Go SDK for the Agentic Commerce Protocol

This repo bootstraps Go support for the Agentic Commerce Protocol (ACP). Both the checkout and delegated payment SDKs now live under a single Go module so you can depend on github.com/sumup/acp and call the handlers, models, and helpers you need.

Features

• Checkout API — plug your own business logic into NewCheckoutHandler by implementing CheckoutSessionService. The handler exposes the official ACP checkout contract over net/http, supports optional signature verification and timestamp skew enforcement, and emits typed responses generated from the OpenAPI spec.
• Delegated Payment API — payment service providers implement DelegatedPaymentProvider and wire it up via NewDelegatedPaymentHandler (optionally adding DelegatedPaymentWithAuthenticator and signature enforcement) to tokenize credentials and emit delegated vault tokens.
• Product Feed - helper for building and exporting a product feed.

Examples

Three runnable samples live under examples:

• examples/checkout implements CheckoutSessionService with an in-memory catalog and session store.
• examples/delegated_payment implements DelegatedPaymentProvider with an in-memory vault token map.
• examples/feed builds and exports a product feed in JSONL and CSV formats.

Checkout Sample

go run ./examples/checkout

Once the server is up, try exercising the flow with curl:

# Create a checkout session with two SKUs
curl -sS -X POST http://localhost:8080/checkout_sessions \
  -H 'Content-Type: application/json' \
  -d '{
        "items": [
          {"id": "latte", "quantity": 1},
          {"id": "mug", "quantity": 1}
        ],
        "buyer": {
          "first_name": "Ava",
          "last_name": "Agent",
          "email": "ava.agent@example.com"
        }
      }'

# Complete the session once you have the id from the response above
curl -sS -X POST http://localhost:8080/checkout_sessions/<session_id>/complete \
  -H 'Content-Type: application/json' \
  -d '{
        "payment_data": {
          "provider": "stripe",
          "token": "pm_sample_token"
        }
      }'

Feel free to copy this sample into your own project and swap the in-memory store for your real product catalog, fulfillment rules, and payment hooks.

To see webhook delivery end-to-end, export the environment variables below before starting the sample server. The handler will POST an `order_created` event every time a checkout session completes.

```bash
export ACP_WEBHOOK_ENDPOINT="https://webhook.site/your-endpoint"
export ACP_WEBHOOK_HEADER="Merchant_Name-Signature"
export ACP_WEBHOOK_SECRET="super-secret"
go run ./examples/checkout

Delegated Payment Sample

go run ./examples/delegated_payment

Then call it with:

curl -sS -X POST http://localhost:8080/agentic_commerce/delegate_payment \
  -H 'Content-Type: application/json' \
  -d '{
        "payment_method": {
          "type": "card",
          "card_number_type": "fpan",
          "number": "4242424242424242",
          "exp_month": "11",
          "exp_year": "2026",
          "display_last4": "4242",
          "display_card_funding_type": "credit",
          "metadata": {"issuer": "demo-bank"}
        },
        "allowance": {
          "reason": "one_time",
          "max_amount": 2000,
          "currency": "usd",
          "checkout_session_id": "cs_000001",
          "merchant_id": "demo-merchant",
          "expires_at": "2025-12-31T23:59:59Z"
        },
        "risk_signals": [
          {"type": "card_testing", "action": "manual_review", "score": 10}
        ],
        "metadata": {"source": "sample"}
      }'

Product Feed Sample

go run ./examples/feed

This writes compressed feed exports to examples/feed/output/product_feed.jsonl.gz and examples/feed/output/product_feed.csv.gz.

License

Apache 2.0