Blockchain API

Overview

A blockchain API is a software interface that lets applications query blockchain data, submit transactions, monitor events, or interact with network services without implementing the full protocol directly. The abstraction level determines how much responsibility remains with the application. Applications should handle network failures, rate limits, chain reorganizations, pagination, response-version changes, and inconsistent naming across chains. A successful HTTP response does not necessarily mean a transaction is finalized or even broadcast to enough peers. Blockchain APIs expose functions through JSON-RPC, REST, WebSocket, GraphQL, or protocol-specific interfaces. Common operations include retrieving balances, blocks, transactions, logs, fee estimates, and contract state, as well as broadcasting signed transactions.

An API can be provided by a self-hosted node, a managed infrastructure company, an explorer, or a payment provider. A payment API may abstract multiple blockchains further by creating invoices, monitoring addresses, normalizing statuses, and delivering webhooks rather than exposing raw node calls. Production integrations should plan for retries, idempotency, authentication, quotas, provider outages, and chain reorganizations. Critical services often use multiple endpoints or their own nodes for verification. Testing Blockchain API should cover malformed input, denied access, rate limits, timeouts, duplicates, asynchronous completion, and version changes. The Blockchain API contract should define identifiers, validation, authorization, status semantics, errors, limits, and version behavior at the same boundary. For Blockchain API, the application should preserve a correlation path from request construction through response, asynchronous completion, and final business state.

Version changes and provider-specific field semantics should be tested, especially when switching between networks that represent accounts and transactions differently.