trace_block

trace_block returns OpenEthereum-style call-tree traces for every transaction in an OP Mainnet block, addressed by block number or a tag like latest. It flattens all internal calls, contract creations, and self-destructs across the whole block into one array, each entry tagged with its transactionPosition. On OP Mainnet — the OP Stack rollup where value and gas are denominated in ETH — this is the fastest way to capture every internal ETH movement in a block at once. Send the request to https://optimism.therpc.io/YOUR_API_KEY (chain ID 10, 0xa).

Use cases

• Extract all internal transactions in an OP Mainnet block for indexing or analytics — including ETH transfers that emit no events.
• Analyze MEV activity across every transaction in a specific block in a single call.
• Track ETH value flowing into and out of a contract (such as a Velodrome pool) for the entire block.

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": "trace_block",
7    "params": ["latest"],
8    "id": 1
9  }'

Try it live in the Optimism playground.

Errors & troubleshooting

Common pitfalls

• It returns every trace for every transaction, so a busy OP Mainnet block produces a very large response — page through historical blocks rather than fetching them in a tight loop.
• It needs a trace-enabled archive node; most public OP Mainnet endpoints do not expose the trace namespace.
• Avoid pending for production data — at ~2-second block times the pending block is unstable and its traces can change before the block is sealed and settled to L1.

Supported networks

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

See also

• trace_transaction
• trace_filter
• trace_replayBlockTransactions
• debug_traceBlockByNumber

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":"trace_block","params":["latest"]}'