eth_call on Optimism
Executes a message call against the EVM without creating a transaction — the backbone of every contract read (balanceOf, totalSupply, etc.). Returns the call's return data.
Runs against a chosen block's state with no gas paid; override from/value/block to simulate a sender or a past state. It surfaces the contract's revert reason, which is how you catch errors like 'insufficient allowance' before sending a real tx.
Optimism endpoint (public — no key)
https://rpc.nodeflare.app/op/publicMethod
eth_call
Cost
5 CU
Chain ID
10
Block time
~2 s
Finality
~2 s soft · L1-final ~13 min
Contract calls on Optimism
eth_estimateGas covers L2 execution; the L1 data fee is added at inclusion. For calldata-heavy calls, compression (post-Ecotone blobs) keeps the L1 component modest.
Parameters
[callObject, blockNumber|tag]cURL
curl https://rpc.nodeflare.app/op/public \
-X POST \
-H 'content-type: application/json' \
-d '{"jsonrpc":"2.0","method":"eth_call","params":[{"to": "0x0b2c639c533813f4aa9d7837caf62653d097ff85", "data": "0x18160ddd"}, "latest"],"id":1}'The example targets the USDC contract on Optimism — you can run it as-is.
ethers.js
import { ethers } from 'ethers';
const provider = new ethers.JsonRpcProvider(
'https://rpc.nodeflare.app/op/public'
);
const result = await provider.send('eth_call', [{"to": "0x0b2c639c533813f4aa9d7837caf62653d097ff85", "data": "0x18160ddd"}, "latest"]);Try it live
Runs the example above against the public Optimism endpoint — straight from your browser.
eth_call on Optimism — FAQ
How do I call eth_call on Optimism?
POST a JSON-RPC 2.0 request with "method": "eth_call" to NodeFlare's Optimism endpoint at https://rpc.nodeflare.app/op/public. No API key is required for the public endpoint.
What does eth_call cost on the free tier?
eth_call is weighted at 5 compute units per call. The free tier includes 2,000,000 CU/month, so that is roughly 400,000 eth_call calls per month — no credit card.
Is eth_call available on the public Optimism endpoint?
Yes. eth_call works on the public Optimism endpoint (https://rpc.nodeflare.app/op/public) with no API key, rate-limited per IP. A free key adds higher limits and a dedicated path.
Anything Optimism-specific to know when using eth_call?
eth_estimateGas covers L2 execution; the L1 data fee is added at inclusion. For calldata-heavy calls, compression (post-Ecotone blobs) keeps the L1 component modest.
Call eth_call on Optimism with a free key
2,000,000 compute units/month, heavy methods unlocked, every chain included. No credit card.
Get your free API key →