diff --git a/marklogic-data-hub-central/src/main/java/com/marklogic/hub/central/controllers/steps/MappingStepController.java b/marklogic-data-hub-central/src/main/java/com/marklogic/hub/central/controllers/steps/MappingStepController.java
index e7c2a9e3d3..6050283624 100644
--- a/marklogic-data-hub-central/src/main/java/com/marklogic/hub/central/controllers/steps/MappingStepController.java
+++ b/marklogic-data-hub-central/src/main/java/com/marklogic/hub/central/controllers/steps/MappingStepController.java
@@ -3,7 +3,7 @@
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.marklogic.hub.central.controllers.BaseController;
-import com.marklogic.hub.central.schemas.StepSchema;
+import com.marklogic.hub.central.schemas.MappingStepSchema;
 import com.marklogic.hub.dataservices.ArtifactService;
 import com.marklogic.hub.dataservices.MappingService;
 import com.marklogic.hub.dataservices.StepService;
@@ -35,14 +35,14 @@ public ResponseEntity<JsonNode> getSteps() {
     }
 
     @RequestMapping(value = "/{stepName}", method = RequestMethod.GET)
-    @ApiOperation(value = "Get a step", response = StepSchema.class)
+    @ApiOperation(value = "Get a step", response = MappingStepSchema.class)
     @Secured("ROLE_readMapping")
     public ResponseEntity<JsonNode> getStep(@PathVariable String stepName) {
         return ResponseEntity.ok(newService().getStep(STEP_DEFINITION_TYPE, stepName));
     }
 
     @RequestMapping(method = RequestMethod.POST)
-    @ApiImplicitParam(required = true, paramType = "body", dataType = "StepSchema")
+    @ApiImplicitParam(required = true, paramType = "body", dataType = "MappingStepSchema")
     @Secured("ROLE_writeMapping")
     public ResponseEntity<Void> createMappingStep(@RequestBody @ApiParam(hidden = true) ObjectNode propertiesToAssign) {
         String stepName = propertiesToAssign.get("name").asText();
@@ -52,7 +52,7 @@ public ResponseEntity<Void> createMappingStep(@RequestBody @ApiParam(hidden = tr
     }
 
     @RequestMapping(value = "/{stepName}", method = RequestMethod.PUT)
-    @ApiImplicitParam(required = true, paramType = "body", dataType = "StepSchema")
+    @ApiImplicitParam(required = true, paramType = "body", dataType = "MappingStepSchema")
     @Secured("ROLE_writeMapping")
     public ResponseEntity<Void> updateMappingStep(@RequestBody @ApiParam(hidden = true) ObjectNode propertiesToAssign, @PathVariable String stepName) {
         propertiesToAssign.put("name", stepName);
@@ -102,7 +102,7 @@ private StepService newService() {
         return StepService.on(getHubClient().getStagingClient());
     }
 
-    public static class MappingSteps extends ArrayList<StepSchema> {
+    public static class MappingSteps extends ArrayList<MappingStepSchema> {
     }
 
 }
diff --git a/marklogic-data-hub-central/src/main/java/com/marklogic/hub/central/schemas/MappingPropertiesSchema.java b/marklogic-data-hub-central/src/main/java/com/marklogic/hub/central/schemas/MappingPropertiesSchema.java
new file mode 100644
index 0000000000..1480ad6af8
--- /dev/null
+++ b/marklogic-data-hub-central/src/main/java/com/marklogic/hub/central/schemas/MappingPropertiesSchema.java
@@ -0,0 +1,51 @@
+
+package com.marklogic.hub.central.schemas;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+
+/**
+ * MappingProperties
+ * <p>
+ * 
+ * 
+ */
+@JsonInclude(JsonInclude.Include.NON_NULL)
+@JsonPropertyOrder({
+
+})
+public class MappingPropertiesSchema {
+
+
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        sb.append(MappingPropertiesSchema.class.getName()).append('@').append(Integer.toHexString(System.identityHashCode(this))).append('[');
+        if (sb.charAt((sb.length()- 1)) == ',') {
+            sb.setCharAt((sb.length()- 1), ']');
+        } else {
+            sb.append(']');
+        }
+        return sb.toString();
+    }
+
+    @Override
+    public int hashCode() {
+        int result = 1;
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (other == this) {
+            return true;
+        }
+        if ((other instanceof MappingPropertiesSchema) == false) {
+            return false;
+        }
+        MappingPropertiesSchema rhs = ((MappingPropertiesSchema) other);
+        return true;
+    }
+
+}
diff --git a/marklogic-data-hub-central/src/main/java/com/marklogic/hub/central/schemas/MappingStepSchema.java b/marklogic-data-hub-central/src/main/java/com/marklogic/hub/central/schemas/MappingStepSchema.java
new file mode 100644
index 0000000000..f8ecbfde14
--- /dev/null
+++ b/marklogic-data-hub-central/src/main/java/com/marklogic/hub/central/schemas/MappingStepSchema.java
@@ -0,0 +1,143 @@
+
+package com.marklogic.hub.central.schemas;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonPropertyDescription;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+
+/**
+ * MappingStep
+ * <p>
+ * 
+ * 
+ */
+@JsonInclude(JsonInclude.Include.NON_NULL)
+@JsonPropertyOrder({
+    "properties",
+    "relatedEntityMappings"
+})
+public class MappingStepSchema {
+
+    /**
+     * MappingProperties
+     * <p>
+     * 
+     * 
+     */
+    @JsonProperty("properties")
+    private MappingPropertiesSchema properties;
+    /**
+     * additional collections provided by the user that get applied to the step output
+     * 
+     */
+    @JsonProperty("relatedEntityMappings")
+    @JsonPropertyDescription("additional collections provided by the user that get applied to the step output")
+    private List<RelatedEntityMapping> relatedEntityMappings = new ArrayList<RelatedEntityMapping>();
+    @JsonIgnore
+    private Map<String, Object> additionalProperties = new HashMap<String, Object>();
+
+    /**
+     * MappingProperties
+     * <p>
+     * 
+     * 
+     */
+    @JsonProperty("properties")
+    public MappingPropertiesSchema getProperties() {
+        return properties;
+    }
+
+    /**
+     * MappingProperties
+     * <p>
+     * 
+     * 
+     */
+    @JsonProperty("properties")
+    public void setProperties(MappingPropertiesSchema properties) {
+        this.properties = properties;
+    }
+
+    /**
+     * additional collections provided by the user that get applied to the step output
+     * 
+     */
+    @JsonProperty("relatedEntityMappings")
+    public List<RelatedEntityMapping> getRelatedEntityMappings() {
+        return relatedEntityMappings;
+    }
+
+    /**
+     * additional collections provided by the user that get applied to the step output
+     * 
+     */
+    @JsonProperty("relatedEntityMappings")
+    public void setRelatedEntityMappings(List<RelatedEntityMapping> relatedEntityMappings) {
+        this.relatedEntityMappings = relatedEntityMappings;
+    }
+
+    @JsonAnyGetter
+    public Map<String, Object> getAdditionalProperties() {
+        return this.additionalProperties;
+    }
+
+    @JsonAnySetter
+    public void setAdditionalProperty(String name, Object value) {
+        this.additionalProperties.put(name, value);
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        sb.append(MappingStepSchema.class.getName()).append('@').append(Integer.toHexString(System.identityHashCode(this))).append('[');
+        sb.append("properties");
+        sb.append('=');
+        sb.append(((this.properties == null)?"<null>":this.properties));
+        sb.append(',');
+        sb.append("relatedEntityMappings");
+        sb.append('=');
+        sb.append(((this.relatedEntityMappings == null)?"<null>":this.relatedEntityMappings));
+        sb.append(',');
+        sb.append("additionalProperties");
+        sb.append('=');
+        sb.append(((this.additionalProperties == null)?"<null>":this.additionalProperties));
+        sb.append(',');
+        if (sb.charAt((sb.length()- 1)) == ',') {
+            sb.setCharAt((sb.length()- 1), ']');
+        } else {
+            sb.append(']');
+        }
+        return sb.toString();
+    }
+
+    @Override
+    public int hashCode() {
+        int result = 1;
+        result = ((result* 31)+((this.relatedEntityMappings == null)? 0 :this.relatedEntityMappings.hashCode()));
+        result = ((result* 31)+((this.additionalProperties == null)? 0 :this.additionalProperties.hashCode()));
+        result = ((result* 31)+((this.properties == null)? 0 :this.properties.hashCode()));
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (other == this) {
+            return true;
+        }
+        if ((other instanceof MappingStepSchema) == false) {
+            return false;
+        }
+        MappingStepSchema rhs = ((MappingStepSchema) other);
+        return ((((this.relatedEntityMappings == rhs.relatedEntityMappings)||((this.relatedEntityMappings!= null)&&this.relatedEntityMappings.equals(rhs.relatedEntityMappings)))&&((this.additionalProperties == rhs.additionalProperties)||((this.additionalProperties!= null)&&this.additionalProperties.equals(rhs.additionalProperties))))&&((this.properties == rhs.properties)||((this.properties!= null)&&this.properties.equals(rhs.properties))));
+    }
+
+}
diff --git a/marklogic-data-hub-central/src/main/java/com/marklogic/hub/central/schemas/RelatedEntityMapping.java b/marklogic-data-hub-central/src/main/java/com/marklogic/hub/central/schemas/RelatedEntityMapping.java
new file mode 100644
index 0000000000..5ab0d67023
--- /dev/null
+++ b/marklogic-data-hub-central/src/main/java/com/marklogic/hub/central/schemas/RelatedEntityMapping.java
@@ -0,0 +1,300 @@
+
+package com.marklogic.hub.central.schemas;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonPropertyDescription;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+@JsonInclude(JsonInclude.Include.NON_NULL)
+@JsonPropertyOrder({
+    "relatedEntityMappingId",
+    "expressionContext",
+    "uriExpression",
+    "properties",
+    "collections",
+    "permissions",
+    "targetEntityType"
+})
+public class RelatedEntityMapping {
+
+    /**
+     * Unique identifier of the related entity mapping
+     * (Required)
+     * 
+     */
+    @JsonProperty("relatedEntityMappingId")
+    @JsonPropertyDescription("Unique identifier of the related entity mapping")
+    private String relatedEntityMappingId;
+    /**
+     * An element in the source data from which to derive the values of this related entity's properties
+     * 
+     */
+    @JsonProperty("expressionContext")
+    @JsonPropertyDescription("An element in the source data from which to derive the values of this related entity's properties")
+    private String expressionContext;
+    /**
+     * XPath expression for generating the uri of this related entity instance document
+     * 
+     */
+    @JsonProperty("uriExpression")
+    @JsonPropertyDescription("XPath expression for generating the uri of this related entity instance document")
+    private String uriExpression;
+    /**
+     * MappingProperties
+     * <p>
+     * 
+     * (Required)
+     * 
+     */
+    @JsonProperty("properties")
+    private MappingPropertiesSchema properties;
+    /**
+     * additional collections provided by the user that get applied to this related entity instance document
+     * 
+     */
+    @JsonProperty("collections")
+    @JsonPropertyDescription("additional collections provided by the user that get applied to this related entity instance document")
+    private List<String> collections = new ArrayList<String>();
+    /**
+     * Comma-delimited string of role,capability,role,capability,etc for the entity instance generated by this mapping
+     * 
+     */
+    @JsonProperty("permissions")
+    @JsonPropertyDescription("Comma-delimited string of role,capability,role,capability,etc for the entity instance generated by this mapping")
+    private String permissions;
+    /**
+     * The identifier of the related Entity Type. (IRI, with title as fallback)
+     * (Required)
+     * 
+     */
+    @JsonProperty("targetEntityType")
+    @JsonPropertyDescription("The identifier of the related Entity Type. (IRI, with title as fallback)")
+    private String targetEntityType;
+    @JsonIgnore
+    private Map<String, Object> additionalProperties = new HashMap<String, Object>();
+
+    /**
+     * Unique identifier of the related entity mapping
+     * (Required)
+     * 
+     */
+    @JsonProperty("relatedEntityMappingId")
+    public String getRelatedEntityMappingId() {
+        return relatedEntityMappingId;
+    }
+
+    /**
+     * Unique identifier of the related entity mapping
+     * (Required)
+     * 
+     */
+    @JsonProperty("relatedEntityMappingId")
+    public void setRelatedEntityMappingId(String relatedEntityMappingId) {
+        this.relatedEntityMappingId = relatedEntityMappingId;
+    }
+
+    /**
+     * An element in the source data from which to derive the values of this related entity's properties
+     * 
+     */
+    @JsonProperty("expressionContext")
+    public String getExpressionContext() {
+        return expressionContext;
+    }
+
+    /**
+     * An element in the source data from which to derive the values of this related entity's properties
+     * 
+     */
+    @JsonProperty("expressionContext")
+    public void setExpressionContext(String expressionContext) {
+        this.expressionContext = expressionContext;
+    }
+
+    /**
+     * XPath expression for generating the uri of this related entity instance document
+     * 
+     */
+    @JsonProperty("uriExpression")
+    public String getUriExpression() {
+        return uriExpression;
+    }
+
+    /**
+     * XPath expression for generating the uri of this related entity instance document
+     * 
+     */
+    @JsonProperty("uriExpression")
+    public void setUriExpression(String uriExpression) {
+        this.uriExpression = uriExpression;
+    }
+
+    /**
+     * MappingProperties
+     * <p>
+     * 
+     * (Required)
+     * 
+     */
+    @JsonProperty("properties")
+    public MappingPropertiesSchema getProperties() {
+        return properties;
+    }
+
+    /**
+     * MappingProperties
+     * <p>
+     * 
+     * (Required)
+     * 
+     */
+    @JsonProperty("properties")
+    public void setProperties(MappingPropertiesSchema properties) {
+        this.properties = properties;
+    }
+
+    /**
+     * additional collections provided by the user that get applied to this related entity instance document
+     * 
+     */
+    @JsonProperty("collections")
+    public List<String> getCollections() {
+        return collections;
+    }
+
+    /**
+     * additional collections provided by the user that get applied to this related entity instance document
+     * 
+     */
+    @JsonProperty("collections")
+    public void setCollections(List<String> collections) {
+        this.collections = collections;
+    }
+
+    /**
+     * Comma-delimited string of role,capability,role,capability,etc for the entity instance generated by this mapping
+     * 
+     */
+    @JsonProperty("permissions")
+    public String getPermissions() {
+        return permissions;
+    }
+
+    /**
+     * Comma-delimited string of role,capability,role,capability,etc for the entity instance generated by this mapping
+     * 
+     */
+    @JsonProperty("permissions")
+    public void setPermissions(String permissions) {
+        this.permissions = permissions;
+    }
+
+    /**
+     * The identifier of the related Entity Type. (IRI, with title as fallback)
+     * (Required)
+     * 
+     */
+    @JsonProperty("targetEntityType")
+    public String getTargetEntityType() {
+        return targetEntityType;
+    }
+
+    /**
+     * The identifier of the related Entity Type. (IRI, with title as fallback)
+     * (Required)
+     * 
+     */
+    @JsonProperty("targetEntityType")
+    public void setTargetEntityType(String targetEntityType) {
+        this.targetEntityType = targetEntityType;
+    }
+
+    @JsonAnyGetter
+    public Map<String, Object> getAdditionalProperties() {
+        return this.additionalProperties;
+    }
+
+    @JsonAnySetter
+    public void setAdditionalProperty(String name, Object value) {
+        this.additionalProperties.put(name, value);
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        sb.append(RelatedEntityMapping.class.getName()).append('@').append(Integer.toHexString(System.identityHashCode(this))).append('[');
+        sb.append("relatedEntityMappingId");
+        sb.append('=');
+        sb.append(((this.relatedEntityMappingId == null)?"<null>":this.relatedEntityMappingId));
+        sb.append(',');
+        sb.append("expressionContext");
+        sb.append('=');
+        sb.append(((this.expressionContext == null)?"<null>":this.expressionContext));
+        sb.append(',');
+        sb.append("uriExpression");
+        sb.append('=');
+        sb.append(((this.uriExpression == null)?"<null>":this.uriExpression));
+        sb.append(',');
+        sb.append("properties");
+        sb.append('=');
+        sb.append(((this.properties == null)?"<null>":this.properties));
+        sb.append(',');
+        sb.append("collections");
+        sb.append('=');
+        sb.append(((this.collections == null)?"<null>":this.collections));
+        sb.append(',');
+        sb.append("permissions");
+        sb.append('=');
+        sb.append(((this.permissions == null)?"<null>":this.permissions));
+        sb.append(',');
+        sb.append("targetEntityType");
+        sb.append('=');
+        sb.append(((this.targetEntityType == null)?"<null>":this.targetEntityType));
+        sb.append(',');
+        sb.append("additionalProperties");
+        sb.append('=');
+        sb.append(((this.additionalProperties == null)?"<null>":this.additionalProperties));
+        sb.append(',');
+        if (sb.charAt((sb.length()- 1)) == ',') {
+            sb.setCharAt((sb.length()- 1), ']');
+        } else {
+            sb.append(']');
+        }
+        return sb.toString();
+    }
+
+    @Override
+    public int hashCode() {
+        int result = 1;
+        result = ((result* 31)+((this.collections == null)? 0 :this.collections.hashCode()));
+        result = ((result* 31)+((this.targetEntityType == null)? 0 :this.targetEntityType.hashCode()));
+        result = ((result* 31)+((this.permissions == null)? 0 :this.permissions.hashCode()));
+        result = ((result* 31)+((this.relatedEntityMappingId == null)? 0 :this.relatedEntityMappingId.hashCode()));
+        result = ((result* 31)+((this.expressionContext == null)? 0 :this.expressionContext.hashCode()));
+        result = ((result* 31)+((this.additionalProperties == null)? 0 :this.additionalProperties.hashCode()));
+        result = ((result* 31)+((this.uriExpression == null)? 0 :this.uriExpression.hashCode()));
+        result = ((result* 31)+((this.properties == null)? 0 :this.properties.hashCode()));
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (other == this) {
+            return true;
+        }
+        if ((other instanceof RelatedEntityMapping) == false) {
+            return false;
+        }
+        RelatedEntityMapping rhs = ((RelatedEntityMapping) other);
+        return (((((((((this.collections == rhs.collections)||((this.collections!= null)&&this.collections.equals(rhs.collections)))&&((this.targetEntityType == rhs.targetEntityType)||((this.targetEntityType!= null)&&this.targetEntityType.equals(rhs.targetEntityType))))&&((this.permissions == rhs.permissions)||((this.permissions!= null)&&this.permissions.equals(rhs.permissions))))&&((this.relatedEntityMappingId == rhs.relatedEntityMappingId)||((this.relatedEntityMappingId!= null)&&this.relatedEntityMappingId.equals(rhs.relatedEntityMappingId))))&&((this.expressionContext == rhs.expressionContext)||((this.expressionContext!= null)&&this.expressionContext.equals(rhs.expressionContext))))&&((this.additionalProperties == rhs.additionalProperties)||((this.additionalProperties!= null)&&this.additionalProperties.equals(rhs.additionalProperties))))&&((this.uriExpression == rhs.uriExpression)||((this.uriExpression!= null)&&this.uriExpression.equals(rhs.uriExpression))))&&((this.properties == rhs.properties)||((this.properties!= null)&&this.properties.equals(rhs.properties))));
+    }
+
+}
diff --git a/specs/models/MappingProperties.schema.json b/specs/models/MappingProperties.schema.json
new file mode 100644
index 0000000000..083bfff1ab
--- /dev/null
+++ b/specs/models/MappingProperties.schema.json
@@ -0,0 +1,22 @@
+{
+  "title": "MappingProperties",
+  "type": "object",
+  "additionalProperties": false,
+  "patternProperties": {
+    "^[a-zA-Z0-9]+$": {
+      "type": "object",
+      "properties": {
+        "sourcedFrom": {
+          "type": "string"
+        },
+        "targetEntityType": {
+          "type": "string"
+        },
+        "properties": {
+          "$ref": "#"
+        }
+      },
+      "required": ["sourcedFrom"]
+    }
+  }
+}
diff --git a/specs/models/MappingStep.schema.json b/specs/models/MappingStep.schema.json
new file mode 100644
index 0000000000..99ded1a57e
--- /dev/null
+++ b/specs/models/MappingStep.schema.json
@@ -0,0 +1,53 @@
+{
+  "title": "MappingStep",
+  "id": "http://marklogic.com/data-hub/MappingStep.schema.json",
+  "allOf": [{ "$ref": "http://marklogic.com/data-hub/Step.schema.json" }],
+  "type": "object",
+  "properties": {
+    "properties": {
+      "type": "object",
+      "$ref": "./MappingProperties.schema.json"
+    },
+    "relatedEntityMappings": {
+      "type":  "array",
+      "description": "additional collections provided by the user that get applied to the step output",
+      "items": {
+        "type": "object",
+        "properties": {
+          "relatedEntityMappingId": {
+            "type": "string",
+            "description": "Unique identifier of the related entity mapping"
+          },
+          "expressionContext": {
+            "type":  "string",
+            "description": "An element in the source data from which to derive the values of this related entity's properties"
+          },
+          "uriExpression": {
+            "type":  "string",
+            "description": "XPath expression for generating the uri of this related entity instance document"
+          },
+          "properties": {
+            "type": "object",
+            "$ref": "./MappingProperties.schema.json"
+          },
+          "collections": {
+            "type": "array",
+            "items": {
+              "type": "string"
+            },
+            "description": "additional collections provided by the user that get applied to this related entity instance document"
+          },
+          "permissions": {
+            "type": "string",
+            "description": "Comma-delimited string of role,capability,role,capability,etc for the entity instance generated by this mapping"
+          },
+          "targetEntityType": {
+            "type": "string",
+            "description": "The identifier of the related Entity Type. (IRI, with title as fallback)"
+          }
+        },
+        "required": ["relatedEntityMappingId", "properties", "targetEntityType"]
+      }
+    }
+  }
+}
diff --git a/specs/models/Step.schema.json b/specs/models/Step.schema.json
index 14dae91b8c..7dcb46989a 100644
--- a/specs/models/Step.schema.json
+++ b/specs/models/Step.schema.json
@@ -1,5 +1,6 @@
 {
   "title": "Step",
+  "id": "http://marklogic.com/data-hub/Step.schema.json",
   "type": "object",
   "properties": {
     "interceptors": {