Crypto Payment API Integration Guide

Integrating a crypto payment API requires a slightly different architectural approach than traditional fiat APIs due to the asynchronous nature of blockchain confirmations.

1. Invoice Generation

The flow begins by requesting an invoice. You send a POST request containing the fiat amount (e.g., $50) and your order ID. The API returns a unique blockchain address, the exact crypto amount calculated in real-time, and a countdown timer locking in the exchange rate.

2. The Waiting Game (Webhooks)

Unlike credit cards where the authorization is instantaneous, crypto payments require the user to broadcast a transaction from their wallet, which must then be mined into a block.

Therefore, your application should not poll the API continuously. Instead, rely on Cryptographically Signed Webhooks. The API will push a notification to your server the moment a transaction is detected in the mempool (0-conf) and again when it is fully confirmed.

3. State Management

Your database should track the invoice states: NEW, PENDING, COMPLETED, PARTIAL_PAYMENT, and EXPIRED. Properly handling edge cases, such as a user sending slightly less crypto than requested, is the hallmark of a robust integration.