debug_getBadBlocks

debug_getBadBlocks asks an Arbitrum One node for every block it has seen and rejected as invalid since the process last started. Arbitrum One is an Optimistic Rollup (Nitro/ArbOS, chain ID 42161) that settles to Ethereum L1 and pays gas in ETH, so blocks arrive ordered by the sequencer rather than gossiped from many competing validators — under normal operation this list stays empty. Point your request at https://arbitrum.therpc.io/YOUR_API_KEY and you get back the blocks the node decoded but refused to accept, each paired with its raw RLP so you can inspect exactly why it failed validation.

Use cases

• Detect malformed or rule-violating blocks delivered to the node by a misbehaving peer or a desynced feed relay.
• Investigate a fork or sequencer hiccup by examining the alternative block the node rejected and comparing it to the canonical one on Arbiscan.
• Audit a Nitro client's validation logic by checking rejected blocks against ArbOS protocol rules during node upgrades.

Parameters

Este método no acepta parámetros. Pasa un array vacío [].

Response

Example request

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

Try it live in the Arbitrum One playground.

Errors & troubleshooting

Common pitfalls

• The bad-block list lives only in memory and resets every time the Nitro node restarts, so it reflects the current process, not the chain's full history.
• A healthy Arbitrum One node almost never accumulates bad blocks — an empty array is the normal, expected answer, not a sign of a failed request.
• Not every EVM client implements debug_getBadBlocks; a node that does not support it returns -32601 even though the debug namespace is otherwise enabled.

Supported networks

• Mainnet — Chain ID: 42161
• Sepolia — Chain ID: 421614

See also

• debug_traceBlock
• debug_traceBlockByHash
• debug_traceBlockByNumber

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