Checkmate

aid: checkmate
name: Checkmate
description: 'Checkmate is a shopping intelligence and data company whose network powers three products: Checkmate for consumers
  (a browser extension and mobile app that automatically finds the best price and applies working discount codes across 284,000+
  merchants for 5M+ monthly shoppers), Mate for brands (AI-powered revenue intelligence), and OpenStock for publishers and
  agents. OpenStock is a commerce API and Model Context Protocol (MCP) server that exposes the entire Checkmate network through
  a single endpoint — letting AI agents, shopping copilots, and applications discover merchants, pull live catalogues and
  offers, generate real merchant-backed discount codes, check availability, and attribute orders. Backed by GV (Google Ventures).'
url: https://raw.githubusercontent.com/api-evangelist/checkmate/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- gv
x-tier: enriched
x-tier-reason: portfolio-lead
specificationVersion: '0.20'
created: '2026-07-17'
modified: '2026-07-18'
tags:
- Company
- Consumer
- Commerce
- Ecommerce
- Shopping
- Discount Codes
- Coupons
- Merchants
- MCP
- Agentic Commerce
- Retail
- API
apis:
- name: OpenStock API
  description: OpenStock is the commerce API Checkmate provides to partners and agents for access to merchant discovery, merchant
    discount/offer codes, and shopper purchase history across the Checkmate network of 284,000+ merchants. All endpoints are
    POST with batched request/response shapes; authenticate with an Authorization Bearer API key issued by a partner representative.
    The same network is also exposed as a Model Context Protocol (MCP) server.
  humanURL: https://openstock.sh
  baseURL: https://api.openstock.sh
  tags:
  - Commerce
  - Ecommerce
  - Merchants
  - Discount Codes
  - Offers
  - MCP
  properties:
  - type: OpenAPI
    url: openapi/checkmate-openstock-openapi-original.json
  - type: Overlay
    url: overlays/checkmate-openstock-overlay.yaml
  - type: Documentation
    url: https://api.openstock.sh/docs
  - type: APIReference
    url: https://api.openstock.sh/docs
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Website
  url: https://joincheckmate.com
- type: DeveloperPortal
  url: https://openstock.sh
- type: Documentation
  url: https://api.openstock.sh/docs
- type: APIReference
  url: https://api.openstock.sh/docs
- type: Blog
  url: https://joincheckmate.com/blog
- type: Support
  url: mailto:support@joincheckmate.com
- type: SignUp
  url: https://joincheckmate.com/login
- type: PrivacyPolicy
  url: https://joincheckmate.com/privacy-policy
- type: TermsOfService
  url: https://joincheckmate.com/terms-conditions
- type: Security
  url: https://joincheckmate.com/security
- type: VulnerabilityDisclosure
  url: security/checkmate-vulnerability-disclosure.yml
- type: SecurityTxt
  url: well-known/checkmate-security.txt
- type: WellKnown
  url: well-known/checkmate-well-known.yml
- type: DomainSecurity
  url: security/checkmate-domain-security.yml
- type: LLMsTxt
  url: llms/checkmate-llms.txt
- type: MCPServer
  url: mcp/checkmate-mcp.yml
- type: Authentication
  url: authentication/checkmate-authentication.yml
- type: ErrorCatalog
  url: errors/checkmate-problem-types.yml
- type: Conventions
  url: conventions/checkmate-conventions.yml
- type: Idempotency
  url: conventions/checkmate-conventions.yml
- type: Conformance
  url: conformance/checkmate-conformance.yml
- type: Lifecycle
  url: lifecycle/checkmate-lifecycle.yml
- type: DataModel
  url: data-model/checkmate-data-model.yml
- type: AgentSkill
  url: skills/_index.yml
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence