StateSet API Docs

Agentic Commerce Protocol (ACP) Handler is a Rust server that implements OpenAI’s Agentic Commerce Protocol. It provides checkout session APIs, delegated payments, and optional gRPC access so you can keep orders and compliance in your own stack while enabling ChatGPT Instant Checkout experiences.

Key capabilities

Full checkout session lifecycle for the ACP spec
Delegated payment endpoint with vault token support
Optional Stripe PaymentIntent integration
Idempotency keys and request tracing
Swagger UI at /docs and OpenAPI JSON at /openapi.json
gRPC API mirroring the HTTP endpoints

Architecture overview

Quickstart

cargo build --release
cargo run --release

The HTTP server listens on http://0.0.0.0:8080 by default. The gRPC server listens on 0.0.0.0:50051. To run the demo flow:

./demo_test.sh

Create a checkout session

curl -X POST https://yourapp.com:8080/checkout_sessions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer api_key_123" \
  -H "API-Version: 2025-09-29" \
  -d '{
    "items": [{ "id": "item_123", "quantity": 2 }],
    "buyer": { "email": "buyer@example.com" }
  }'

Core endpoints

Method	Endpoint	Description
POST	`/checkout_sessions`	Create a checkout session
GET	`/checkout_sessions/:id`	Retrieve a checkout session
POST	`/checkout_sessions/:id`	Update a checkout session
POST	`/checkout_sessions/:id/complete`	Complete checkout and create order
POST	`/checkout_sessions/:id/cancel`	Cancel a checkout session
POST	`/agentic_commerce/delegate_payment`	Delegated payment (vault token)
GET	`/health`	Health check
GET	`/ready`	Readiness check
GET	`/docs`	Swagger UI
GET	`/openapi.json`	OpenAPI spec

The handler holds delegated payment tokens. Terminate TLS in front of it, never log the request body, and keep the Stripe keys in the environment rather than the config file the Compose assets ship with — a token scoped to a session is still a token that can complete a purchase.

Delegated payments

The delegated payment endpoint accepts payment tokens from a PSP vault. Tokens are validated for allowance and expiry and are consumed after use.

Stripe integration

Set the following environment variables before starting the server to process delegated payments with Stripe:

STRIPE_SECRET_KEY
STRIPE_PUBLISHABLE_KEY (optional)
STRIPE_WEBHOOK_SECRET (optional, for webhook signature verification)

gRPC access

The gRPC API mirrors the HTTP endpoints and uses the same API keys. Send authorization: Bearer <api_key> as gRPC metadata. The repository also includes:

A Next.js dashboard for monitoring checkout sessions
A ChatGPT widget server for MCP-based agent flows
Kubernetes and Docker Compose deployment assets

Next steps

Agentic Commerce Protocol

The protocol this handler implements.

ACP endpoints

The surface it exposes.

Deploy an ACP handler

Getting it running on managed Kubernetes.

UCP handler

The sibling protocol handler.

Last modified on August 29, 2026

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Agentic Commerce Protocol Handler

Key capabilities

Architecture overview

Quickstart

Create a checkout session

Core endpoints

Delegated payments

Stripe integration

gRPC access

Next steps

Agentic Commerce Protocol

ACP endpoints

Deploy an ACP handler

UCP handler

​Key capabilities

​Architecture overview

​Quickstart

​Create a checkout session

​Core endpoints

​Delegated payments

​Stripe integration

​gRPC access

​Related components

​Next steps

Agentic Commerce Protocol

ACP endpoints

Deploy an ACP handler

UCP handler

Key capabilities

Architecture overview

Quickstart

Create a checkout session

Core endpoints

Delegated payments

Stripe integration

gRPC access

Related components

Next steps