debug_storageRangeAt

debug_storageRangeAt reads the raw storage trie of a contract deployed on Base, the Coinbase-built OP Stack rollup that settles to Ethereum L1 and meters gas in ETH. Given a block hash, a transaction index within that block, and a contract address, the node reconstructs the EVM state immediately after that transaction executed and returns a paginated slice of the contract's storage slots. Send the request to https://base.therpc.io/YOUR_API_KEY (chain ID 8453, hex 0x2105). Because Base storage layouts mirror Ethereum's, each page is a map of keccak-hashed slot keys to their {key, value} pairs, with a nextKey cursor you feed back as startKey to walk the rest of the contract.

Use cases

• Dump the full storage layout of a Base contract at a precise execution point — paging from startKey to the final nextKey — for a post-mortem after an unexpected on-chain event.
• Verify slot assignments in an upgradeable proxy (common in Base DeFi deployments like Aerodrome) against the expected layout to catch a misaligned implementation slot.
• Compare a contract's storage before and after a suspicious transaction by reading at index n-1 and index n within the same Base block.

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_storageRangeAt",
7    "params": [
8        "0x0000000000000000000000000000000000000000000000000000000000000000",
9        0,
10        "0x0000000000000000000000000000000000000000",
11        "0x0000000000000000000000000000000000000000000000000000000000000000",
12        5
13      ],
14    "id": 1
15  }'

Try it live in the Base playground.

Errors & troubleshooting

Common pitfalls

• Slots come back keyed by their raw keccak256 hash, so mapping and dynamic-array entries are not human-readable — you must recompute keccak256(key . slot) yourself to match a value back to a Solidity variable.
• Reading any historical Base block requires an archive node; a pruned node only holds recent state and will return "block not found" for older blocks.
• A busy Base contract can hold thousands of slots; always pass a sensible limit and follow nextKey rather than trying to pull the entire trie in one call.

Supported networks

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

See also

• debug_traceTransaction
• debug_traceCall
• trace_replayTransaction

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_storageRangeAt","params":["0x0000000000000000000000000000000000000000000000000000000000000000",0,"","0x0000000000000000000000000000000000000000000000000000000000000000",10]}'