0n3
MCP servers · UCP — Universal Commerce Protocol · connector · GPT action

Connect ChatGPT to UCP — Universal Commerce Protocol

One line gives ChatGPT your UCP — Universal Commerce Protocol account as tools: 3 endpoints, list offers, create checkout, get download link, called with your own connection. No key in the prompt, a receipt for every call, revoke ChatGPT's access alone any time.

Get the line for ChatGPTConnect UCP — Universal Commerce Protocol first

Three steps

  1. Create a free 0n3 account and connect UCP — Universal Commerce Protocol. Paste a key or sign in; it lands in your vault, encrypted.
  2. Install 0n3 into ChatGPT. A custom connector in Developer mode, or an Action on a custom GPT from the OpenAPI spec.
  3. Ask ChatGPT: whoami. Then: "List offers in UCP — Universal Commerce Protocol".
Custom connector (needs Developer mode)
  1. Settings → Connectors (or Apps) → Advanced → Developer mode on
  2. Create → name 0n3 · MCP server URL https://0n3.app/mcp · Authentication: OAuth
  3. Finish the sign-in with your 0n account
  4. Enable the connector in a chat and ask: "whoami"

ChatGPT connectors cannot send a static header, so 0n3 signs you in through its OAuth door (dynamic client registration is on).

The line above carries a placeholder; 0n3.app/install mints a real key named for ChatGPT and fills it in.

What ChatGPT can then do in UCP — Universal Commerce Protocol

List offers · List all active products, downloads, and plans1
List offersGET /api/commerce/offers
Create checkout · Generate a Stripe Checkout session for a product slug1
Create a checkoutPOST /api/commerce/checkout
Get download link · Verify entitlement and return a signed download URL1
Get a download linkGET /api/commerce/download
List purchases · List the user's completed purchases0
List the user's completed purchases

UCP — Universal Commerce Protocol in other AI clients

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ChatGPT with other apps

Hostinger363 endpointsTelegram132 endpointsPipedrive95 endpointsResend67 endpointsSquare57 endpointsLinkedIn50 endpointsSlack45 endpointsFigma32 endpointsCloudConvert32 endpointseBay25 endpointsQuickBooks21 endpointsCloudflare21 endpoints