Coinbase Commerce

Coinbase Commerce provides cryptocurrency payment processing — accept Bitcoin, Ethereum, USDC, and other cryptocurrencies via API. For agents operating in the crypto/web3 space or needing censorship-resistant payment rails, this is the primary API. The model is simple: create a charge with an amount, get a payment page or address, receive webhook notification when payment is confirmed on-chain. The service handles wallet generation, blockchain monitoring, and payment confirmation.

Authentication uses API keys via header. The model is simple — one key per account. Webhook signature verification uses shared secrets. The auth model is minimal but appropriate for the service scope. There are no complex permission hierarchies. Rate limits are documented. The main security consideration is webhook verification — agents must validate signatures to prevent spoofed payment notifications.

Documentation is adequate but not extensive. The API reference covers all endpoints. The webhook event types are documented. Getting started is straightforward. The main gap is limited guidance on handling edge cases (partial payments, network congestion, fork scenarios). For agents new to crypto payments, more conceptual documentation would help. The docs assume familiarity with blockchain payment concepts.

The API is REST-based with a small surface: charges (create, list, get) and checkouts (create, list, get). A charge represents a one-time payment request. A checkout represents a reusable payment page. The webhook system delivers events for pending, confirmed, failed, and expired payments. The API design is appropriately simple for the payment flow. The main limitation is the unidirectional model — this is for accepting payments, not for sending them or managing wallets.

Error handling follows REST conventions. The main operational complexity is blockchain confirmation times: Bitcoin transactions can take minutes to hours for full confirmation, while stablecoin transactions on fast chains confirm in seconds. Agents must handle the asynchronous nature of crypto payments, including partial payments, overpayments, and expired charges. The webhook system handles most of this but agents need to implement the state machine correctly.