# /api/v3/work_packages/{id}/relations
---
get:
  parameters:
  - description: Work package id
    example: '1'
    in: path
    name: id
    required: true
    schema:
      type: integer
  responses:
    '302':
      content:
        text/plain:
          examples:
            response:
              value: 'You are being redirected to /api/v3/relations?involved={work_package_id}'
      description: Found
      headers:
        Location:
          schema:
            type: string
  tags:
  - Work Packages
  description: Lists all relations this work package is involved in.
  operationId: List_relations
  summary: List relations
post:
  parameters:
  - description: Work package id
    example: '1'
    in: path
    name: id
    required: true
    schema:
      type: integer
  responses:
    '201':
      description: Created
      headers: {}
    '400':
      content:
        application/hal+json:
          examples:
            response:
              value:
                _type: Error
                errorIdentifier: urn:openproject-org:api:v3:errors:InvalidRequestBody
                message: The request body was not a single JSON object.
      description: Occurs when the client did not send a valid JSON object in the
        request body.
      headers: {}
    '403':
      content:
        application/hal+json:
          examples:
            response:
              value:
                _type: Error
                errorIdentifier: urn:openproject-org:api:v3:errors:MissingPermission
                message: You are not allowed to create a relation.
      description: |-
        Returned if the client does not have sufficient permissions.

        **Required permission:** manage work package relations
      headers: {}
    '409':
      content:
        application/hal+json:
          examples:
            response:
              value:
                _type: Error
                errorIdentifier: urn:openproject-org:api:v3:errors:UpdateConflict
                message: Couldn't update the resource because of conflicting modifications.
      description: |-
        Returned if there already exists a relation between the given work packages of **any** type
        or if the relation is not allowed.
      headers: {}
    '422':
      content:
        application/hal+json:
          examples:
            response:
              value:
                _embedded:
                  details:
                    attribute: delay
                _type: Error
                errorIdentifier: urn:openproject-org:api:v3:errors:PropertyConstraintViolation
                message: Delay must be a number greater than or equal to 0
      description: |-
        Returned if:

        * the client tries to write a read-only property (`PropertyIsReadOnly`)

        * a constraint for a property was violated (`PropertyConstraintViolation`)

        * the client provides a link to an invalid resource (`ResourceTypeMismatch`)
      headers: {}
  tags:
  - Work Packages
  description: |-
    When calling this endpoint the client provides a single object, containing at least the properties and links that are required, in the body.
    The required fields of a Relation can be found in its schema, which is embedded in the respective form.
    Note that it is only allowed to provide properties or links supporting the write operation.
  operationId: Create_Relation
  summary: Create Relation