eth_getCode

eth_getCode returns the EVM bytecode deployed at an address on Arbitrum One, the Optimistic Rollup (chain ID 42161) where gas is paid in ETH and the Nitro/ArbOS stack runs the same EVM bytecode you would deploy on Ethereum L1. Point your call at https://arbitrum.therpc.io/YOUR_API_KEY, pass an address and a block tag, and the method returns the deployed bytecode at that address as of the specified block — or 0x if the account holds no code there.

Use cases

• Tell contract accounts from EOAs by checking whether the result is 0x — useful before routing a transfer or a contract call on Arbitrum One.
• Confirm a freshly deployed contract matches the expected bytecode after a Nitro deployment, comparing against the source-compiled artifact on Arbiscan.
• Spot proxy contracts by inspecting bytecode patterns such as EIP-1167 minimal proxies or EIP-1967 transparent proxies common across Arbitrum DeFi like Aave and Uniswap.
• Audit whether a contract still held code (or had been self-destructed) at a specific historical block.

Parameters

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": "eth_getCode",
7    "params": [
8        "0x0000000000000000000000000000000000000000",
9        "latest"
10      ],
11    "id": 1
12  }'

Try it live in the Arbitrum One playground.

Errors & troubleshooting

Common pitfalls

• A 0x result means "no code here" — it cannot, on its own, distinguish a plain EOA from a contract that was self-destructed; cross-check with eth_getTransactionCount or history if you need to know which.
• For a proxy you get the proxy's own bytecode, not the implementation's; read the EIP-1967 implementation slot with eth_getStorageAt, then call eth_getCode on that address.
• Querying an old Arbitrum block requires an archive node; against a pruned node a historical block returns a missing-trie-node error.

Supported networks

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

See also

• eth_getStorageAt
• eth_getProof
• eth_call
• eth_getBalance

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":"eth_getCode","params":["0x0000000000000000000000000000000000000000",""]}'