{"slug": "testing-an-ai-shopping-agent-s-checkout-flow-there-s-no-sandbox-for-that-yet-so", "title": "Testing an AI shopping agent's checkout flow? There's no sandbox for that yet — so I built one", "summary": "A developer built acp-sandbox, a hosted mock merchant implementing the Agentic Commerce Protocol (ACP) checkout API, to fill the gap in testing AI shopping agents. The sandbox supports the full checkout session lifecycle, logs requests per API key, and pairs with agent-identity-mcp for disposable buyer identities.", "body_md": "If you're building or evaluating an AI agent that can shop and check out on its own, you've probably run into the new \"agentic commerce\" protocols: [ACP](https://github.com/agentic-commerce-protocol/agentic-commerce-protocol) (OpenAI + Stripe + Meta), AP2 (Google), and UCP. They define how an agent talks to a merchant to create a checkout session, apply a payment token, and get an order back.\n\nStripe's own test mode covers the *payment* half fine — test cards, test API keys. But there's no hosted \"fake merchant\" you can point your agent at to verify the *protocol* half: does your agent correctly create a session, handle a 422 idempotency conflict, parse the order response, retry politely? You either mock it yourself from the spec, or risk finding out against a real merchant.\n\nSo I built ** acp-sandbox** — a small hosted mock merchant implementing the ACP checkout API, live at\n\nIt implements the real `checkout_sessions`\n\nlifecycle from ACP's [2026-04-17 spec](https://github.com/agentic-commerce-protocol/agentic-commerce-protocol/tree/main/spec/2026-04-17): create, retrieve, update, complete, cancel. Responses match the actual `CheckoutSession`\n\n/`Order`\n\n/`Error`\n\nschemas for the fields it supports — I pulled the OpenAPI spec directly rather than guessing field names.\n\n```\n# get a test key, no signup\ncurl -X POST https://acp-sandbox.flo-voice1.com/keys \\\n  -H \"Content-Type: application/json\" -d '{\"email\":\"you@example.com\"}'\n\n# create a session against the demo catalog\ncurl -X POST https://acp-sandbox.flo-voice1.com/checkout_sessions \\\n  -H \"Authorization: Bearer acps_test_...\" \\\n  -H \"Content-Type: application/json\" \\\n  -d '{\"line_items\":[{\"id\":\"item_demo_headphones\",\"quantity\":1}],\"currency\":\"usd\"}'\n```\n\nEvery request/response is logged per API key (`GET /logs`\n\n), so you can see exactly what your agent sent when something doesn't work.\n\n`complete`\n\nalways succeeds once you send `payment_data`\n\n.`delegate_authentication`\n\nflow.`ready_for_payment`\n\n.ACP is still beta (5 spec revisions in about 7 months), so this will need upkeep as the protocol moves. Scoped tightly on purpose rather than trying to cover AP2/UCP too — happy to extend it if there's real interest.\n\nIf you're also building [agent-identity-mcp](https://github.com/flovoice53-tech/agent-identity-mcp) or similar (disposable email/phone for AI agents to use as a buyer identity), it pairs directly with this — identity on one side, a merchant to check out with on the other.\n\nRepo: [https://github.com/flovoice53-tech/acp-sandbox](https://github.com/flovoice53-tech/acp-sandbox)\n\nLive: [https://acp-sandbox.flo-voice1.com](https://acp-sandbox.flo-voice1.com)", "url": "https://wpnews.pro/news/testing-an-ai-shopping-agent-s-checkout-flow-there-s-no-sandbox-for-that-yet-so", "canonical_source": "https://dev.to/flovoice53tech/testing-an-ai-shopping-agents-checkout-flow-theres-no-sandbox-for-that-yet-so-i-built-one-dgo", "published_at": "2026-08-26 06:46:59+00:00", "updated_at": "2026-08-26 07:13:43.429334+00:00", "lang": "en", "topics": ["ai-agents", "ai-products", "developer-tools"], "entities": ["acp-sandbox", "Agentic Commerce Protocol", "OpenAI", "Stripe", "Meta", "Google", "agent-identity-mcp"], "alternates": {"html": "https://wpnews.pro/news/testing-an-ai-shopping-agent-s-checkout-flow-there-s-no-sandbox-for-that-yet-so", "markdown": "https://wpnews.pro/news/testing-an-ai-shopping-agent-s-checkout-flow-there-s-no-sandbox-for-that-yet-so.md", "text": "https://wpnews.pro/news/testing-an-ai-shopping-agent-s-checkout-flow-there-s-no-sandbox-for-that-yet-so.txt", "jsonld": "https://wpnews.pro/news/testing-an-ai-shopping-agent-s-checkout-flow-there-s-no-sandbox-for-that-yet-so.jsonld"}}