eth_getBlockByNumber

eth_getBlockByNumber returns the full block object for an OP Mainnet block at a given height or named tag such as latest, safe, or finalized. It is the primary way to walk this OP Stack rollup — which produces a block roughly every 2 seconds and prices gas in ETH — for indexing and monitoring. Send the request to https://optimism.therpc.io/YOUR_API_KEY (chain ID 10, 0xa), choosing whether to include full transaction objects or just their hashes.

Use cases

• Walk OP Mainnet forward block-by-block in an indexer, incrementing the height by one each step.
• Fetch the latest block for a real-time dashboard tracking the sequencer's ~2s cadence.
• Read the finalized block to anchor queries that must survive a reorg before L1 settlement.
• Pull all transaction hashes from a block (with includeTransactions=false) before fetching receipts in bulk via eth_getBlockReceipts.

Parameters

Response

Example request

1curl https://optimism.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H "Content-Type: application/json" \
4  -d '{
5    "jsonrpc": "2.0",
6    "method": "eth_getBlockByNumber",
7    "params": [
8        "latest",
9        false
10      ],
11    "id": 1
12  }'

Try it live in the Optimism playground.

Errors & troubleshooting

Common pitfalls

• Pass a real boolean for includeTransactions, not the string "true" — JSON-RPC rejects the string form.
• When you need every receipt in an OP Mainnet block, call eth_getBlockReceipts once instead of issuing N separate eth_getTransactionReceipt requests.
• With includeTransactions=true, a heavily loaded OP Mainnet block can return a 1–2 MB response; size your buffers and timeouts accordingly.

Supported networks

• Mainnet — Chain ID: 10
• Sepolia — Chain ID: 11155420

See also

• eth_getBlockByHash
• eth_getBlockReceipts
• eth_blockNumber
• eth_getBlockTransactionCountByNumber

1curl https://optimism.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H 'Content-Type: application/json' \
4  -d '{"jsonrpc":"2.0","id":1,"method":"eth_getBlockByNumber","params":["latest",false]}'