openapi: 3.0.3
info:
  title: Churnkey Billing Contacts API
  description: 'REST surface for Churnkey, retention and growth infrastructure for subscription companies. This document covers Churnkey''s server-to-server REST endpoints: the Data API (Cancel Flow sessions and aggregations, plus GDPR data-subject requests) under https://api.churnkey.co/v1/data, and the Event/Customer API (event tracking, customer updates, and billing-contact management for Failed Payment Recovery) under https://api.churnkey.co/v1/api. All requests are authenticated with an App ID header (x-ck-app) and an API key header. The Data API uses a Data API key (x-ck-api-key from Settings > Account); the event and billing-contact endpoints use a Churnkey API key. Churnkey''s personalized Cancel Flows are delivered client-side via a JavaScript SDK authorized with a server-computed HMAC-SHA256 authHash and are not modeled as REST paths here. Endpoint paths and parameters below reflect Churnkey''s public documentation as of the review date; request and response schemas are honestly modeled where the docs do not publish a full schema.'
  version: '1.0'
  contact:
    name: Churnkey
    url: https://churnkey.co
servers:
- url: https://api.churnkey.co/v1
  description: Churnkey production API
security:
- apiKeyAuth: []
  appIdAuth: []
tags:
- name: Billing Contacts
  description: Billing-contact management for Failed Payment Recovery.
paths:
  /api/events/customer-update/set-users:
    post:
      operationId: setBillingUsers
      tags:
      - Billing Contacts
      summary: Set billing contacts for a customer
      description: Attaches one or more users to a customer and flags which are billing admins. Billing admins receive Failed Payment Recovery (dunning) communications.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/SetUsersInput'
      responses:
        '200':
          description: The billing contacts were set.
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
        '401':
          $ref: '#/components/responses/Unauthorized'
  /api/events/customer-update/set-users/bulk:
    post:
      operationId: setBillingUsersBulk
      tags:
      - Billing Contacts
      summary: Set billing contacts for many customers
      description: Bulk variant of set-users - each array item uses the same structure as the single update.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: array
              items:
                $ref: '#/components/schemas/SetUsersInput'
      responses:
        '200':
          description: The billing contacts were set.
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
        '401':
          $ref: '#/components/responses/Unauthorized'
components:
  schemas:
    SetUsersInput:
      type: object
      required:
      - customerId
      - users
      properties:
        customerId:
          type: string
          description: Payment-provider customer ID (for example a Stripe customer ID).
        users:
          type: array
          items:
            $ref: '#/components/schemas/BillingUser'
    BillingUser:
      type: object
      required:
      - userId
      - data
      properties:
        userId:
          type: string
          description: Internal user identifier.
        data:
          type: object
          required:
          - email
          - name
          - billingAdmin
          properties:
            email:
              type: string
              format: email
            name:
              type: string
            phone:
              type: string
            billingAdmin:
              type: boolean
              description: When true, this user receives Payment Recovery emails.
          additionalProperties: true
    Error:
      type: object
      properties:
        error:
          type: object
          properties:
            code:
              type: string
            message:
              type: string
  responses:
    Unauthorized:
      description: Missing or invalid API key / App ID headers.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
  securitySchemes:
    apiKeyAuth:
      type: apiKey
      in: header
      name: x-ck-api-key
      description: Churnkey API key. The Data API (/v1/data) uses the Data API key from Settings > Account; the event and billing-contact endpoints (/v1/api) use a Churnkey API key.
    appIdAuth:
      type: apiKey
      in: header
      name: x-ck-app
      description: Churnkey Application ID (App ID) from Settings.