debug_traceBlockByHash

debug_traceBlockByHash re-executes every transaction in an OP Mainnet block — looked up by its block hash — and returns an opcode-level execution trace for each one. OP Mainnet is an OP Stack rollup with roughly 2-second blocks and ETH as the gas token, so a single block can pack many transactions; this method replays them all against the parent state in canonical order. Send the call to https://optimism.therpc.io/YOUR_API_KEY (chain ID 10, 0xa) with the 32-byte block hash and an optional tracer config, and you get one trace result per transaction.

Use cases

• Deterministically trace a specific OP Mainnet block when you only hold its hash — for example from a reorg or sequencer-investigation log.
• Audit every internal call within a known side-chain or replaced block to see what execution it would have produced.
• Build a block-level call graph for MEV analysis on OP Mainnet using callTracer, capturing all nested calls in one request.

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": "debug_traceBlockByHash",
7    "params": [
8        "0x0000000000000000000000000000000000000000000000000000000000000000",
9        {}
10      ],
11    "id": 1
12  }'

Try it live in the Optimism playground.

Errors & troubleshooting

Common pitfalls

• Costs the same as debug_traceBlockByNumber — it replays every transaction in the block, so the hash variant is no cheaper.
• Tracing any non-recent OP Mainnet block needs an archive node; pruned nodes lack the historical state to replay it.
• A block dense with complex DeFi calls can exceed the default trace timeout on remote nodes; use a compact tracer like callTracer to keep responses manageable.

Supported networks

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

See also

• debug_traceBlockByNumber
• debug_traceBlock
• debug_traceTransaction
• trace_block

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":"debug_traceBlockByHash","params":["0x0000000000000000000000000000000000000000000000000000000000000000",{}]}'