The MCP forecommerce.
Plugged into the backend of 600+ brands
600+
Connected brands
100M+
US shoppers in our network
Millions
Live SKUs & offers
1
Endpoint to reach them all
The new layer for agentic commerce
One protocol sits between every agent and every store.
Models and apps shouldn’t integrate with 600 merchants one by one. They connect to Checkmate once — and inherit the entire network, with the data moat and merchant relationships already in place.
Agents & models
AI assistants, shopping copilots and autonomous agents that need to find, recommend and transact on real products.
OpenStock
A single Model Context Protocol server exposing catalogues, offers and code generation across the whole network.
600+ merchants
Top brands already plugged into Checkmate, ready to receive net-new, high-intent volume from day one.
The toolset
Everything an agent needs to shop the network.
A clean, typed set of tools — usable manually by a developer or autonomously by an agent. Same endpoint, same power.
list_brands()
Browse the network
Discover 600+ live merchants across beauty, apparel, wellness, home and more — all behind a single connection.
get_catalogue()
Pull live catalogues
Read structured product data, variants, imagery and inventory directly from the source, kept fresh in real time.
search_offers()
Surface live offers
Query active promotions and the best available pricing across the entire network in a single call.
generate_code()
Generate real codes
Mint working, merchant-backed discount codes on demand — the killer action no other commerce API can offer.
check_availability()
Confirm availability
Validate stock and eligibility before an agent recommends a product, so every suggestion can actually convert.
attribute_order()
Attribute & convert
Close the loop with clean attribution back to the merchant, turning agent intent into measurable net-new revenue.
Built for builders
Drop it in. Start selling.
OpenStock speaks the Model Context Protocol natively, so it works out of the box with any MCP-compatible client — Claude, ChatGPT, Cursor, your own agents and beyond. Point your client at our server and the tools appear instantly.
- Standard MCP transport — zero custom glue code
- Typed tools with predictable, structured responses
- Use it manually, or let an agent drive autonomously
- One credential for the entire 600+ brand network
{
"mcpServers": {
"openstock": {
"url": "https://mcp.joincheckmate.com",
"headers": {
"Authorization": "Bearer ${KEY}"
}
}
}
}Backed by Checkmate
The world’s most trusted shopping network.
OpenStock isn’t a cold API — it’s powered by Checkmate, a shopping platform millions of people already rely on to save money. Every agent you connect inherits that trust, that demand and those merchant relationships from day one.
5M+
Monthly active shoppers
Real people trusting Checkmate to find the best deal, every day.
1M+
Social media followers
One of the most-followed shopping communities on the internet.
600+
Brand partnerships
Direct relationships with the world’s most-loved merchants.
$500M+
Saved for shoppers
Half a billion dollars kept in our community’s pockets — and counting.
A rare win-win-win
Everyone in the loop comes out ahead.
For AI builders
- Ship real shopping superpowers in hours, not quarters
- No bespoke integrations with hundreds of merchants
- Generate working codes — a genuinely useful action
- Differentiate your product with native commerce
For shoppers
- Discover the right product across 600+ trusted brands
- Get real savings, surfaced automatically by their agent
- A faster, smarter path from intent to checkout
- One assistant that actually completes the purchase
For merchants
- Huge volumes of net-new, high-intent demand
- Distribution into every agent — with zero extra work
- Clean attribution back to each order
- A brand-new channel the competition can’t access
Built to plug into
The platforms defining the next era of commerce.
If your product helps people decide what to buy, Checkmate gives it the supply to actually deliver.
From zero to live
Three steps to the whole network.
Connect
Add the OpenStock MCP server to your client with a single config block and your access key.
Query
Your agent instantly discovers our tools — browse brands, read catalogues and search offers.
Convert
Generate real codes, hand shoppers off to checkout, and drive attributed revenue to merchants.
Connect your agentsto commerce.
We’re opening up developer access to a first cohort of partners. Request access and we’ll get you the docs and a key.
Merchant-backed codes · clean attribution · built on real supply