Optimism (OP) API Documentation

Optimism

Optimism (OP) is an Ethereum Layer 2 optimistic rollup built on the OP Stack, with permissionless fault proofs activated on OP Mainnet on June 10, 2024. Solidity and other EVM languages compile to EVM bytecode, while execution clients maintain Ethereum-style account state and rollup nodes derive the canonical L2 chain from data published to Ethereum. Because the OP Stack preserves EVM execution and Ethereum data structures, standard Ethereum tooling and JSON-RPC conventions remain the application-facing baseline across OP Stack chains.

Optimism API Methods and Endpoints

NOWNodes exposes Optimism's interface, plus a few others, depending on what your integration needs: JSON-RPC for reading chain state and broadcasting transactions, WSS (WebSocket) for real-time subscriptions and events, Blockbook for indexed address, balance, transaction, and block lookups, and Trace/Debug for step-level execution analysis.

Browse the interfaces below for endpoint details, request parameters, response formats, and integration examples. Create an API key, select Mainnet or Testnet, choose the required interface, and start sending requests from your application.

Weighing Optimism RPC providers against each other? Read the comparison guide on our blog — this page stays focused on integration reference.