diff --git a/x-pack/plugins/cases/docs/openapi/bundled.json b/x-pack/plugins/cases/docs/openapi/bundled.json
index c3fef89e021dd..b36a745179833 100644
--- a/x-pack/plugins/cases/docs/openapi/bundled.json
+++ b/x-pack/plugins/cases/docs/openapi/bundled.json
@@ -4579,6 +4579,54 @@
         ],
         "default": "low"
       },
+      "custom_fields_property": {
+        "type": "array",
+        "description": "Values for custom fields of a case",
+        "minItems": 0,
+        "maxItems": 5,
+        "items": {
+          "type": "object",
+          "required": [
+            "key",
+            "type",
+            "field"
+          ],
+          "properties": {
+            "key": {
+              "description": "The key identifying the custom field.",
+              "type": "string"
+            },
+            "type": {
+              "description": "The type of the custom field. Should match the key and how the custom field was configured",
+              "type": "string"
+            },
+            "field": {
+              "description": "An object containing the value of the field.",
+              "type": "object",
+              "required": [
+                "value"
+              ],
+              "properties": {
+                "value": {
+                  "description": "The value of the field.",
+                  "nullable": true,
+                  "type": "array",
+                  "items": {
+                    "anyOf": [
+                      {
+                        "type": "string"
+                      },
+                      {
+                        "type": "boolean"
+                      }
+                    ]
+                  }
+                }
+              }
+            }
+          }
+        }
+      },
       "create_case_request": {
         "title": "Create case request",
         "description": "The create case API request body varies depending on the type of connector.",
@@ -4652,6 +4700,9 @@
             "description": "A title for the case.",
             "type": "string",
             "maxLength": 160
+          },
+          "customFields": {
+            "$ref": "#/components/schemas/custom_fields_property"
           }
         }
       },
@@ -5296,6 +5347,9 @@
                 "version": {
                   "description": "The current version of the case. To determine this value, use the get case or find cases APIs.",
                   "type": "string"
+                },
+                "customFields": {
+                  "$ref": "#/components/schemas/custom_fields_property"
                 }
               }
             }
diff --git a/x-pack/plugins/cases/docs/openapi/bundled.yaml b/x-pack/plugins/cases/docs/openapi/bundled.yaml
index f818d279a2e27..ddee756120e01 100644
--- a/x-pack/plugins/cases/docs/openapi/bundled.yaml
+++ b/x-pack/plugins/cases/docs/openapi/bundled.yaml
@@ -2890,6 +2890,38 @@ components:
         - low
         - medium
       default: low
+    custom_fields_property:
+      type: array
+      description: Values for custom fields of a case
+      minItems: 0
+      maxItems: 5
+      items:
+        type: object
+        required:
+          - key
+          - type
+          - field
+        properties:
+          key:
+            description: The key identifying the custom field.
+            type: string
+          type:
+            description: The type of the custom field. Should match the key and how the custom field was configured
+            type: string
+          field:
+            description: An object containing the value of the field.
+            type: object
+            required:
+              - value
+            properties:
+              value:
+                description: The value of the field.
+                nullable: true
+                type: array
+                items:
+                  anyOf:
+                    - type: string
+                    - type: boolean
     create_case_request:
       title: Create case request
       description: The create case API request body varies depending on the type of connector.
@@ -2938,6 +2970,8 @@ components:
           description: A title for the case.
           type: string
           maxLength: 160
+        customFields:
+          $ref: '#/components/schemas/custom_fields_property'
     case_response_closed_by_properties:
       title: Case response properties for closed_by
       type: object
@@ -3403,6 +3437,8 @@ components:
               version:
                 description: The current version of the case. To determine this value, use the get case or find cases APIs.
                 type: string
+              customFields:
+                $ref: '#/components/schemas/custom_fields_property'
     searchFieldsType:
       type: string
       description: The fields to perform the `simple_query_string` parsed query against.
diff --git a/x-pack/plugins/cases/docs/openapi/components/schemas/create_case_request.yaml b/x-pack/plugins/cases/docs/openapi/components/schemas/create_case_request.yaml
index 1092975985dd0..7b3d8d8219ff7 100644
--- a/x-pack/plugins/cases/docs/openapi/components/schemas/create_case_request.yaml
+++ b/x-pack/plugins/cases/docs/openapi/components/schemas/create_case_request.yaml
@@ -3,12 +3,12 @@ description: >-
   The create case API request body varies depending on the type of connector.
 type: object
 required:
-      - connector
-      - description
-      - owner
-      - settings
-      - tags
-      - title
+  - connector
+  - description
+  - owner
+  - settings
+  - tags
+  - title
 properties:
   assignees:
     $ref: 'assignees.yaml'
@@ -45,4 +45,6 @@ properties:
   title:
     description: A title for the case.
     type: string
-    maxLength: 160
\ No newline at end of file
+    maxLength: 160
+  customFields:
+    $ref: 'custom_fields_property.yaml'
diff --git a/x-pack/plugins/cases/docs/openapi/components/schemas/custom_fields_property.yaml b/x-pack/plugins/cases/docs/openapi/components/schemas/custom_fields_property.yaml
new file mode 100644
index 0000000000000..2b682960bd1f0
--- /dev/null
+++ b/x-pack/plugins/cases/docs/openapi/components/schemas/custom_fields_property.yaml
@@ -0,0 +1,31 @@
+type: array
+description: Values for custom fields of a case
+minItems: 0
+maxItems: 5
+items:
+  type: object
+  required:
+    - key
+    - type
+    - field
+  properties:
+    key:
+      description: The key identifying the custom field.
+      type: string
+    type:
+      description: The type of the custom field. Should match the key and how the custom field was configured
+      type: string
+    field:
+      description: An object containing the value of the field.
+      type: object
+      required:
+        - value
+      properties:
+        value:
+          description: The value of the field.
+          nullable: true
+          type: array
+          items:
+            anyOf:
+              - type: string
+              - type: boolean
diff --git a/x-pack/plugins/cases/docs/openapi/components/schemas/update_case_request.yaml b/x-pack/plugins/cases/docs/openapi/components/schemas/update_case_request.yaml
index df3e7ab17d674..4bbac95630e47 100644
--- a/x-pack/plugins/cases/docs/openapi/components/schemas/update_case_request.yaml
+++ b/x-pack/plugins/cases/docs/openapi/components/schemas/update_case_request.yaml
@@ -58,3 +58,5 @@ properties:
         version:
           description: The current version of the case. To determine this value, use the get case or find cases APIs.
           type: string
+        customFields:
+          $ref: 'custom_fields_property.yaml'