eth_getBalance

eth_getBalance returns the ETH balance of an account on OP Mainnet at a specified block — ETH is the native gas token of this OP Stack rollup. The value comes back as hex-encoded wei, so it reflects the bridged ETH an address holds on L2, not on Ethereum L1. Query https://optimism.therpc.io/YOUR_API_KEY (chain ID 10, 0xa) with an address and a block tag such as latest or finalized.

Use cases

• Show an account's ETH balance in an OP Mainnet wallet or portfolio UI.
• Confirm an address holds enough ETH for L2 execution gas plus the L1 data fee before estimating or submitting a transaction.
• Poll the balance at latest to detect incoming ETH payments on the rollup as blocks land every ~2 seconds.
• Audit a balance at a specific historical block (via an archive node) for accounting, reconciliation, or forensics.

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

Try it live in the Optimism playground.

Errors & troubleshooting

Common pitfalls

• Never pass the raw hex wei through Number() — an OP Mainnet balance above 2^53 wei loses precision; always use BigInt(value) and divide by 10n**18n for whole ETH.
• A balance at latest reflects unfinalized L2 state; for a system of record that must survive a reorg before L1 settlement, read at finalized instead.
• This returns only the native ETH balance — for an ERC-20 such as a Velodrome reward token you must eth_call the token contract's balanceOf.

Supported networks

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

See also

• eth_getTransactionCount
• eth_call
• eth_getProof

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":"eth_getBalance","params":["0x0000000000000000000000000000000000000000","latest"]}'