time") from;
+  @attr("django-time")
+  declare from?: Moment;
 
   /**
    * The end time
@@ -36,7 +41,8 @@ export default class Attendance extends Model {
    * @property {moment} to
    * @public
    */
-  @attr("django-time") to;
+  @attr("django-time")
+  declare to?: Moment;
 
   /**
    * The user
@@ -45,7 +51,8 @@ export default class Attendance extends Model {
    * @type {User}
    * @public
    */
-  @belongsTo("user", { async: true, inverse: null }) user;
+  @belongsTo("user", { async: true, inverse: null })
+  declare user: AsyncBelongsTo<User>;
 
   /**
    * The duration between start and end time
@@ -65,3 +72,9 @@ export default class Attendance extends Model {
     return moment.duration(calcTo.diff(this.from));
   }
 }
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    attendance: Attendance;
+  }
+}
diff --git a/frontend/app/models/billing-type.js b/frontend/app/models/billing-type.ts
similarity index 64%
rename from frontend/app/models/billing-type.js
rename to frontend/app/models/billing-type.ts
index de59d7548..b98463638 100644
--- a/frontend/app/models/billing-type.js
+++ b/frontend/app/models/billing-type.ts
@@ -19,5 +19,12 @@ export default class BillingType extends Model {
    * @property {String} name
    * @public
    */
-  @attr("string") name;
+  @attr("string")
+  declare name?: string;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "billing-type": BillingType;
+  }
 }
diff --git a/frontend/app/models/cost-center.js b/frontend/app/models/cost-center.js
deleted file mode 100644
index a1b80fb56..000000000
--- a/frontend/app/models/cost-center.js
+++ /dev/null
@@ -1,6 +0,0 @@
-import Model, { attr } from "@ember-data/model";
-
-export default class CostCenter extends Model {
-  @attr("string") name;
-  @attr("string") reference;
-}
diff --git a/frontend/app/models/cost-center.ts b/frontend/app/models/cost-center.ts
new file mode 100644
index 000000000..55a69c05a
--- /dev/null
+++ b/frontend/app/models/cost-center.ts
@@ -0,0 +1,14 @@
+import Model, { attr } from "@ember-data/model";
+
+export default class CostCenter extends Model {
+  @attr("string")
+  declare name?: string;
+  @attr("string")
+  declare reference?: string;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "cost-center": CostCenter;
+  }
+}
diff --git a/frontend/app/models/customer-assignee.js b/frontend/app/models/customer-assignee.ts
similarity index 53%
rename from frontend/app/models/customer-assignee.js
rename to frontend/app/models/customer-assignee.ts
index 678ea0ef4..aa10c5924 100644
--- a/frontend/app/models/customer-assignee.js
+++ b/frontend/app/models/customer-assignee.ts
@@ -1,9 +1,12 @@
+import type { AsyncBelongsTo } from "@ember-data/model";
 /**
  * @module timed
  * @submodule timed-models
  * @public
  */
 import Model, { attr, belongsTo } from "@ember-data/model";
+import type Customer from "timed/models/customer";
+import type User from "timed/models/user";
 
 /**
  * The customer assignee model
@@ -20,7 +23,8 @@ export default class CustomerAssignee extends Model {
    * @type {Customer}
    * @public
    */
-  @belongsTo("customer", { async: true, inverse: null }) customer;
+  @belongsTo("customer", { async: true, inverse: null })
+  declare customer: AsyncBelongsTo<Customer>;
   /**
    * The user
    *
@@ -28,7 +32,8 @@ export default class CustomerAssignee extends Model {
    * @type {User}
    * @public
    */
-  @belongsTo("user", { async: true, inverse: null }) user;
+  @belongsTo("user", { async: true, inverse: null })
+  declare user: AsyncBelongsTo<User>;
 
   /**
    * Whether the assignee is a reviewer
@@ -37,7 +42,8 @@ export default class CustomerAssignee extends Model {
    * @type {Boolean}
    * @public
    */
-  @attr("boolean", { defaultValue: false }) isReviewer;
+  @attr("boolean", { defaultValue: false })
+  declare isReviewer: boolean;
 
   /**
    * Whether the assignee is a manager
@@ -46,7 +52,8 @@ export default class CustomerAssignee extends Model {
    * @type {Boolean}
    * @public
    */
-  @attr("boolean", { defaultValue: false }) isManager;
+  @attr("boolean", { defaultValue: false })
+  declare isManager: boolean;
 
   /**
    * Whether the assignee is a resource
@@ -55,5 +62,12 @@ export default class CustomerAssignee extends Model {
    * @type {Boolean}
    * @public
    */
-  @attr("boolean", { defaultValue: false }) isResource;
+  @attr("boolean", { defaultValue: false })
+  declare isResource: boolean;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "customer-assignee": CustomerAssignee;
+  }
 }
diff --git a/frontend/app/models/customer-statistic.js b/frontend/app/models/customer-statistic.js
deleted file mode 100644
index 315e0a950..000000000
--- a/frontend/app/models/customer-statistic.js
+++ /dev/null
@@ -1,6 +0,0 @@
-import Model, { attr } from "@ember-data/model";
-
-export default class CustomerStatistics extends Model {
-  @attr("django-duration") duration;
-  @attr name;
-}
diff --git a/frontend/app/models/customer-statistic.ts b/frontend/app/models/customer-statistic.ts
new file mode 100644
index 000000000..9228708b8
--- /dev/null
+++ b/frontend/app/models/customer-statistic.ts
@@ -0,0 +1,15 @@
+import Model, { attr } from "@ember-data/model";
+import type { Duration } from "moment";
+
+export default class CustomerStatistics extends Model {
+  @attr("django-duration")
+  declare duration?: Duration;
+  @attr
+  declare name?: string;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "customer-statistic": CustomerStatistics;
+  }
+}
diff --git a/frontend/app/models/customer.js b/frontend/app/models/customer.ts
similarity index 56%
rename from frontend/app/models/customer.js
rename to frontend/app/models/customer.ts
index 49444cf6f..1494dc9a4 100644
--- a/frontend/app/models/customer.js
+++ b/frontend/app/models/customer.ts
@@ -1,9 +1,12 @@
+import type { AsyncHasMany } from "@ember-data/model";
+import Model, { attr, hasMany } from "@ember-data/model";
+import type CustomerAssignee from "timed/models/customer-assignee";
+import type Project from "timed/models/project";
 /**
  * @module timed
  * @submodule timed-models
  * @public
  */
-import Model, { attr, hasMany } from "@ember-data/model";
 
 /**
  * The customer model
@@ -20,7 +23,8 @@ export default class Customer extends Model {
    * @type {String}
    * @public
    */
-  @attr("string", { defaultValue: "" }) name;
+  @attr("string", { defaultValue: "" })
+  declare name: string;
 
   /**
    * Whether the project is archived
@@ -29,7 +33,8 @@ export default class Customer extends Model {
    * @type {Boolean}
    * @public
    */
-  @attr("boolean", { defaultValue: false }) archived;
+  @attr("boolean", { defaultValue: false })
+  declare archived: boolean;
 
   /**
    * The projects
@@ -38,7 +43,8 @@ export default class Customer extends Model {
    * @type {Project[]}
    * @public
    */
-  @hasMany("project", { async: true, inverse: "customer" }) projects;
+  @hasMany("project", { async: true, inverse: "customer" })
+  declare projects: AsyncHasMany<Project>;
 
   /**
    * Long name - alias for name, used for filtering in the customer box
@@ -57,5 +63,12 @@ export default class Customer extends Model {
    * @type {CustomerAssignee[]}
    * @public
    */
-  @hasMany("customer-assignee", { async: true, inverse: null }) assignees;
+  @hasMany("customer-assignee", { async: true, inverse: null })
+  declare assignees: AsyncHasMany<CustomerAssignee>;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    customer: Customer;
+  }
 }
diff --git a/frontend/app/models/employment.js b/frontend/app/models/employment.ts
similarity index 52%
rename from frontend/app/models/employment.js
rename to frontend/app/models/employment.ts
index 560ce4013..e1894bf97 100644
--- a/frontend/app/models/employment.js
+++ b/frontend/app/models/employment.ts
@@ -1,9 +1,13 @@
+import type { AsyncBelongsTo } from "@ember-data/model";
+import Model, { attr, belongsTo } from "@ember-data/model";
+import type { Moment, Duration } from "moment";
+import type Location from "timed/models/location";
 /**
  * @module timed
  * @submodule timed-models
  * @public
  */
-import Model, { attr, belongsTo } from "@ember-data/model";
+import type User from "timed/models/user";
 
 /**
  * The employment model
@@ -19,7 +23,8 @@ export default class Employment extends Model {
    * @property {Number} percentage
    * @public
    */
-  @attr("number") percentage;
+  @attr("number")
+  declare percentage?: number;
 
   /**
    * The time the user has to work every day
@@ -27,7 +32,8 @@ export default class Employment extends Model {
    * @property {moment.duration} worktimePerDay
    * @public
    */
-  @attr("django-duration") worktimePerDay;
+  @attr("django-duration")
+  declare worktimePerDay?: Duration;
 
   /**
    * The start date
@@ -35,7 +41,8 @@ export default class Employment extends Model {
    * @property {moment} start
    * @public
    */
-  @attr("django-date") start;
+  @attr("django-date")
+  declare start?: Moment;
 
   /**
    * Whether the employment is of an external employee
@@ -43,7 +50,8 @@ export default class Employment extends Model {
    * @property {Boolean} isExternal
    * @public
    */
-  @attr("boolean", { defaultValue: false }) isExternal;
+  @attr("boolean", { defaultValue: false })
+  declare isExternal: boolean;
 
   /**
    * The end date
@@ -51,7 +59,8 @@ export default class Employment extends Model {
    * @property {moment} end
    * @public
    */
-  @attr("django-date") end;
+  @attr("django-date")
+  declare end?: Moment;
 
   /**
    * The employed user
@@ -59,7 +68,8 @@ export default class Employment extends Model {
    * @property {User} user
    * @public
    */
-  @belongsTo("user", { async: true, inverse: "employments" }) user;
+  @belongsTo("user", { async: true, inverse: "employments" })
+  declare user: AsyncBelongsTo<User>;
 
   /**
    * The work location
@@ -67,5 +77,12 @@ export default class Employment extends Model {
    * @property {Location} location
    * @public
    */
-  @belongsTo("location", { async: true, inverse: null }) location;
+  @belongsTo("location", { async: true, inverse: null })
+  declare location: AsyncBelongsTo<Location>;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    employment: Employment;
+  }
 }
diff --git a/frontend/app/models/location.js b/frontend/app/models/location.ts
similarity index 66%
rename from frontend/app/models/location.js
rename to frontend/app/models/location.ts
index fe7c35580..8ce571d0e 100644
--- a/frontend/app/models/location.js
+++ b/frontend/app/models/location.ts
@@ -19,7 +19,8 @@ export default class Location extends Model {
    * @property {String} name
    * @public
    */
-  @attr("string") name;
+  @attr("string")
+  declare name?: string;
 
   /**
    * The days on which users in this location need to work
@@ -27,5 +28,12 @@ export default class Location extends Model {
    * @property {Number[]} workdays
    * @public
    */
-  @attr("django-workdays") workdays;
+  @attr("django-workdays")
+  declare workdays?: number[];
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    location: Location;
+  }
 }
diff --git a/frontend/app/models/month-statistic.js b/frontend/app/models/month-statistic.js
deleted file mode 100644
index bd36d4ea6..000000000
--- a/frontend/app/models/month-statistic.js
+++ /dev/null
@@ -1,7 +0,0 @@
-import Model, { attr } from "@ember-data/model";
-
-export default class MonthStatistic extends Model {
-  @attr("number") year;
-  @attr("number") month;
-  @attr("django-duration") duration;
-}
diff --git a/frontend/app/models/month-statistic.ts b/frontend/app/models/month-statistic.ts
new file mode 100644
index 000000000..785afce8f
--- /dev/null
+++ b/frontend/app/models/month-statistic.ts
@@ -0,0 +1,17 @@
+import Model, { attr } from "@ember-data/model";
+import type { Duration } from "moment";
+
+export default class MonthStatistic extends Model {
+  @attr("number")
+  declare year?: number;
+  @attr("number")
+  declare month?: number;
+  @attr("django-duration")
+  declare duration?: Duration;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "month-statistic": MonthStatistic;
+  }
+}
diff --git a/frontend/app/models/overtime-credit.js b/frontend/app/models/overtime-credit.js
deleted file mode 100644
index ba06c6308..000000000
--- a/frontend/app/models/overtime-credit.js
+++ /dev/null
@@ -1,8 +0,0 @@
-import Model, { attr, belongsTo } from "@ember-data/model";
-
-export default class OvertimeCredit extends Model {
-  @attr("django-date") date;
-  @attr("django-duration") duration;
-  @attr("string", { defaultValue: "" }) comment;
-  @belongsTo("user", { async: false, inverse: null }) user;
-}
diff --git a/frontend/app/models/overtime-credit.ts b/frontend/app/models/overtime-credit.ts
new file mode 100644
index 000000000..c5ecc905e
--- /dev/null
+++ b/frontend/app/models/overtime-credit.ts
@@ -0,0 +1,20 @@
+import Model, { attr, belongsTo } from "@ember-data/model";
+import type { Moment, Duration } from "moment";
+import type User from "timed/models/user";
+
+export default class OvertimeCredit extends Model {
+  @attr("django-date")
+  declare date?: Moment;
+  @attr("django-duration")
+  declare duration?: Duration;
+  @attr("string", { defaultValue: "" })
+  declare comment: string;
+  @belongsTo("user", { async: false, inverse: null })
+  declare user: User;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "overtime-credit": OvertimeCredit;
+  }
+}
diff --git a/frontend/app/models/project-assignee.js b/frontend/app/models/project-assignee.ts
similarity index 53%
rename from frontend/app/models/project-assignee.js
rename to frontend/app/models/project-assignee.ts
index 58a3b844e..efca09400 100644
--- a/frontend/app/models/project-assignee.js
+++ b/frontend/app/models/project-assignee.ts
@@ -1,9 +1,12 @@
+import type { AsyncBelongsTo } from "@ember-data/model";
 /**
  * @module timed
  * @submodule timed-models
  * @public
  */
 import Model, { attr, belongsTo } from "@ember-data/model";
+import type Project from "timed/models/project";
+import type User from "timed/models/user";
 
 /**
  * The project assignee model
@@ -20,7 +23,8 @@ export default class ProjectAssignee extends Model {
    * @type {Project}
    * @public
    */
-  @belongsTo("project", { async: true, inverse: null }) project;
+  @belongsTo("project", { async: true, inverse: null })
+  declare project: AsyncBelongsTo<Project>;
 
   /**
    * The user
@@ -29,7 +33,8 @@ export default class ProjectAssignee extends Model {
    * @type {User}
    * @public
    */
-  @belongsTo("user", { async: true, inverse: null }) user;
+  @belongsTo("user", { async: true, inverse: null })
+  declare user: AsyncBelongsTo<User>;
 
   /**
    * Whether the assignee is a reviewer
@@ -38,7 +43,8 @@ export default class ProjectAssignee extends Model {
    * @type {Boolean}
    * @public
    */
-  @attr("boolean", { defaultValue: false }) isReviewer;
+  @attr("boolean", { defaultValue: false })
+  declare isReviewer: boolean;
 
   /**
    * Whether the assignee is a manager
@@ -47,7 +53,8 @@ export default class ProjectAssignee extends Model {
    * @type {Boolean}
    * @public
    */
-  @attr("boolean", { defaultValue: false }) isManager;
+  @attr("boolean", { defaultValue: false })
+  declare isManager: boolean;
 
   /**
    * Whether the assignee is a resource
@@ -56,5 +63,12 @@ export default class ProjectAssignee extends Model {
    * @type {Boolean}
    * @public
    */
-  @attr("boolean", { defaultValue: false }) isResource;
+  @attr("boolean", { defaultValue: false })
+  declare isResource: boolean;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "project-assignee": ProjectAssignee;
+  }
 }
diff --git a/frontend/app/models/project-statistic.js b/frontend/app/models/project-statistic.js
deleted file mode 100644
index 12a607a84..000000000
--- a/frontend/app/models/project-statistic.js
+++ /dev/null
@@ -1,9 +0,0 @@
-import Model, { attr, belongsTo } from "@ember-data/model";
-
-export default class ProjectStatistics extends Model {
-  @attr name;
-  @attr("django-duration") estimatedTime;
-  @attr("django-duration") duration;
-  @attr("django-duration") totalRemainingEffort;
-  @belongsTo("customer", { async: true, inverse: null }) customer;
-}
diff --git a/frontend/app/models/project-statistic.ts b/frontend/app/models/project-statistic.ts
new file mode 100644
index 000000000..0b9c5c10e
--- /dev/null
+++ b/frontend/app/models/project-statistic.ts
@@ -0,0 +1,23 @@
+import type { AsyncBelongsTo } from "@ember-data/model";
+import Model, { attr, belongsTo } from "@ember-data/model";
+import type { Duration } from "moment";
+import type Customer from "timed/models/customer";
+
+export default class ProjectStatistics extends Model {
+  @attr
+  declare name?: string;
+  @attr("django-duration")
+  declare estimatedTime?: Duration;
+  @attr("django-duration")
+  declare duration?: Duration;
+  @attr("django-duration")
+  declare totalRemainingEffort?: Duration;
+  @belongsTo("customer", { async: true, inverse: null })
+  declare customer: AsyncBelongsTo<Customer>;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "project-statistic": ProjectStatistics;
+  }
+}
diff --git a/frontend/app/models/project.js b/frontend/app/models/project.ts
similarity index 51%
rename from frontend/app/models/project.js
rename to frontend/app/models/project.ts
index a5a0bb80f..1a9c52335 100644
--- a/frontend/app/models/project.js
+++ b/frontend/app/models/project.ts
@@ -1,9 +1,15 @@
+import type { AsyncBelongsTo, AsyncHasMany } from "@ember-data/model";
+import Model, { attr, belongsTo, hasMany } from "@ember-data/model";
+import type { Duration } from "moment";
+import type BillingType from "timed/models/billing-type";
+import type Customer from "timed/models/customer";
+import type ProjectAssignee from "timed/models/project-assignee";
+import type Task from "timed/models/task";
 /**
  * @module timed
  * @submodule timed-models
  * @public
  */
-import Model, { attr, belongsTo, hasMany } from "@ember-data/model";
 
 /**
  * The project model
@@ -20,7 +26,8 @@ export default class Project extends Model {
    * @type {String}
    * @public
    */
-  @attr("string", { defaultValue: "" }) name;
+  @attr("string", { defaultValue: "" })
+  declare name: string;
 
   /**
    * Whether the project is archived
@@ -29,7 +36,8 @@ export default class Project extends Model {
    * @type {Boolean}
    * @public
    */
-  @attr("boolean", { defaultValue: false }) archived;
+  @attr("boolean", { defaultValue: false })
+  declare archived: boolean;
 
   /**
    * The estimated time for this project
@@ -37,7 +45,8 @@ export default class Project extends Model {
    * @property {moment.duration} estimatedTime
    * @public
    */
-  @attr("django-duration") estimatedTime;
+  @attr("django-duration")
+  declare estimatedTime?: Duration;
 
   /**
    * Boolean indicating if the remainig effort should be trackable
@@ -45,14 +54,16 @@ export default class Project extends Model {
    * @type {Boolean}
    * @public
    */
-  @attr("boolean", { defaultValue: false }) remainingEffortTracking;
+  @attr("boolean", { defaultValue: false })
+  declare remainingEffortTracking: boolean;
 
   /**
    * Total remainig effort for this project
    * @property {moment.duration} estimatedtime
    * @public
    */
-  @attr("django-duration") totalRemainingEffort;
+  @attr("django-duration")
+  declare totalRemainingEffort?: Duration;
 
   /**
    * The customer
@@ -61,7 +72,8 @@ export default class Project extends Model {
    * @type {Customer}
    * @public
    */
-  @belongsTo("customer", { async: true, inverse: "projects" }) customer;
+  @belongsTo("customer", { async: true, inverse: "projects" })
+  declare customer: AsyncBelongsTo<Customer>;
 
   /**
    * Whether the project's comments are visible to the customer
@@ -70,7 +82,8 @@ export default class Project extends Model {
    * @type {Boolean}
    * @public
    */
-  @attr("boolean", { defaultValue: false }) customerVisible;
+  @attr("boolean", { defaultValue: false })
+  declare customerVisible: boolean;
 
   /**
    * The billing
@@ -78,7 +91,8 @@ export default class Project extends Model {
    * @property {BillingType} billingType
    * @public
    */
-  @belongsTo("billing-type", { async: false, inverse: null }) billingType;
+  @belongsTo("billing-type", { async: false, inverse: null })
+  declare billingType: BillingType;
 
   /**
    * The tasks
@@ -87,7 +101,8 @@ export default class Project extends Model {
    * @type {Task[]}
    * @public
    */
-  @hasMany("task", { async: true, inverse: "project" }) tasks;
+  @hasMany("task", { async: true, inverse: "project" })
+  declare tasks: AsyncHasMany<Task>;
 
   /**
    * Assigned users to this project
@@ -96,5 +111,12 @@ export default class Project extends Model {
    * @type {ProjectAssignee[]}
    * @public
    */
-  @hasMany("project-assignee", { async: true, inverse: null }) assignees;
+  @hasMany("project-assignee", { async: true, inverse: null })
+  declare assignees: AsyncHasMany<ProjectAssignee>;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    project: Project;
+  }
 }
diff --git a/frontend/app/models/public-holiday.js b/frontend/app/models/public-holiday.ts
similarity index 51%
rename from frontend/app/models/public-holiday.js
rename to frontend/app/models/public-holiday.ts
index 2bca8babc..3d7c10902 100644
--- a/frontend/app/models/public-holiday.js
+++ b/frontend/app/models/public-holiday.ts
@@ -1,9 +1,12 @@
+import type { AsyncBelongsTo } from "@ember-data/model";
 /**
  * @module timed
  * @submodule timed-models
  * @public
  */
 import Model, { attr, belongsTo } from "@ember-data/model";
+import type { Moment } from "moment";
+import type Location from "timed/models/location";
 
 /**
  * The public holiday model
@@ -19,7 +22,8 @@ export default class PublicHoliday extends Model {
    * @property {String} name
    * @public
    */
-  @attr("string") name;
+  @attr("string")
+  declare name?: string;
 
   /**
    * The date
@@ -27,7 +31,8 @@ export default class PublicHoliday extends Model {
    * @property {moment} date
    * @public
    */
-  @attr("django-date") date;
+  @attr("django-date")
+  declare date?: Moment;
 
   /**
    * The location
@@ -35,5 +40,12 @@ export default class PublicHoliday extends Model {
    * @property {Location} location
    * @public
    */
-  @belongsTo("location", { async: true, inverse: null }) location;
+  @belongsTo("location", { async: true, inverse: null })
+  declare location: AsyncBelongsTo<Location>;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "public-holiday": PublicHoliday;
+  }
 }
diff --git a/frontend/app/models/report-intersection.js b/frontend/app/models/report-intersection.js
deleted file mode 100644
index 8b3f2eb5c..000000000
--- a/frontend/app/models/report-intersection.js
+++ /dev/null
@@ -1,15 +0,0 @@
-import Model, { attr, belongsTo } from "@ember-data/model";
-
-export default class ReportIntersection extends Model {
-  @attr("string") comment;
-  @attr("boolean", { allowNull: true, defaultValue: null }) notBillable;
-  @attr("boolean", { allowNull: true, defaultValue: false }) rejected;
-  @attr("boolean", { allowNull: true, defaultValue: null }) review;
-  @attr("boolean", { allowNull: true, defaultValue: null }) billed;
-  @attr("boolean", { allowNull: true, defaultValue: null }) verified;
-
-  @belongsTo("customer", { async: true, inverse: null }) customer;
-  @belongsTo("project", { async: true, inverse: null }) project;
-  @belongsTo("task", { async: true, inverse: null }) task;
-  @belongsTo("user", { async: true, inverse: null }) user;
-}
diff --git a/frontend/app/models/report-intersection.ts b/frontend/app/models/report-intersection.ts
new file mode 100644
index 000000000..cb91c7c9e
--- /dev/null
+++ b/frontend/app/models/report-intersection.ts
@@ -0,0 +1,36 @@
+import type { AsyncBelongsTo } from "@ember-data/model";
+import Model, { attr, belongsTo } from "@ember-data/model";
+import type Customer from "timed/models/customer";
+import type Project from "timed/models/project";
+import type Task from "timed/models/task";
+import type User from "timed/models/user";
+
+export default class ReportIntersection extends Model {
+  @attr("string")
+  declare comment?: string;
+  @attr("boolean", { allowNull: true, defaultValue: null })
+  declare notBillable: boolean | null;
+  @attr("boolean", { allowNull: true, defaultValue: false })
+  declare rejected: boolean | null;
+  @attr("boolean", { allowNull: true, defaultValue: null })
+  declare review: boolean | null;
+  @attr("boolean", { allowNull: true, defaultValue: null })
+  declare billed: boolean | null;
+  @attr("boolean", { allowNull: true, defaultValue: null })
+  declare verified: boolean | null;
+
+  @belongsTo("customer", { async: true, inverse: null })
+  declare customer: AsyncBelongsTo<Customer>;
+  @belongsTo("project", { async: true, inverse: null })
+  declare project: AsyncBelongsTo<Project>;
+  @belongsTo("task", { async: true, inverse: null })
+  declare task: AsyncBelongsTo<Task>;
+  @belongsTo("user", { async: true, inverse: null })
+  declare user: AsyncBelongsTo<User>;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "report-intersection": ReportIntersection;
+  }
+}
diff --git a/frontend/app/models/report.js b/frontend/app/models/report.ts
similarity index 58%
rename from frontend/app/models/report.js
rename to frontend/app/models/report.ts
index 1407ecbff..2d46b3057 100644
--- a/frontend/app/models/report.js
+++ b/frontend/app/models/report.ts
@@ -1,10 +1,14 @@
+import type { AsyncBelongsTo } from "@ember-data/model";
+import Model, { attr, belongsTo } from "@ember-data/model";
+import type { Moment, Duration } from "moment";
 /**
  * @module timed
  * @submodule timed-models
  * @public
  */
-import Model, { attr, belongsTo } from "@ember-data/model";
 import moment from "moment";
+import type Task from "timed/models/task";
+import type User from "timed/models/user";
 
 /**
  * The report model
@@ -20,7 +24,8 @@ export default class Report extends Model {
    * @property {String} comment
    * @public
    */
-  @attr("string", { defaultValue: "" }) comment;
+  @attr("string", { defaultValue: "" })
+  declare comment: string;
 
   /**
    * The date
@@ -28,7 +33,8 @@ export default class Report extends Model {
    * @property {moment} date
    * @public
    */
-  @attr("django-date") date;
+  @attr("django-date")
+  declare date?: Moment;
 
   /**
    * The duration
@@ -36,7 +42,8 @@ export default class Report extends Model {
    * @property {moment.duration} duration
    * @public
    */
-  @attr("django-duration", { defaultValue: () => moment.duration() }) duration;
+  @attr("django-duration", { defaultValue: () => moment.duration() })
+  declare duration: Duration;
 
   /**
    * The remaining effort for the underlying task
@@ -46,7 +53,7 @@ export default class Report extends Model {
    */
 
   @attr("django-duration", { defaultValue: () => moment.duration() })
-  remainingEffort;
+  declare remainingEffort: Duration;
 
   /**
    * Whether the report needs to be reviewed
@@ -54,7 +61,8 @@ export default class Report extends Model {
    * @property {Boolean} review
    * @public
    */
-  @attr("boolean", { defaultValue: false }) review;
+  @attr("boolean", { defaultValue: false })
+  declare review: boolean;
 
   /**
    * Whether the report got rejected by the reviewer
@@ -62,7 +70,8 @@ export default class Report extends Model {
    * @property {Boolean} reject
    * @public
    */
-  @attr("boolean", { defaultValue: false }) rejected;
+  @attr("boolean", { defaultValue: false })
+  declare rejected: boolean;
 
   /**
    * Whether the report is not billable
@@ -70,7 +79,8 @@ export default class Report extends Model {
    * @property {Boolean} notBillable
    * @public
    */
-  @attr("boolean", { defaultValue: false }) notBillable;
+  @attr("boolean", { defaultValue: false })
+  declare notBillable: boolean;
 
   /**
    * Whether the report has been marked as billed
@@ -78,7 +88,8 @@ export default class Report extends Model {
    * @property {Boolean} billed
    * @public
    */
-  @attr("boolean", { defaultValue: false }) billed;
+  @attr("boolean", { defaultValue: false })
+  declare billed: boolean;
 
   /**
    * The task
@@ -86,7 +97,8 @@ export default class Report extends Model {
    * @property {Task} task
    * @public
    */
-  @belongsTo("task", { async: false, inverse: null }) task;
+  @belongsTo("task", { async: false, inverse: null })
+  declare task: Task;
 
   /**
    * The user
@@ -94,7 +106,8 @@ export default class Report extends Model {
    * @property {User} user
    * @public
    */
-  @belongsTo("user", { async: false, inverse: null }) user;
+  @belongsTo("user", { async: false, inverse: null })
+  declare user: User;
 
   /**
    * The user which verified this report
@@ -102,5 +115,12 @@ export default class Report extends Model {
    * @property {User} verifiedBy
    * @public
    */
-  @belongsTo("user", { async: true, inverse: null }) verifiedBy;
+  @belongsTo("user", { async: true, inverse: null })
+  declare verifiedBy: AsyncBelongsTo<User>;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    report: Report;
+  }
 }
diff --git a/frontend/app/models/task-assignee.js b/frontend/app/models/task-assignee.ts
similarity index 53%
rename from frontend/app/models/task-assignee.js
rename to frontend/app/models/task-assignee.ts
index 4f8a58bbe..b0aa65f5c 100644
--- a/frontend/app/models/task-assignee.js
+++ b/frontend/app/models/task-assignee.ts
@@ -1,9 +1,12 @@
+import type { AsyncBelongsTo } from "@ember-data/model";
 /**
  * @module timed
  * @submodule timed-models
  * @public
  */
 import Model, { attr, belongsTo } from "@ember-data/model";
+import type Task from "timed/models/task";
+import type User from "timed/models/user";
 
 /**
  * The task assignee model
@@ -20,7 +23,8 @@ export default class TaskAssignee extends Model {
    * @type {Task}
    * @public
    */
-  @belongsTo("task", { async: true, inverse: "assignees" }) task;
+  @belongsTo("task", { async: true, inverse: "assignees" })
+  declare task: AsyncBelongsTo<Task>;
   /**
    * The user
    *
@@ -28,7 +32,8 @@ export default class TaskAssignee extends Model {
    * @type {User}
    * @public
    */
-  @belongsTo("user", { async: true, inverse: null }) user;
+  @belongsTo("user", { async: true, inverse: null })
+  declare user: AsyncBelongsTo<User>;
 
   /**
    * Whether the assignee is a reviewer
@@ -37,7 +42,8 @@ export default class TaskAssignee extends Model {
    * @type {Boolean}
    * @public
    */
-  @attr("boolean", { defaultValue: false }) isReviewer;
+  @attr("boolean", { defaultValue: false })
+  declare isReviewer: boolean;
 
   /**
    * Whether the assignee is a manager
@@ -46,7 +52,8 @@ export default class TaskAssignee extends Model {
    * @type {Boolean}
    * @public
    */
-  @attr("boolean", { defaultValue: false }) isManager;
+  @attr("boolean", { defaultValue: false })
+  declare isManager: boolean;
 
   /**
    * Whether the assignee is a resource
@@ -55,5 +62,12 @@ export default class TaskAssignee extends Model {
    * @type {Boolean}
    * @public
    */
-  @attr("boolean", { defaultValue: false }) isResource;
+  @attr("boolean", { defaultValue: false })
+  declare isResource: boolean;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "task-assignee": TaskAssignee;
+  }
 }
diff --git a/frontend/app/models/task-statistic.js b/frontend/app/models/task-statistic.js
deleted file mode 100644
index b9a234e25..000000000
--- a/frontend/app/models/task-statistic.js
+++ /dev/null
@@ -1,9 +0,0 @@
-import Model, { attr, belongsTo } from "@ember-data/model";
-
-export default class TaskStatistics extends Model {
-  @attr name;
-  @attr("django-duration") duration;
-  @attr("django-duration") estimatedTime;
-  @attr("django-duration") mostRecentRemainingEffort;
-  @belongsTo("project", { async: true, inverse: null }) project;
-}
diff --git a/frontend/app/models/task-statistic.ts b/frontend/app/models/task-statistic.ts
new file mode 100644
index 000000000..f29748873
--- /dev/null
+++ b/frontend/app/models/task-statistic.ts
@@ -0,0 +1,23 @@
+import type { AsyncBelongsTo } from "@ember-data/model";
+import Model, { attr, belongsTo } from "@ember-data/model";
+import type { Duration } from "moment";
+import type Project from "timed/models/project";
+
+export default class TaskStatistics extends Model {
+  @attr
+  declare name?: string;
+  @attr("django-duration")
+  declare duration?: Duration;
+  @attr("django-duration")
+  declare estimatedTime?: Duration;
+  @attr("django-duration")
+  declare mostRecentRemainingEffort?: Duration;
+  @belongsTo("project", { async: true, inverse: null })
+  declare project: AsyncBelongsTo<Project>;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "task-statistic": TaskStatistics;
+  }
+}
diff --git a/frontend/app/models/task.js b/frontend/app/models/task.js
deleted file mode 100644
index 9882f902b..000000000
--- a/frontend/app/models/task.js
+++ /dev/null
@@ -1,40 +0,0 @@
-import Model, { attr, belongsTo, hasMany } from "@ember-data/model";
-
-export default class Task extends Model {
-  @attr("string", { defaultValue: "" }) name;
-  @attr("django-duration") estimatedTime;
-  @attr("django-duration") mostRecentRemainingEffort;
-  @attr("boolean", { defaultValue: false }) archived;
-  @attr("string", { defaultValue: "" }) reference;
-
-  @belongsTo("project", {
-    async: true,
-    inverse: "tasks",
-  })
-  project;
-  @hasMany("task-assignee", {
-    async: true,
-    inverse: "task",
-  })
-  assignees;
-
-  /**
-   * Flag saying that this is a task.
-   * Used in /app/customer-suggestion/template.hbs
-   * We're using this as a workaround for the fact that one
-   * can't seem to use helpers like "(eq" in inline templates
-   *
-   * @property project
-   * @type {Project}
-   * @public
-   */
-  isTask = true;
-
-  get longName() {
-    const taskName = this.name;
-    const projectName = this.project.get("name");
-    const customerName = this.project.get("customer.name");
-
-    return `${customerName} > ${projectName} > ${taskName}`;
-  }
-}
diff --git a/frontend/app/models/task.ts b/frontend/app/models/task.ts
new file mode 100644
index 000000000..ef4174f54
--- /dev/null
+++ b/frontend/app/models/task.ts
@@ -0,0 +1,60 @@
+import Model, {
+  attr,
+  belongsTo,
+  hasMany,
+  type AsyncBelongsTo,
+  type AsyncHasMany,
+} from "@ember-data/model";
+import type { Duration } from "moment";
+import type Project from "timed/models/project";
+import type TaskAssignee from "timed/models/task-assignee";
+
+export default class Task extends Model {
+  @attr("string", { defaultValue: "" })
+  declare name: string;
+  @attr("django-duration")
+  declare estimatedTime?: Duration;
+  @attr("django-duration")
+  declare mostRecentRemainingEffort?: Duration;
+  @attr("boolean", { defaultValue: false })
+  declare archived: boolean;
+  @attr("string", { defaultValue: "" })
+  declare reference: string;
+
+  @belongsTo("project", {
+    async: true,
+    inverse: "tasks",
+  })
+  declare project: AsyncBelongsTo<Project>;
+  @hasMany("task-assignee", {
+    async: true,
+    inverse: "task",
+  })
+  declare assignees: AsyncHasMany<TaskAssignee>;
+
+  /**
+   * Flag saying that this is a task.
+   * Used in /app/customer-suggestion/template.hbs
+   * We're using this as a workaround for the fact that one
+   * can't seem to use helpers like "(eq" in inline templates
+   *
+   * @property project
+   * @type {Project}
+   * @public
+   */
+  isTask = true;
+
+  get longName() {
+    const taskName = this.name;
+    const projectName = this.project.get("name");
+    const customerName = this.project.get("customer.name");
+
+    return `${customerName} > ${projectName} > ${taskName}`;
+  }
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    task: Task;
+  }
+}
diff --git a/frontend/app/models/user-statistic.js b/frontend/app/models/user-statistic.js
deleted file mode 100644
index 1785551fe..000000000
--- a/frontend/app/models/user-statistic.js
+++ /dev/null
@@ -1,7 +0,0 @@
-import Model, { attr, belongsTo } from "@ember-data/model";
-
-export default class UserStatistic extends Model {
-  @attr("django-duration") duration;
-
-  @belongsTo("user", { async: true, inverse: null }) user;
-}
diff --git a/frontend/app/models/user-statistic.ts b/frontend/app/models/user-statistic.ts
new file mode 100644
index 000000000..4fff5d017
--- /dev/null
+++ b/frontend/app/models/user-statistic.ts
@@ -0,0 +1,18 @@
+import type { AsyncBelongsTo } from "@ember-data/model";
+import Model, { attr, belongsTo } from "@ember-data/model";
+import type { Duration } from "moment";
+import type User from "timed/models/user";
+
+export default class UserStatistic extends Model {
+  @attr("django-duration")
+  declare duration?: Duration;
+
+  @belongsTo("user", { async: true, inverse: null })
+  declare user: AsyncBelongsTo<User>;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "user-statistic": UserStatistic;
+  }
+}
diff --git a/frontend/app/models/user.js b/frontend/app/models/user.ts
similarity index 68%
rename from frontend/app/models/user.js
rename to frontend/app/models/user.ts
index 3db1a1a6c..19f3eb5c2 100644
--- a/frontend/app/models/user.js
+++ b/frontend/app/models/user.ts
@@ -1,11 +1,16 @@
+import { service } from "@ember/service";
+import type { SyncHasMany, AsyncHasMany } from "@ember-data/model";
 /**
  * @module timed
  * @submodule timed-models
  * @public
  */
-import { service } from "@ember/service";
 import Model, { attr, hasMany } from "@ember-data/model";
+import type StoreService from "@ember-data/store";
 import moment from "moment";
+import type AbsenceBalance from "timed/models/absence-balance";
+import type Employment from "timed/models/employment";
+import type WorktimeBalance from "timed/models/worktime-balance";
 /**
  * The user model
  *
@@ -14,14 +19,15 @@ import moment from "moment";
  * @public
  */
 export default class User extends Model {
-  @service store;
+  @service declare store: StoreService;
   /**
    * The username
    *
    * @property {String} username
    * @public
    */
-  @attr("string") username;
+  @attr("string")
+  declare username?: string;
 
   /**
    * The first name
@@ -29,7 +35,8 @@ export default class User extends Model {
    * @property {String} firstName
    * @public
    */
-  @attr("string") firstName;
+  @attr("string")
+  declare firstName?: string;
 
   /**
    * The last name
@@ -37,7 +44,8 @@ export default class User extends Model {
    * @property {String} lastName
    * @public
    */
-  @attr("string") lastName;
+  @attr("string")
+  declare lastName?: string;
 
   /**
    * The email address
@@ -45,7 +53,8 @@ export default class User extends Model {
    * @property {String} email
    * @public
    */
-  @attr("string") email;
+  @attr("string")
+  declare email?: string;
 
   /**
    * Defines if the user is a superuser
@@ -53,7 +62,8 @@ export default class User extends Model {
    * @property {Boolean} isSuperuser
    * @public
    */
-  @attr("boolean") isSuperuser;
+  @attr("boolean")
+  declare isSuperuser?: boolean;
 
   /**
    * Whether a user is active
@@ -61,7 +71,8 @@ export default class User extends Model {
    * @property {Boolean} isActive
    * @public
    */
-  @attr("boolean") isActive;
+  @attr("boolean")
+  declare isActive?: boolean;
 
   /**
    * Whether the user is a reviewer in a project
@@ -69,12 +80,14 @@ export default class User extends Model {
    * @property {Boolean} isReviewer
    * @public
    */
-  @attr("boolean") isReviewer;
+  @attr("boolean")
+  declare isReviewer?: boolean;
 
   /**
    * Whether the user is an accountant
    */
-  @attr("boolean", { defaultValue: false }) isAccountant;
+  @attr("boolean", { defaultValue: false })
+  declare isAccountant: boolean;
 
   /**
    * Whether the user completed the app tour
@@ -82,7 +95,8 @@ export default class User extends Model {
    * @property {Boolean} tourDone
    * @public
    */
-  @attr("boolean") tourDone;
+  @attr("boolean")
+  declare tourDone?: boolean;
 
   /**
    * The users supervisors
@@ -90,7 +104,8 @@ export default class User extends Model {
    * @property {User[]} supervisors
    * @public
    */
-  @hasMany("user", { inverse: "supervisees", async: false }) supervisors;
+  @hasMany("user", { inverse: "supervisees", async: false })
+  declare supervisors: SyncHasMany<User>;
 
   /**
    * The users supervisees
@@ -98,7 +113,8 @@ export default class User extends Model {
    * @property {User[]} supervisees
    * @public
    */
-  @hasMany("user", { inverse: "supervisors", async: false }) supervisees;
+  @hasMany("user", { inverse: "supervisors", async: false })
+  declare supervisees: SyncHasMany<User>;
 
   /**
    * The users employments
@@ -106,7 +122,8 @@ export default class User extends Model {
    * @property {Employment[]} employments
    * @public
    */
-  @hasMany("employment", { async: true, inverse: "user" }) employments;
+  @hasMany("employment", { async: true, inverse: "user" })
+  declare employments: AsyncHasMany<Employment>;
 
   /**
    * The users worktime balances
@@ -114,8 +131,8 @@ export default class User extends Model {
    * @property {WorktimeBalance[]} worktimeBalances
    * @public
    */
-  @hasMany("worktime-balances", { async: true, inverse: "user" })
-  worktimeBalances;
+  @hasMany("worktime-balance", { async: true, inverse: "user" })
+  declare worktimeBalances: AsyncHasMany<WorktimeBalance>;
 
   /**
    * The users absence balances
@@ -123,7 +140,8 @@ export default class User extends Model {
    * @property {AbsenceBalance[]} absenceBalances
    * @public
    */
-  @hasMany("absence-balance", { async: true, inverse: "user" }) absenceBalances;
+  @hasMany("absence-balance", { async: true, inverse: "user" })
+  declare absenceBalances: AsyncHasMany<AbsenceBalance>;
 
   /**
    * The full name
@@ -200,3 +218,9 @@ export default class User extends Model {
     };
   }
 }
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    user: User;
+  }
+}
diff --git a/frontend/app/models/worktime-balance.js b/frontend/app/models/worktime-balance.js
deleted file mode 100644
index f7cb73ead..000000000
--- a/frontend/app/models/worktime-balance.js
+++ /dev/null
@@ -1,7 +0,0 @@
-import Model, { attr, belongsTo } from "@ember-data/model";
-
-export default class WorktimeBalance extends Model {
-  @attr("django-date") date;
-  @attr("django-duration") balance;
-  @belongsTo("user", { async: true, inverse: "worktimeBalances" }) user;
-}
diff --git a/frontend/app/models/worktime-balance.ts b/frontend/app/models/worktime-balance.ts
new file mode 100644
index 000000000..6c78a1bf5
--- /dev/null
+++ b/frontend/app/models/worktime-balance.ts
@@ -0,0 +1,19 @@
+import type { AsyncBelongsTo } from "@ember-data/model";
+import Model, { attr, belongsTo } from "@ember-data/model";
+import type { Moment, Duration } from "moment";
+import type User from "timed/models/user";
+
+export default class WorktimeBalance extends Model {
+  @attr("django-date")
+  declare date?: Moment;
+  @attr("django-duration")
+  declare balance?: Duration;
+  @belongsTo("user", { async: true, inverse: "worktimeBalances" })
+  declare user: AsyncBelongsTo<User>;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "worktime-balance": WorktimeBalance;
+  }
+}
diff --git a/frontend/app/models/year-statistic.js b/frontend/app/models/year-statistic.js
deleted file mode 100644
index 54108d33d..000000000
--- a/frontend/app/models/year-statistic.js
+++ /dev/null
@@ -1,6 +0,0 @@
-import Model, { attr } from "@ember-data/model";
-
-export default class YearStatistic extends Model {
-  @attr("number") year;
-  @attr("django-duration") duration;
-}
diff --git a/frontend/app/models/year-statistic.ts b/frontend/app/models/year-statistic.ts
new file mode 100644
index 000000000..efc322677
--- /dev/null
+++ b/frontend/app/models/year-statistic.ts
@@ -0,0 +1,15 @@
+import Model, { attr } from "@ember-data/model";
+import type { Duration } from "moment";
+
+export default class YearStatistic extends Model {
+  @attr("number")
+  declare year?: number;
+  @attr("django-duration")
+  declare duration?: Duration;
+}
+
+declare module "ember-data/types/registries/model" {
+  export default interface ModelRegistry {
+    "year-statistic": YearStatistic;
+  }
+}
diff --git a/frontend/app/serializers/application.js b/frontend/app/serializers/application.ts
similarity index 100%
rename from frontend/app/serializers/application.js
rename to frontend/app/serializers/application.ts
diff --git a/frontend/app/serializers/attendance.js b/frontend/app/serializers/attendance.ts
similarity index 80%
rename from frontend/app/serializers/attendance.js
rename to frontend/app/serializers/attendance.ts
index 1ec78c342..2eb787613 100644
--- a/frontend/app/serializers/attendance.js
+++ b/frontend/app/serializers/attendance.ts
@@ -29,3 +29,9 @@ export default class AttendanceSerializer extends ApplicationSerializer {
     to: "to-time",
   };
 }
+
+declare module "ember-data/types/registries/serializer" {
+  export default interface SerializerRegistry {
+    attendance: AttendanceSerializer;
+  }
+}
diff --git a/frontend/app/serializers/employment.js b/frontend/app/serializers/employment.ts
similarity index 80%
rename from frontend/app/serializers/employment.js
rename to frontend/app/serializers/employment.ts
index 4b6761adc..17ad424e9 100644
--- a/frontend/app/serializers/employment.js
+++ b/frontend/app/serializers/employment.ts
@@ -29,3 +29,9 @@ export default class EmploymentSerializer extends ApplicationSerializer {
     end: "end-date",
   };
 }
+
+declare module "ember-data/types/registries/serializer" {
+  export default interface SerializerRegistry {
+    employment: EmploymentSerializer;
+  }
+}
diff --git a/frontend/app/services/autostart-tour.js b/frontend/app/services/autostart-tour.ts
similarity index 88%
rename from frontend/app/services/autostart-tour.js
rename to frontend/app/services/autostart-tour.ts
index 65e326a6b..cbb4d433e 100644
--- a/frontend/app/services/autostart-tour.js
+++ b/frontend/app/services/autostart-tour.ts
@@ -37,3 +37,9 @@ export default class AutostartTourService extends Service {
     return this.undoneTours.length === 0;
   }
 }
+
+declare module "@ember/service" {
+  interface Registry {
+    "autostart-tour": AutostartTourService;
+  }
+}
diff --git a/frontend/app/services/current-user.js b/frontend/app/services/current-user.ts
similarity index 62%
rename from frontend/app/services/current-user.js
rename to frontend/app/services/current-user.ts
index d2e6524e2..2e5dc37f6 100644
--- a/frontend/app/services/current-user.js
+++ b/frontend/app/services/current-user.ts
@@ -1,11 +1,15 @@
+import type RouterService from "@ember/routing/router-service";
 import Service, { service } from "@ember/service";
+import type StoreService from "@ember-data/store";
+import type SessionService from "ember-simple-auth-oidc/services/session";
 import moment from "moment";
+import type FetchService from "timed/services/fetch";
 
 export default class CurrentUserService extends Service {
-  @service session;
-  @service fetch;
-  @service store;
-  @service router;
+  @service declare session: SessionService;
+  @service declare fetch: FetchService;
+  @service declare store: StoreService;
+  @service declare router: RouterService;
 
   async load() {
     if (!this.session.isAuthenticated) {
@@ -38,3 +42,9 @@ export default class CurrentUserService extends Service {
     this.user = usermodel;
   }
 }
+
+declare module "@ember/service" {
+  interface Registry {
+    "current-user": CurrentUserService;
+  }
+}
diff --git a/frontend/app/services/fetch.js b/frontend/app/services/fetch.ts
similarity index 92%
rename from frontend/app/services/fetch.js
rename to frontend/app/services/fetch.ts
index e950f900f..46e2f3ccb 100644
--- a/frontend/app/services/fetch.js
+++ b/frontend/app/services/fetch.ts
@@ -2,6 +2,7 @@ import Service, { service } from "@ember/service";
 import { isEmpty } from "@ember/utils";
 import { isUnauthorizedResponse } from "ember-fetch/errors";
 import { handleUnauthorized } from "ember-simple-auth-oidc";
+import type SessionService from "ember-simple-auth-oidc/services/session";
 import fetch from "fetch";
 
 const CONTENT_TYPE = "application/vnd.api+json";
@@ -40,7 +41,7 @@ const stringifyBodyData = (obj) => {
 };
 
 export default class FetchService extends Service {
-  @service session;
+  @service declare session: SessionService;
 
   async fetch(resource, init = {}) {
     await this.session.refreshAuthentication.perform();
@@ -97,3 +98,9 @@ export default class FetchService extends Service {
     };
   }
 }
+
+declare module "@ember/service" {
+  interface Registry {
+    fetch: FetchService;
+  }
+}
diff --git a/frontend/app/services/metadata-fetcher.js b/frontend/app/services/metadata-fetcher.ts
similarity index 92%
rename from frontend/app/services/metadata-fetcher.js
rename to frontend/app/services/metadata-fetcher.ts
index eeb9f7429..7312781fa 100644
--- a/frontend/app/services/metadata-fetcher.js
+++ b/frontend/app/services/metadata-fetcher.ts
@@ -1,6 +1,7 @@
 import Service, { service } from "@ember/service";
 import { camelize, capitalize, dasherize } from "@ember/string";
 import { restartableTask } from "ember-concurrency";
+import type FetchService from "timed/services/fetch";
 import DjangoDurationTransform from "timed/transforms/django-duration";
 
 const DJANGO_DURATION_TRANSFORM = DjangoDurationTransform.create();
@@ -45,7 +46,7 @@ export default class MetadataFetcherService extends Service {
    * @property {Emberfetch} fetch
    * @public
    */
-  @service fetch;
+  @service declare fetch: FetchService;
 
   /**
    * Task to fetch a single records metadata
@@ -95,3 +96,9 @@ export default class MetadataFetcherService extends Service {
     return { ...attributesValues, ...metaValues };
   }
 }
+
+declare module "@ember/service" {
+  interface Registry {
+    "metadata-fetcher": MetadataFetcherService;
+  }
+}
diff --git a/frontend/app/services/rejected-reports.js b/frontend/app/services/rejected-reports.ts
similarity index 73%
rename from frontend/app/services/rejected-reports.js
rename to frontend/app/services/rejected-reports.ts
index 88197b3ae..06bbb9dc4 100644
--- a/frontend/app/services/rejected-reports.js
+++ b/frontend/app/services/rejected-reports.ts
@@ -1,15 +1,18 @@
 import Service, { service } from "@ember/service";
+import type StoreService from "@ember-data/store";
 import { macroCondition, isTesting } from "@embroider/macros";
 import { tracked } from "@glimmer/tracking";
+import type NotifyService from "ember-notify";
+import type CurrentUserService from "timed/services/current-user";
 
 const INTERVAL_DELAY = 10 * 60000; // 10 Minutes
 
 export default class RejectedReportsService extends Service {
-  @service store;
+  @service declare store: StoreService;
 
-  @service currentUser;
+  @service declare currentUser: CurrentUserService;
 
-  @service notify;
+  @service declare notify: NotifyService;
 
   @tracked amountReports = 0;
   @tracked intervalId;
@@ -53,3 +56,9 @@ export default class RejectedReportsService extends Service {
     clearInterval(this.intervalId);
   }
 }
+
+declare module "@ember/service" {
+  interface Registry {
+    "rejected-reports": RejectedReportsService;
+  }
+}
diff --git a/frontend/app/services/tour.js b/frontend/app/services/tour.ts
similarity index 87%
rename from frontend/app/services/tour.js
rename to frontend/app/services/tour.ts
index d57f0ac1f..2d4f32200 100644
--- a/frontend/app/services/tour.js
+++ b/frontend/app/services/tour.ts
@@ -1,17 +1,21 @@
+import type RouterService from "@ember/routing/router-service";
 import { schedule, later } from "@ember/runloop";
 import { service } from "@ember/service";
 import { waitFor } from "@ember/test-waiters";
 import { isTesting, macroCondition } from "@embroider/macros";
 import { tracked } from "@glimmer/tracking";
+import type NotifyService from "ember-notify";
 import Tour from "ember-shepherd/services/tour";
+import type AutostartTourService from "timed/services/autostart-tour";
+import type MediaService from "timed/services/media";
 import TOURS from "timed/tours";
 import { cached } from "tracked-toolbox";
 
 export default class TourService extends Tour {
-  @service notify;
-  @service media;
-  @service router;
-  @service autostartTour;
+  @service declare notify: NotifyService;
+  @service declare media: MediaService;
+  @service declare router: RouterService;
+  @service declare autostartTour: AutostartTourService;
   @tracked model;
 
   constructor(...args) {
@@ -51,8 +55,7 @@ export default class TourService extends Tour {
     super.willDestroy(...args);
   }
 
-  @cached
-  get routeName() {
+  @cached get routeName() {
     return this.router.currentRouteName.replace(/\.index$/, "");
   }
 
@@ -132,8 +135,7 @@ export default class TourService extends Tour {
     }
   }
 
-  @waitFor
-  async startTour() {
+  @waitFor async startTour() {
     if (this._wantsTour && this.hasTourForRoute) {
       await this.prepareTourForCurrentRoute();
       schedule("afterRender", this, () => {
@@ -172,3 +174,9 @@ export default class TourService extends Tour {
     }
   }
 }
+
+declare module "@ember/service" {
+  interface Registry {
+    tour: TourService;
+  }
+}
diff --git a/frontend/app/services/tracking.js b/frontend/app/services/tracking.ts
similarity index 96%
rename from frontend/app/services/tracking.js
rename to frontend/app/services/tracking.ts
index 0df09deef..9f9569e5f 100644
--- a/frontend/app/services/tracking.js
+++ b/frontend/app/services/tracking.ts
@@ -2,9 +2,11 @@ import { getOwner } from "@ember/application";
 import { scheduleOnce } from "@ember/runloop";
 import Service, { service } from "@ember/service";
 import { camelize, capitalize } from "@ember/string";
+import type StoreService from "@ember-data/store";
 import { isTesting, macroCondition } from "@embroider/macros";
 import { tracked } from "@glimmer/tracking";
 import { dropTask, task, timeout } from "ember-concurrency";
+import type NotifyService from "ember-notify";
 import { trackedTask } from "ember-resources/util/ember-concurrency";
 import moment from "moment";
 import formatDuration from "timed/utils/format-duration";
@@ -25,7 +27,7 @@ export default class TrackingService extends Service {
    * @property {Ember.Store} store
    * @public
    */
-  @service store;
+  @service declare store: StoreService;
 
   /**
    * The notify service
@@ -33,7 +35,7 @@ export default class TrackingService extends Service {
    * @property {EmberNotify.NotifyService} notify
    * @public
    */
-  @service notify;
+  @service declare notify: NotifyService;
 
   /**
    * Flag indicating if the tracking reports is currently generated.
@@ -363,3 +365,9 @@ export default class TrackingService extends Service {
     return;
   }
 }
+
+declare module "@ember/service" {
+  interface Registry {
+    tracking: TrackingService;
+  }
+}
diff --git a/frontend/app/services/unverified-reports.js b/frontend/app/services/unverified-reports.ts
similarity index 77%
rename from frontend/app/services/unverified-reports.js
rename to frontend/app/services/unverified-reports.ts
index b320b70e8..b6579c8d2 100644
--- a/frontend/app/services/unverified-reports.js
+++ b/frontend/app/services/unverified-reports.ts
@@ -1,7 +1,10 @@
 import Service, { service } from "@ember/service";
+import type StoreService from "@ember-data/store";
 import { isTesting, macroCondition } from "@embroider/macros";
 import { tracked } from "@glimmer/tracking";
+import type NotifyService from "ember-notify";
 import moment from "moment";
+import type CurrentUserService from "timed/services/current-user";
 
 const INTERVAL_DELAY = 10 * 60000; // 10 Minutes
 
@@ -16,11 +19,11 @@ const INTERVAL_DELAY = 10 * 60000; // 10 Minutes
  * @public
  */
 export default class UnverifiedReportsService extends Service {
-  @service store;
+  @service declare store: StoreService;
 
-  @service currentUser;
+  @service declare currentUser: CurrentUserService;
 
-  @service notify;
+  @service declare notify: NotifyService;
 
   @tracked amountReports = 0;
 
@@ -65,3 +68,9 @@ export default class UnverifiedReportsService extends Service {
     clearInterval(this.intervalId);
   }
 }
+
+declare module "@ember/service" {
+  interface Registry {
+    "unverified-reports": UnverifiedReportsService;
+  }
+}
diff --git a/frontend/app/transforms/django-date.ts b/frontend/app/transforms/django-date.ts
new file mode 100644
index 000000000..1a0f042bc
--- /dev/null
+++ b/frontend/app/transforms/django-date.ts
@@ -0,0 +1,26 @@
+import MomentTransform from "timed/transforms/moment";
+
+/**
+ * The django date transform
+ *
+ * This transforms a django date into a moment date
+ *
+ * @class DjangoDateTransform
+ * @extends MomentTransform
+ * @public
+ */
+export default class DjangoDateTransform extends MomentTransform {
+  /**
+   * The date format
+   *
+   * @property {String} format
+   * @public
+   */
+  format = "YYYY-MM-DD";
+}
+
+declare module "ember-data/types/registries/transform" {
+  export default interface TransformRegistry {
+    "django-date": DjangoDateTransform;
+  }
+}
diff --git a/frontend/app/transforms/django-datetime.ts b/frontend/app/transforms/django-datetime.ts
new file mode 100644
index 000000000..dc4137ee4
--- /dev/null
+++ b/frontend/app/transforms/django-datetime.ts
@@ -0,0 +1,26 @@
+import MomentTransform from "timed/transforms/moment";
+
+/**
+ * The django datetime transform
+ *
+ * This transforms a django datetime into a moment datetime
+ *
+ * @class DjangoDatetimeTransform
+ * @extends MomentTransform
+ * @public
+ */
+export default class DjangoDatetimeTransform extends MomentTransform {
+  /**
+   * The date format
+   *
+   * @property {String} format
+   * @public
+   */
+  format = "YYYY-MM-DDTHH:mm:ss.SSSSZ";
+}
+
+declare module "ember-data/types/registries/transform" {
+  export default interface TransformRegistry {
+    "django-datetime": DjangoDatetimeTransform;
+  }
+}
diff --git a/frontend/app/transforms/django-duration.ts b/frontend/app/transforms/django-duration.ts
new file mode 100644
index 000000000..4d0db9033
--- /dev/null
+++ b/frontend/app/transforms/django-duration.ts
@@ -0,0 +1,98 @@
+import Transform from "@ember-data/serializer/transform";
+import moment from "moment";
+import { pad2joincolon } from "timed/utils/pad";
+import parseDjangoDuration from "timed/utils/parse-django-duration";
+
+const { round } = Math;
+
+/**
+ * The django duration transform
+ *
+ * This transforms a django duration into a moment duration
+ *
+ * Django formats the timedelta like this: `DD HH:MM:ss.uuuuuu`. However,
+ * days and microseconds are optional.
+ *
+ * @see http://www.django-rest-framework.org/api-guide/fields/#durationfield
+ * @see https://github.com/django/django/blob/main/django/utils/duration.py
+ *
+ * @class DjangoDurationTransform
+ * @extends DS.Transform
+ * @public
+ */
+export default class DjangoDurationTransform extends Transform {
+  /**
+   * Deserialize the django duration into a moment duration
+   *
+   * @method deserialize
+   * @param {String} serialized The django duration
+   * @return {moment.duration} The deserialized moment duration
+   * @public
+   */
+  deserialize(serialized) {
+    return parseDjangoDuration(serialized);
+  }
+
+  /**
+   * Get the duration components from the duration like pythons timedelta does
+   * it.
+   *
+   * This means that a duration of -1 hour becomes a duration of -1 day +23
+   * hours, so we never have a negative hour, minute, second or millisecond.
+   * ONLY days can be negative!
+   *
+   * @method _getDurationComponentsTimedeltaLike
+   * @param {moment.duration} duration The duration to parse
+   * @returns {Object} An object containing all needed components as number
+   * @private
+   */
+  _getDurationComponentsTimedeltaLike(duration) {
+    const days = Math.floor(duration.asDays());
+    const milliseconds = Math.abs(moment.duration({ days }) - duration);
+
+    const positiveDuration = moment.duration(milliseconds);
+
+    return {
+      days,
+      hours: positiveDuration.hours(),
+      minutes: positiveDuration.minutes(),
+      seconds: positiveDuration.seconds(),
+      microseconds: round(positiveDuration.milliseconds() * 1000),
+    };
+  }
+
+  /**
+   * Serialize the moment duration into a django duration
+   *
+   * @method serialize
+   * @param {moment.duration} deserialized The moment duration
+   * @return {String} The serialized django duration
+   * @public
+   */
+  serialize(deserialized) {
+    if (!moment.isDuration(deserialized)) {
+      return null;
+    }
+
+    const { days, hours, minutes, seconds, microseconds } =
+      this._getDurationComponentsTimedeltaLike(deserialized);
+
+    let string = pad2joincolon(hours, minutes, seconds);
+
+    if (days) {
+      string = `${days} ${string}`;
+    }
+
+    if (microseconds) {
+      string += `.${String(microseconds).padStart(6, "0")}`;
+    }
+
+    return string;
+  }
+}
+
+declare module "ember-data/types/registries/transform" {
+  export default interface TransformRegistry {
+    "django-duration": DjangoDurationTransform;
+  }
+}
diff --git a/frontend/app/transforms/django-time.ts b/frontend/app/transforms/django-time.ts
new file mode 100644
index 000000000..86b26e98c
--- /dev/null
+++ b/frontend/app/transforms/django-time.ts
@@ -0,0 +1,26 @@
+import MomentTransform from "timed/transforms/moment";
+
+/**
+ * The django time transform
+ *
+ * This transforms a django time into a moment object
+ *
+ * @class DjangoTimeTransform
+ * @extends MomentTransform
+ * @public
+ */
+export default class DjangoTimeTransform extends MomentTransform {
+  /**
+   * The time format
+   *
+   * @property {String} format
+   * @public
+   */
+  format = "HH:mm:ss";
+}
+
+declare module "ember-data/types/registries/transform" {
+  export default interface TransformRegistry {
+    "django-time": DjangoTimeTransform;
+  }
+}
diff --git a/frontend/app/transforms/django-workdays.ts b/frontend/app/transforms/django-workdays.ts
new file mode 100644
index 000000000..a31ebb4a8
--- /dev/null
+++ b/frontend/app/transforms/django-workdays.ts
@@ -0,0 +1,42 @@
+import Transform from "@ember-data/serializer/transform";
+
+/**
+ * Django worktime transform
+ *
+ * This transforms a string like '1,2,3' into an array of numbers
+ *
+ * @class DjangoWorktimeTransform
+ * @extends DS.Transform
+ * @public
+ */
+export default class DjangoWorkdaysTransform extends Transform {
+  /**
+   * Deserialize the string separated by comma into an array of numbers
+   *
+   * @method deserialize
+   * @param {String} serialized The string
+   * @return {Number[]} The deserialized array
+   * @public
+   */
+  deserialize(serialized) {
+    return serialized.split(",").map(Number);
+  }
+
+  /**
+   * Serialize the array of numbers into a string separated by comma
+   *
+   * @method serialize
+   * @param {Number[]} deserialized The number array
+   * @return {String} The serialized string
+   * @public
+   */
+  serialize(deserialized) {
+    return deserialized.join();
+  }
+}
+
+declare module "ember-data/types/registries/transform" {
+  export default interface TransformRegistry {
+    "django-workdays": DjangoWorkdaysTransform;
+  }
+}
diff --git a/frontend/app/transforms/moment.ts b/frontend/app/transforms/moment.ts
new file mode 100644
index 000000000..296ce5bca
--- /dev/null
+++ b/frontend/app/transforms/moment.ts
@@ -0,0 +1,53 @@
+import Transform from "@ember-data/serializer/transform";
+import moment from "moment";
+
+/**
+ * The moment transform
+ *
+ * This transforms any string into a moment object
+ *
+ * @class MomentTransform
+ * @extends DS.Transform
+ * @public
+ */
+export default class MomentTransform extends Transform {
+  /**
+   * The default date string format
+   *
+   * @property {String} format
+   * @public
+   */
+  format = moment.defaultFormat;
+
+  /**
+   * Deserialize the string into a moment object
+   *
+   * @method deserialize
+   * @param {String} serialized The date string
+   * @return {moment.duration} The deserialized moment object
+   * @public
+   */
+  deserialize(serialized) {
+    return serialized ? moment(serialized, this.format) : null;
+  }
+
+  /**
+   * Serialize the moment object into a string
+   *
+   * @method serialize
+   * @param {String} deserialized The moment object
+   * @return {moment.duration} The serialized date string
+   * @public
+   */
+  serialize(deserialized) {
+    return deserialized && deserialized.isValid()
+      ? deserialized.format(this.format)
+      : null;
+  }
+}
+
+declare module "ember-data/types/registries/transform" {
+  export default interface TransformRegistry {
+    moment: MomentTransform;
+  }
+}
diff --git a/frontend/types/ember-data/registries/model.d.ts b/frontend/types/ember-data/registries/model.d.ts
index 6ec513ab7..bdd8c0f17 100644
--- a/frontend/types/ember-data/registries/model.d.ts
+++ b/frontend/types/ember-data/registries/model.d.ts
@@ -4,4 +4,4 @@
 export default interface ModelRegistry {
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   [key: string]: any;
-}
\ No newline at end of file
+}
diff --git a/frontend/types/glint.d.ts b/frontend/types/glint.d.ts
index 8fe909340..17bdace04 100644
--- a/frontend/types/glint.d.ts
+++ b/frontend/types/glint.d.ts
@@ -1,12 +1,12 @@
 // Setup Glint Globals
-import '@glint/environment-ember-loose';
-import '@glint/environment-ember-template-imports';
+import "@glint/environment-ember-loose";
+import "@glint/environment-ember-template-imports";
 
-declare module '@glint/environment-ember-loose/registry' {
+declare module "@glint/environment-ember-loose/registry" {
   // Remove this once entries have been added! 👇
   // eslint-disable-next-line @typescript-eslint/no-empty-interface
   export default interface Registry {
     // Add any registry entries from other addons here that your addon itself uses (in non-strict mode templates)
     // See https://typed-ember.gitbook.io/glint/using-glint/ember/using-addons
   }
-}
\ No newline at end of file
+}