> ## Documentation Index
> Fetch the complete documentation index at: https://docs.closient.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Record an accepted return of a serialized unit

> Record that the return desk accepted a unit back. Writes a GS1 CBV 2.0 EPCIS ``ObjectEvent`` (action ``OBSERVE``, bizStep ``receiving``, disposition ``returned``) through the same capture pipeline as ``/capture``, so the event is retrievable from ``/events`` and the next ``/verification/serial`` call for the unit answers ``already_returned`` with this return's time.

**A unit is returned once.** A second return of a unit whose latest state is ``returned`` is refused with ``409`` naming the earlier return's time, and is counted as an ``already_returned`` attempt in the verification report. Two returns racing on one unit produce exactly one event. A unit that is sold again after a return can be returned again.

``404`` if this organization has no events for the GTIN + serial: a return is recorded against the unit's own history, never another organization's. Caller must hold an OWNER or MANAGER membership on the organization.



## OpenAPI

````yaml /openapi/openapi-epcis.json post /epcis/api/2.0/verification/returns
openapi: 3.1.0
info:
  title: EPCIS 2.0 API
  version: 2.0.0
  description: >
    EPCIS 2.0 event capture and query, scoped to lot-level supply chain
    traceability and recall containment — not warehouse logistics, cold-chain
    monitoring, or business-document exchange.


    Roles claimed: EPCIS 2.0 capture interface server, EPCIS 2.0 data. Not
    claimed: EPCIS 2.0 query interface server; Query callback interface
    implementation.


    Binding: REST over HTTPS. Serialization: JSON and JSON-LD. Vocabulary: GS1
    CBV 2.0. XML and EPCIS 1.2 are out of scope by design, not a pending
    decision.


    30 of 63 official EPCIS 2.0 REST operations are served, all within the roles
    claimed above. Full capability declaration:
    https://docs.closient.com/guides/epcis-conformance


    ## Authentication


    All endpoints require an API key passed via the `X-API-Key` HTTP header,
    unless otherwise noted.


    ```

    X-API-Key: csb_<body>_<checksum>

    ```


    Generate API keys in **Settings > API Keys** in your dashboard, or via the
    Account API.

    Session-based (cookie) authentication is also accepted for browser-based
    access.


    ## Rate Limits


    | Tier        | Requests / minute | Requests / day |

    |-------------|-------------------|----------------|

    | Default     | 300               | 10,000         |

    | Custom      | Contact us        | Contact us     |


    Rate-limit headers are included on every response so callers can
    self-throttle without

    hitting our 429s ("informed governor"):


    - `RateLimit-Policy` — every active window, e.g. `300;w=60, 10000;w=86400`

    - `RateLimit-Limit` — quota for the **most-restrictive** currently-active
    window

    - `RateLimit-Remaining` — requests left in that window

    - `RateLimit-Reset` — seconds until that window resets (relative; clock-skew
    safe)


    Legacy `X-RateLimit-*` aliases are also emitted for back-compat.
    `X-RateLimit-Reset`

    keeps the absolute Unix-timestamp shape to avoid breaking existing
    consumers.


    When rate-limited, you receive `429 Too Many Requests` with a
    `retry_after_seconds` field

    in the error envelope and a `Retry-After` header.


    ## Pagination


    List endpoints return paginated results in this envelope:


    ```json

    {
      "data": [...],
      "pagination": {
        "page": 1,
        "page_size": 25,
        "total_count": 342,
        "total_pages": 14,
        "has_next": true,
        "has_previous": false
      }
    }

    ```


    Use `?page=2&page_size=50` query parameters. Maximum page size is 100.


    ## Error Responses


    All errors conform to [RFC 9457 Problem
    Details](https://www.rfc-editor.org/rfc/rfc9457)

    with `Content-Type: application/problem+json`:


    ```json

    {
      "type": "https://closient.com/docs/errors/not_found",
      "title": "Not Found",
      "status": 404,
      "detail": "The requested resource was not found.",
      "error_code": "not_found",
      "retryable": false,
      "timestamp": "2026-03-31T12:00:00+00:00"
    }

    ```


    Common error codes: `unauthorized` (401), `forbidden` (403), `not_found`
    (404),

    `validation_error` (422), `rate_limited` (429), `internal_error` (500).
  termsOfService: https://www.closient.com/terms/
servers:
  - url: https://www.closient.com
security: []
externalDocs:
  description: Closient Documentation
  url: https://docs.closient.com
paths:
  /epcis/api/2.0/verification/returns:
    post:
      tags:
        - EPCIS 2.0
      summary: Record an accepted return of a serialized unit
      description: >-
        Record that the return desk accepted a unit back. Writes a GS1 CBV 2.0
        EPCIS ``ObjectEvent`` (action ``OBSERVE``, bizStep ``receiving``,
        disposition ``returned``) through the same capture pipeline as
        ``/capture``, so the event is retrievable from ``/events`` and the next
        ``/verification/serial`` call for the unit answers ``already_returned``
        with this return's time.


        **A unit is returned once.** A second return of a unit whose latest
        state is ``returned`` is refused with ``409`` naming the earlier
        return's time, and is counted as an ``already_returned`` attempt in the
        verification report. Two returns racing on one unit produce exactly one
        event. A unit that is sold again after a return can be returned again.


        ``404`` if this organization has no events for the GTIN + serial: a
        return is recorded against the unit's own history, never another
        organization's. Caller must hold an OWNER or MANAGER membership on the
        organization.
      operationId: epcis_capture_return
      parameters: []
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/ReturnCaptureIn'
        required: true
      responses:
        '201':
          description: Created
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/CapturedReturnSchema'
        '400':
          description: Bad Request
          content:
            application/problem+json:
              schema:
                $ref: '#/components/schemas/ErrorOut'
        '401':
          description: Unauthorized
          content:
            application/problem+json:
              schema:
                $ref: '#/components/schemas/ErrorOut'
        '402':
          description: Payment Required
          content:
            application/problem+json:
              schema:
                $ref: '#/components/schemas/ErrorOut'
        '403':
          description: Forbidden
          content:
            application/problem+json:
              schema:
                $ref: '#/components/schemas/ErrorOut'
        '404':
          description: Not Found
          content:
            application/problem+json:
              schema:
                $ref: '#/components/schemas/ErrorOut'
        '405':
          description: Method Not Allowed
          content:
            application/problem+json:
              schema:
                $ref: '#/components/schemas/ErrorOut'
        '409':
          description: Conflict
          content:
            application/problem+json:
              schema:
                $ref: '#/components/schemas/ErrorOut'
        '422':
          description: Unprocessable Content
          content:
            application/problem+json:
              schema:
                $ref: '#/components/schemas/ErrorOut'
        '429':
          description: Too Many Requests
          content:
            application/problem+json:
              schema:
                $ref: '#/components/schemas/ErrorOut'
      security:
        - APIKeyHeaderAuth: []
        - OAuthTokenAuth: []
        - CookieGatedSessionAuth: []
components:
  schemas:
    ReturnCaptureIn:
      description: An accepted return of one serialized unit.
      examples:
        - biz_location: urn:epc:id:sgln:0614141.00888.0
          gtin: '00614524740108'
          return_reference: RMA-55102
          serial: ABC123XYZ
      properties:
        gtin:
          description: >-
            GTIN-8/12/13/14 of the returned unit. Normalized to GTIN-14; check
            digit is validated.
          format: gtin
          pattern: ^[0-9]{8}$|^[0-9]{12,14}$
          title: Gtin
          type: string
        serial:
          description: GS1 AI(21) serial number of the returned unit.
          maxLength: 255
          minLength: 1
          pattern: ^[^\x00]{1,255}$
          title: Serial
          type: string
        event_time:
          anyOf:
            - format: date-time
              type: string
            - type: 'null'
          description: >-
            When the return was accepted. Defaults to the time of the request;
            one earlier than the unit's latest recorded event is refused with
            ``422``.
          title: Event Time
        biz_location:
          anyOf:
            - maxLength: 255
              minLength: 1
              pattern: ^[^\x00]{1,255}$
              type: string
            - type: 'null'
          description: >-
            EPCIS ``bizLocation`` of the return desk (an SGLN URN or Digital
            Link URI).
          title: Biz Location
        return_reference:
          anyOf:
            - maxLength: 255
              minLength: 1
              pattern: ^[^\x00]{1,255}$
              type: string
            - type: 'null'
          description: >-
            Return authorization identifier, recorded as an ``rma`` business
            transaction on the event.
          title: Return Reference
      required:
        - gtin
        - serial
      title: ReturnCaptureIn
      type: object
    CapturedReturnSchema:
      description: The return event just recorded.
      examples:
        - event_id: urn:uuid:3f1c2d4e-5a6b-4c7d-8e9f-0a1b2c3d4e5f
          gtin: '00614524740108'
          lot: L2847
          returned_at: '2026-07-20T09:12:00Z'
          sale_transaction_reference: TXN-88213
          serial: ABC123XYZ
          sold_at: '2026-07-15T14:32:00Z'
      properties:
        event_id:
          description: >-
            eventID of the EPCIS return event, retrievable from
            ``/events/{eventID}``.
          title: Event Id
          type: string
        gtin:
          description: Normalized GTIN-14 of the returned unit.
          title: Gtin
          type: string
        serial:
          description: GS1 AI(21) serial number of the returned unit.
          title: Serial
          type: string
        lot:
          anyOf:
            - type: string
            - type: 'null'
          description: GS1 AI(10) lot identifier recorded for this unit, when known.
          title: Lot
        returned_at:
          description: Event time of the recorded return.
          format: date-time
          title: Returned At
          type: string
        sold_at:
          anyOf:
            - format: date-time
              type: string
            - type: 'null'
          description: >-
            Event time of the sale this return reverses, when this organization
            recorded one.
          title: Sold At
        sale_transaction_reference:
          anyOf:
            - type: string
            - type: 'null'
          description: >-
            bizTransaction identifier carried on the sale event, scoped to this
            organization.
          title: Sale Transaction Reference
      required:
        - event_id
        - gtin
        - serial
        - returned_at
      title: CapturedReturnSchema
      type: object
    ErrorOut:
      description: |-
        RFC 9457 Problem Details response.

        All API errors are returned in this format with Content-Type:
        application/problem+json.
      examples:
        - detail: The requested resource was not found.
          error_code: not_found
          retryable: false
          status: 404
          timestamp: '2026-03-31T12:00:00+00:00'
          title: Not Found
          type: https://closient.com/docs/errors/not_found
        - detail: Validation error.
          details:
            - loc:
                - body
                - name
              msg: Field required
              type: missing
          error_code: validation_error
          retryable: false
          status: 422
          timestamp: '2026-03-31T12:00:00+00:00'
          title: Validation Error
          type: https://closient.com/docs/errors/validation_error
        - detail: Rate limit exceeded. Please try again later.
          error_code: rate_limited
          retry_after: 31
          retryable: true
          status: 429
          timestamp: '2026-03-31T12:00:00+00:00'
          title: Rate Limited
          type: https://closient.com/docs/errors/rate_limited
      properties:
        type:
          description: URI reference identifying the error type.
          title: Type
          type: string
        title:
          description: Short human-readable summary of the error.
          title: Title
          type: string
        status:
          description: HTTP status code.
          title: Status
          type: integer
        detail:
          description: Human-readable explanation of this specific occurrence.
          title: Detail
          type: string
        error_code:
          description: Machine-readable error code (e.g. not_found, unauthorized).
          title: Error Code
          type: string
        retryable:
          default: false
          description: Whether retrying the same request can succeed.
          title: Retryable
          type: boolean
        timestamp:
          description: ISO 8601 timestamp of when the error occurred.
          title: Timestamp
          type: string
        retry_after:
          anyOf:
            - type: integer
            - type: 'null'
          description: Seconds to wait before retrying (when applicable).
          title: Retry After
        owner_action_required:
          anyOf:
            - type: boolean
            - type: 'null'
          description: Whether the error requires account owner intervention.
          title: Owner Action Required
        details:
          description: Additional context (validation errors, etc.).
          title: Details
      required:
        - type
        - title
        - status
        - detail
        - error_code
        - timestamp
      title: ErrorOut
      type: object
  securitySchemes:
    APIKeyHeaderAuth:
      type: apiKey
      in: header
      name: X-API-Key
    OAuthTokenAuth:
      type: http
      scheme: bearer
    CookieGatedSessionAuth:
      type: apiKey
      in: cookie
      name: sessionid

````

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