openapi: 3.0.3
info:
  title: Blend Public Borrowers & Parties Closings & eSignature API
  description: 'The Blend Public API is the documented REST surface of the Blend Labs digital lending and account-opening platform (developers.blend.com). It lets lenders and certified technology partners programmatically create and manage lending applications across home lending (mortgage), consumer lending, and deposit account opening; manage borrowers/parties, documents and disclosures, pricing, closings and eSignature packages, follow-ups (tasks), lenders and assignments; subscribe to webhook event notifications; and export industry-standard loan files (Fannie Mae 3.2, MISMO 3.3.1/3.4) into a loan origination system (LOS).


    endpointsModeled: The paths, methods, and resource names in this document are modeled from Blend''s public developer documentation and reference at developers.blend.com (llms.txt endpoint index, Quick Start Guide, LOS Guide, and the create/export home-loan guides). Blend does not publish a fully open self-service OpenAPI - the reference is credential-gated and access tokens are issued to Blend customers and certified partners. Request/response schemas below are representative rather than field-complete; obtain the authoritative machine spec at https://developers.blend.com/blend/openapi once you hold API credentials.'
  version: 12.0.0
  contact:
    name: Blend Labs
    url: https://developers.blend.com/blend
  termsOfService: https://blend.com/legal/terms-of-service/
servers:
- url: https://api.blendlabs.com
  description: Production
- url: https://api.beta.blendlabs.com
  description: Beta / integration environment (used in Blend's documentation examples)
security:
- bearerAuth: []
tags:
- name: Closings & eSignature
  description: Closings, packages, eNotes, and RON sessions.
paths:
  /closings:
    post:
      operationId: createClosing
      tags:
      - Closings & eSignature
      summary: Create a closing
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
      responses:
        '201':
          description: The created closing.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Closing'
    get:
      operationId: listClosings
      tags:
      - Closings & eSignature
      summary: List closings
      responses:
        '200':
          description: A list of closings.
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      $ref: '#/components/schemas/Closing'
  /closings/{closingId}:
    parameters:
    - $ref: '#/components/parameters/ClosingId'
    get:
      operationId: getClosing
      tags:
      - Closings & eSignature
      summary: Get a closing
      responses:
        '200':
          description: The closing.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Closing'
    patch:
      operationId: updateClosing
      tags:
      - Closings & eSignature
      summary: Update a closing
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
      responses:
        '200':
          description: The updated closing.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Closing'
  /closings/{closingId}/send:
    parameters:
    - $ref: '#/components/parameters/ClosingId'
    post:
      operationId: submitClosing
      tags:
      - Closings & eSignature
      summary: Submit (send) a closing
      responses:
        '202':
          description: Closing submitted for processing.
  /applications/{id}/packages:
    parameters:
    - $ref: '#/components/parameters/ApplicationId'
    get:
      operationId: listPackages
      tags:
      - Closings & eSignature
      summary: List eSignature packages
      responses:
        '200':
          description: The packages for the application.
    post:
      operationId: createPackage
      tags:
      - Closings & eSignature
      summary: Create an eSignature package
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
      responses:
        '201':
          description: The created package.
  /applications/{id}/packages/{packageId}/issue:
    parameters:
    - $ref: '#/components/parameters/ApplicationId'
    - name: packageId
      in: path
      required: true
      schema:
        type: string
    post:
      operationId: issuePackage
      tags:
      - Closings & eSignature
      summary: Issue a draft package for signature
      responses:
        '202':
          description: Package issued to recipients.
components:
  parameters:
    ApplicationId:
      name: id
      in: path
      required: true
      schema:
        type: string
      description: The application ID.
    ClosingId:
      name: closingId
      in: path
      required: true
      schema:
        type: string
      description: The closing ID.
  schemas:
    Closing:
      type: object
      properties:
        id:
          type: string
        applicationId:
          type: string
        status:
          type: string
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT
      description: Blend authenticates requests with an authorization Bearer token. Each call must also send blend-api-version (to pin the API version) and blend-target-instance (tenant~instance) headers. API Secret Keys are exchanged for short-lived, request-scoped JWTs at Blend's API Gateway. Credentials are issued to Blend customers and certified partners - contact your Blend account team or partnerships to obtain them.