Optimism is a low-cost and lightning-fast Ethereum L2 blockchain
Connect to OP Mainnet through reliable Optimism RPC endpoints from OnFinality. Use HTTPS or WebSocket to query blocks, balances, transactions and smart contracts, submit transactions, subscribe to live blockchain events, and access historical state through Archive-enabled infrastructure.
For advanced Optimism workloads, OnFinality also provides Trace and Debug APIs, RPC analytics, scalable rate limits, and dedicated node infrastructure for production applications.
Public endpoint rate limit: 5 req/sec
curl -H 'Content-Type: application/json' -d '{"id":1,"jsonrpc":"2.0","method":"eth_blockNumber"}' 'https://optimism.api.onfinality.io/public'https://optimism.api.onfinality.io/publicwss://optimism.api.onfinality.io/public-wsTrace OP Mainnet contract activity with OnFinality Optimism RPC. Combine archive reads, event logs and WebSocket subscriptions for Ethereum L2 app backends.
curl 'https://optimism.api.onfinality.io/public' \
-H 'Content-Type: application/json' \
--data '{"id":1,"jsonrpc":"2.0","method":"eth_blockNumber"}'Use the interface and request shown above for an initial check, then test the methods and traffic pattern your application actually needs.
Choose a shared RPC plan by response-unit allowance and peak throughput. Method weights and network-specific availability still apply.
Plan figures checked 8 November 2026. RU are not always raw requests; WebSocket responses also count toward limits. Check the current pricing and this network's method documentation. Node charges and applicable taxes are additional.
Connect to OP Mainnet over HTTPS for standard EVM JSON-RPC reads, transaction submission, contract calls, and historical data queries.
https://optimism.api.onfinality.io/publicUse the persistent WebSocket endpoint for subscriptions and event-driven applications that need live blockchain activity.
wss://optimism.api.onfinality.io/public-wsConnect to OP Mainnet through persistent WebSocket RPC for real-time blockchain applications. Subscribe to new blocks, logs, and onchain events without continuously polling an HTTP endpoint.
eth_subscribeeth_unsubscribeeth_newFiltereth_newBlockFiltereth_newPendingTransactionFiltereth_getFilterChangesThe Optimism Foundation public RPC does not support standard WebSocket connections. OnFinality provides both HTTPS and WebSocket access for applications that need real-time OP Mainnet data.
Query historical OP Mainnet state through OnFinality's Archive-enabled Optimism RPC infrastructure. Access historical blocks, balances, smart contract state, transactions, receipts, and event logs without operating your own archive node.
Use eth_getLogs to retrieve historical contract events for DeFi analytics, accounting, transaction analysis, indexers, explorers, and audit tools.
eth_getLogsInspect OP Mainnet transaction execution, debug failed contract calls, analyse internal transactions, and build advanced analytics using supported Trace and Debug APIs.
trace_blocktrace_calltrace_callManytrace_filtertrace_replayTransactiontrace_replayBlockTransactionsdebug_traceTransactiondebug_traceCalldebug_traceBlockByHashdebug_traceBlockByNumberTrace and Debug APIs are available on supported paid plans.
Use EVM-compatible JSON-RPC methods to read OP Mainnet state, query smart contracts, submit transactions, retrieve logs, subscribe to events, and inspect execution.
eth_blockNumbereth_chainIdeth_getBlockByHasheth_getBlockByNumbereth_getBlockReceiptseth_getBalanceeth_calleth_estimateGaseth_getCodeeth_getStorageAteth_sendRawTransactioneth_getTransactionByHasheth_getTransactionReceipteth_getTransactionCounteth_getLogseth_subscribeeth_getFilterChangestrace_blocktrace_calltrace_filterdebug_traceTransactiondebug_traceCallUse standard EVM RPC methods such as eth_estimateGas, eth_gasPrice, and eth_feeHistory for OP Mainnet transaction workflows. Applications that need total transaction cost estimates should also account for the OP Stack L1 data fee.
eth_estimateGaseth_gasPriceeth_feeHistoryQuery contract state, pools, balances, transactions and events while submitting transactions through EVM-compatible OP Mainnet RPC.
Query ETH and token balances, estimate transaction costs, submit signed transactions, retrieve receipts, and monitor deposits and withdrawals.
Use WebSocket subscriptions to monitor new blocks, contract logs and live OP Mainnet activity without continuous HTTP polling.
Combine Archive access, eth_getLogs, transactions and receipts to build historical datasets, dashboards and blockchain analytics.
Inspect transaction execution using Trace and Debug APIs for contract development, incident investigation and advanced analytics.
| OP Mainnet | OP Sepolia | |
|---|---|---|
| Chain ID | 10 | 11155420 |
| Currency | ETH | ETH |
| HTTPS | Supported | Supported |
| WebSocket | Supported | Supported |
| Environment | Production | Development / QA |
Move from shared Optimism RPC access to dedicated OP Mainnet nodes when your workload needs isolated resources, sustained throughput, intensive Archive or Trace queries, or greater operational control.
Plan access around the requests, operational requirements and release workflow your application needs.
Start with a connection check, then validate the reads, transactions or data workflows required by your application.
Review method-specific limits, plan allowances and usage before increasing traffic. Different methods can consume different response units.
Use your real client region and request pattern when evaluating latency, retries and service availability.
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