debug_traceBlock

debug_traceBlock takes a Base block supplied directly as RLP-encoded bytes, re-executes it against the parent state, and returns opcode-level execution traces for every transaction inside. Unlike the by-hash and by-number variants, you hand the node the raw block rather than a reference to one already in its database. Base is Coinbase's OP Stack optimistic rollup that pays gas in ETH and settles to Ethereum L1, so its execution client accepts the same RLP block encoding as Geth. Post the request to https://base.therpc.io/YOUR_API_KEY (chain ID 8453, hex 0x2105) with the 0x-prefixed RLP block and an optional tracer config, and the node returns one trace per transaction in block order.

Use cases

• Trace a custom or modified Base block that is not yet on-chain — for example one assembled in a local OP Stack simulation environment to test how a set of transactions would execute against the parent state.
• Reproduce a Base block's execution when you already hold its RLP bytes (for instance from a p2p capture or a block export) without first importing it into the node's canonical chain.

Parameters

Response

Example request

1curl https://base.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H "Content-Type: application/json" \
4  -d '{
5    "jsonrpc": "2.0",
6    "method": "debug_traceBlock",
7    "params": [
8        "0xf9...",
9        {}
10      ],
11    "id": 1
12  }'

Try it live in the Base playground.

Errors & troubleshooting

Common pitfalls

• Producing a correctly RLP-encoded Base block is fiddly; most callers fetch the block via eth_getBlockByHash with full transactions and re-encode it, since a malformed RLP payload fails to decode.
• The parent state of any historical Base block must be present, so an archive node is required to replay anything but very recent blocks.
• Performance matches debug_traceBlockByHash — it is a full block replay, so a dense Base block of DEX and consumer-app transactions is heavy and may approach the trace timeout.

Supported networks

• Mainnet — Chain ID: 8453
• Sepolia — Chain ID: 84532

See also

• debug_traceBlockByNumber
• debug_traceBlockByHash
• debug_traceTransaction

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