Gupshup Opt-In API

openapi: 3.2.0
info:
  title: Gupshup WhatsApp Business Messaging Opt In API
  description: 'REST API for sending and managing WhatsApp Business messages through Gupshup. Messages are sent from a registered WhatsApp Business number that is bound to a Gupshup app; requests are authenticated with an `apikey` header tied to your Gupshup account. This document models the WhatsApp messaging surface on `https://api.gupshup.io/wa/api/v1` - sending session messages, sending pre-approved template (HSM) messages, managing user opt-in / opt-out, listing opted-in users, and listing an app''s templates.


    Scope and honesty note: the send-message (`POST /msg`) and send-template (`POST /template/msg`) operations are confirmed against Gupshup''s public API reference. The opt-in / opt-out, users, and template-list operations are documented in Gupshup''s WhatsApp API guide (historically under the `/sm` path, now migrating to the `/wa` path shown here); their request and response bodies are MODELED from the documentation rather than copied from a machine-readable source, and Gupshup uses `application/x-www-form-urlencoded` request bodies. Verify exact field names and response shapes against the live documentation before relying on this specification.'
  version: '1.0'
  contact:
    name: Gupshup
    url: https://www.gupshup.io
  x-modeled: true
servers:
- url: https://api.gupshup.io/wa/api/v1
  description: Gupshup WhatsApp Business API
security:
- apiKeyAuth: []
tags:
- name: Opt-In
  description: Manage user opt-in / opt-out and list interacted users.
paths:
  /app/opt/in/{appName}:
    parameters:
    - $ref: '#/components/parameters/AppName'
    post:
      operationId: markUserOptIn
      tags:
      - Opt-In
      summary: Mark a user opt-in
      description: Records that a user has consented to receive messages from the business, enabling template notifications to that number. Modeled from documentation. Legacy opt-in APIs are not supported for apps created after Aug 2025.
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/OptRequest'
      responses:
        '200':
          description: Opt-in recorded.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StatusResponse'
        '401':
          $ref: '#/components/responses/Unauthorized'
  /app/opt/out/{appName}:
    parameters:
    - $ref: '#/components/parameters/AppName'
    post:
      operationId: markUserOptOut
      tags:
      - Opt-In
      summary: Mark a user opt-out
      description: Records that a user has opted out of receiving messages from the business. Modeled from documentation.
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/OptRequest'
      responses:
        '200':
          description: Opt-out recorded.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StatusResponse'
        '401':
          $ref: '#/components/responses/Unauthorized'
  /users/{appName}:
    parameters:
    - $ref: '#/components/parameters/AppName'
    get:
      operationId: listUsers
      tags:
      - Opt-In
      summary: List interacted users and opt-in status
      description: Returns the users who have interacted with your business phone number and their opt-in status. Modeled from documentation.
      responses:
        '200':
          description: A list of users.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/UserListResponse'
        '401':
          $ref: '#/components/responses/Unauthorized'
components:
  schemas:
    UserListResponse:
      type: object
      properties:
        status:
          type: string
          example: success
        users:
          type: array
          items:
            $ref: '#/components/schemas/User'
    User:
      type: object
      properties:
        phoneCode:
          type: string
        phoneNumber:
          type: string
        optinStatus:
          type: string
          description: Whether the user is opted in.
        lastInteraction:
          type: string
          description: Timestamp of the user's last interaction.
    Error:
      type: object
      properties:
        status:
          type: string
          example: error
        message:
          type: string
    StatusResponse:
      type: object
      properties:
        status:
          type: string
          example: success
    OptRequest:
      type: object
      required:
      - user
      properties:
        user:
          type: string
          description: The user's phone number (with country code) to opt in or out.
  responses:
    Unauthorized:
      description: Missing or invalid apikey.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
  parameters:
    AppName:
      name: appName
      in: path
      required: true
      description: The Gupshup app name registered to the WhatsApp business number.
      schema:
        type: string
  securitySchemes:
    apiKeyAuth:
      type: apiKey
      in: header
      name: apikey
      description: Account API key sent in the `apikey` request header. Available from the Gupshup dashboard. Scopes requests to your account and its registered apps.