Checkmate Shoppers API

openapi: 3.1.0
info:
  version: 1.0.0
  title: OpenStock Health Shoppers API
  description: 'API provided by Checkmate to partners to provide access to merchant codes and shopper purchase history. All endpoints are POST with batched request/response shapes. Authenticate with `Authorization: Bearer <api_key>`. Ask partner representative for the API key.'
servers:
- url: https://api.openstock.sh
  description: Current environment
tags:
- name: Shoppers
paths:
  /v1/shoppers/history:
    post:
      tags:
      - Shoppers
      summary: Batch shopper purchase history
      description: Look up purchase history for one or more shoppers identified by SHA-256 hash of their normalised (lowercase-trimmed) email address. Never send raw email addresses. Up to 20 queries per request. Each result contains a flat `items` array of merchant interactions; unknown shoppers return an empty `items` array — there are no 404s.
      security:
      - BearerAuth: []
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/ShopperHistoryRequest'
      responses:
        '200':
          description: Per-query shopper history. Each result has a flat `items` array of merchant interactions. Unknown shoppers return an empty array.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ShopperHistoryResponse'
        '400':
          description: Invalid request body, malformed email_sha256, or query cap exceeded (max 20)
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '401':
          description: Missing or invalid API key
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '429':
          description: Too many requests. Rate limits are determined on a per partner basis.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
components:
  schemas:
    ShopperHistoryResult:
      type: object
      properties:
        query_id:
          type: string
          example: q1
        items:
          type: array
          items:
            $ref: '#/components/schemas/ShopperActivity'
          description: Flat list of merchant interactions for this shopper. Empty array when the shopper is unknown.
      required:
      - query_id
      - items
    ShopperHistoryRequest:
      type: object
      properties:
        queries:
          type: array
          items:
            $ref: '#/components/schemas/ShopperHistoryQuery'
          minItems: 1
          maxItems: 20
          description: Batch of shopper-history queries (1–20)
      required:
      - queries
    ShopperHistoryResponse:
      type: object
      properties:
        results:
          type: array
          items:
            $ref: '#/components/schemas/ShopperHistoryResult'
      required:
      - results
    ShopperHistoryQuery:
      type: object
      properties:
        query_id:
          type: string
          minLength: 1
          example: q1
          description: Caller-supplied opaque identifier correlated back in results
        email_sha256:
          type: string
          pattern: ^[0-9a-f]{64}$
          example: b94d27b9934d3e08a52e52d7da7dabfac484efe04294e576e50e46a7d3f5a4b8
          description: SHA-256 of the lowercase-trimmed email address; never send the raw email
      required:
      - query_id
      - email_sha256
    ErrorResponse:
      type: object
      properties:
        error:
          type: object
          properties:
            code:
              type: string
              example: VALIDATION_ERROR
            message:
              type: string
              example: Request body is invalid
          required:
          - code
          - message
      required:
      - error
    ShopperActivity:
      type: object
      properties:
        merchant_id:
          type: string
          example: 01hz4vdrcnxhfmfcvy3rfqk1fp
          description: Checkmate merchant ID
        merchant_name:
          type: string
          example: Acme Corp
        type:
          type: string
          enum:
          - visited
          - purchased
          example: purchased
          description: 'Activity type: "visited" or "purchased"'
      required:
      - merchant_id
      - merchant_name
      - type