eth_estimateGas on BOB
Simulates a transaction and returns the gas it would consume, without broadcasting it. Wallets call this before signing to set a sensible gas limit.
It simulates once at current state, so a tx whose cost depends on other pending txs can be under-estimated — pad the result (e.g. +20%). On L2s the figure covers L2 execution only; the L1 data fee is added at inclusion.
BOB endpoint (public — no key)
https://rpc.nodeflare.app/bob/publicMethod
eth_estimateGas
Cost
5 CU
Chain ID
60808
Block time
~2 s
Finality
~2 s soft · L1-final ~13 min
Contract calls on BOB
Standard OP-Stack semantics; all EVM tooling works. Bitcoin-related precompiles/light-client contracts are regular contracts from the RPC's perspective.
Parameters
[callObject]cURL
curl https://rpc.nodeflare.app/bob/public \
-X POST \
-H 'content-type: application/json' \
-d '{"jsonrpc":"2.0","method":"eth_estimateGas","params":[{"to": "0x0000000000000000000000000000000000000000", "data": "0x"}],"id":1}'ethers.js
import { ethers } from 'ethers';
const provider = new ethers.JsonRpcProvider(
'https://rpc.nodeflare.app/bob/public'
);
const result = await provider.send('eth_estimateGas', [{"to": "0x0000000000000000000000000000000000000000", "data": "0x"}]);Try it live
Runs the example above against the public BOB endpoint — straight from your browser.
eth_estimateGas on BOB — FAQ
How do I call eth_estimateGas on BOB?
POST a JSON-RPC 2.0 request with "method": "eth_estimateGas" to NodeFlare's BOB endpoint at https://rpc.nodeflare.app/bob/public. No API key is required for the public endpoint.
What does eth_estimateGas cost on the free tier?
eth_estimateGas is weighted at 5 compute units per call. The free tier includes 2,000,000 CU/month, so that is roughly 400,000 eth_estimateGas calls per month — no credit card.
Is eth_estimateGas available on the public BOB endpoint?
Yes. eth_estimateGas works on the public BOB endpoint (https://rpc.nodeflare.app/bob/public) with no API key, rate-limited per IP. A free key adds higher limits and a dedicated path.
Anything BOB-specific to know when using eth_estimateGas?
Standard OP-Stack semantics; all EVM tooling works. Bitcoin-related precompiles/light-client contracts are regular contracts from the RPC's perspective.
Call eth_estimateGas on BOB with a free key
2,000,000 compute units/month, heavy methods unlocked, every chain included. No credit card.
Get your free API key →