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OP Sepolia (Optimism Sepolia) RPC Endpoint

Connect to OP Sepolia 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 validate applications before production.

For advanced Optimism Sepolia workloads, OnFinality also provides Trace and Debug APIs, RPC analytics, scalable rate limits, and dedicated node infrastructure for development and QA.

Chain ID11155420

CurrencyETH

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Public endpoint rate limit: 5 req/sec

Connect to OP Sepolia RPC

Mainnet Sepolia

curl -H 'Content-Type: application/json' -d '{"id":1,"jsonrpc":"2.0","method":"eth_blockNumber"}' 'https://optimism-sepolia.api.onfinality.io/public'

curl -H 'Content-Type: application/json' -d '{"id":1,"jsonrpc":"2.0","method":"eth_blockNumber"}' 'https://optimism-sepolia.api.onfinality.io/public'

HTTPs

https://optimism-sepolia.api.onfinality.io/public

https://optimism-sepolia.api.onfinality.io/public

Websocket

wss://optimism-sepolia.api.onfinality.io/public-ws

wss://optimism-sepolia.api.onfinality.io/public-ws

Go to Growth Plan

High Performance
Powerful RPC Analytics
Up to 500 rps
No daily response limit
Priority Support
Decentralized Servers

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OP Sepolia RPC details

Item

Value

Network

OP Sepolia

Also Known As

Optimism Sepolia

Chain ID

11155420

Currency

ETH

Protocol

EVM JSON-RPC

HTTPS

Supported

WebSocket

Supported

Archive Access

Supported

Trace / Debug

Supported on Paid Plans

Public Rate Limit

5 req/sec

Free Plan

Up to 40 req/sec

30-day Uptime

99.99% · Check details

Regions

Hong Kong / France / N. Virginia

Optimism HTTPS RPC

Connect to OP Sepolia over HTTPS for standard EVM JSON-RPC reads, transaction submission, contract calls, and historical data queries.

https://optimism-sepolia.api.onfinality.io/public

Optimism WebSocket RPC

Use the persistent WebSocket endpoint for subscriptions and event-driven applications that need live blockchain activity.

wss://optimism-sepolia.api.onfinality.io/public-ws

Real-Time Optimism WebSocket RPC

Connect 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_subscribe
eth_unsubscribe
eth_newFilter
eth_newBlockFilter
eth_newPendingTransactionFilter
eth_getFilterChanges

The 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.

Optimism Archive RPC

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.

Historical Logs

Use eth_getLogs to retrieve historical contract events for DeFi analytics, accounting, transaction analysis, indexers, explorers, and audit tools.

eth_getLogs

Optimism Trace and Debug APIs

Inspect OP Mainnet transaction execution, debug failed contract calls, analyse internal transactions, and build advanced analytics using supported Trace and Debug APIs.

Trace APIs

trace_block
trace_call
trace_callMany
trace_filter
trace_replayTransaction
trace_replayBlockTransactions

Debug APIs

debug_traceTransaction
debug_traceCall
debug_traceBlockByHash
debug_traceBlockByNumber

Trace and Debug APIs are available on supported paid plans.

Supported Optimism RPC Methods

Use EVM-compatible JSON-RPC methods to read OP Mainnet state, query smart contracts, submit transactions, retrieve logs, subscribe to events, and inspect execution.

Blocks and Chain State

eth_blockNumber
eth_chainId
eth_getBlockByHash
eth_getBlockByNumber
eth_getBlockReceipts

Accounts and Smart Contracts

eth_getBalance
eth_call
eth_estimateGas
eth_getCode
eth_getStorageAt

Transactions

eth_sendRawTransaction
eth_getTransactionByHash
eth_getTransactionReceipt
eth_getTransactionCount

Logs and Real-Time Events

eth_getLogs
eth_subscribe
eth_getFilterChanges

Trace and Debug

trace_block
trace_call
trace_filter
debug_traceTransaction
debug_traceCall

View all supported Optimism RPC methods →

Query OP Sepolia Gas and Transaction Costs

Use standard EVM RPC methods such as eth_estimateGas, eth_gasPrice, and eth_feeHistory for OP Sepolia transaction workflows. Applications that need total transaction cost estimates should also account for the OP Stack L1 data fee.

eth_estimateGas
eth_gasPrice
eth_feeHistory

Build on OP Sepolia with OnFinality

DeFi Applications

Query contract state, pools, balances, transactions and events while submitting transactions through EVM-compatible OP Sepolia RPC.

Wallets and Exchanges

Query ETH and token balances, estimate transaction costs, submit signed transactions, retrieve receipts, and monitor deposits and withdrawals.

Real-Time Applications

Use WebSocket subscriptions to monitor new blocks, contract logs and live OP Mainnet activity without continuous HTTP polling.

Indexers and Analytics

Combine Archive access, eth_getLogs, transactions and receipts to build historical datasets, dashboards and blockchain analytics.

Smart Contract Debugging

Inspect transaction execution using Trace and Debug APIs for contract development, incident investigation and advanced analytics.

OP Mainnet and OP Sepolia RPC

	OP Mainnet	OP Sepolia
Chain ID	10	11155420
Currency	ETH	ETH
HTTPS	Supported	Supported
WebSocket	Supported	Supported
Environment	Production	Development / QA

Explore OP Sepolia RPC →

Dedicated Optimism Nodes

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.