LogicNodes — Blocknative Gas API Migration

§ 01 — TRY IT KEYLESS (NO SIGNUP)

One curl. Real gas data from 100 analyzed blocks.

This is the exact free-trial endpoint — no API key, no account. It returns a signed EIP-1559 estimate derived from the last 100 blocks of eth_feeHistory on the chain you pass.

Request — keyless free trial

# No key required
curl -X POST https://logicnodes.io/free-trial/eip1559_gas_estimator \
  -H "Content-Type: application/json" \
  -d '{"chain":"base","speed":"fast"}'

Response — signed estimate

{
  "chain": "base",
  "speed": "fast",
  "max_fee_gwei": 0.1055,
  "priority_fee_gwei": 0.1,
  "max_fee_hex": "0x649cd60",
  "blocks_analyzed": 100,
  "all_speeds": { slow, standard, fast, instant }
}

Supported chains today: base, ethereum, polygon, arbitrum, optimism. Every response is EIP-191 signed by the LogicNodes oracle key so you can verify it wasn't tampered with in transit.

§ 02 — THE MIGRATION

One-line migration. Same response schema.

Before — Blocknative (sunsetting)

// Stops responding June 19, 2026
const res = await fetch(
  'https://api.blocknative.com/gasprices/blockprices',
  { headers: { Authorization: BN_KEY } }
);
const { estimatedPrices } = await res.json();

After — LogicNodes (live now, same schema)

// One-line swap. No auth header. Same response fields.
// Free: 100 calls/day per IP. Then $0.001/call via x402.
const res = await fetch(
  'https://logicnodes.io/gasprices/blockprices?chainid=1'
);
const { blockPrices } = await res.json();
// blockPrices[0].estimatedPrices →
//   { confidence, price, maxPriorityFeePerGas, maxFeePerGas }

web3.py / Python

# pip install requests — verified against the live endpoint
import requests

prices = requests.get(
    "https://logicnodes.io/gasprices/blockprices",
    params={"chainid": 137},  # 1, 10, 137, 8453, 42161
).json()["blockPrices"][0]["estimatedPrices"][0]

tx = {
    "maxFeePerGas": w3.to_wei(prices["maxFeePerGas"], "gwei"),
    "maxPriorityFeePerGas": w3.to_wei(prices["maxPriorityFeePerGas"], "gwei"),
}

ethers.js v6

// Fee overrides from the 99-confidence estimate
const { blockPrices } = await (await fetch(
  'https://logicnodes.io/gasprices/blockprices?chainid=8453'
)).json();
const p = blockPrices[0].estimatedPrices[0];

await contract.someMethod(args, {
  maxFeePerGas: ethers.parseUnits(String(p.maxFeePerGas), 'gwei'),
  maxPriorityFeePerGas: ethers.parseUnits(String(p.maxPriorityFeePerGas), 'gwei'),
});

	Blocknative	LogicNodes
Status	Shuts down June 19, 2026	Live
Data source	Proprietary	eth_feeHistory (100 blocks)
Auth	API key required	None — 100 free calls/day per IP, then $0.001 USDC (x402) or API key
Drop-in schema	—	Yes — identical blockPrices JSON at /gasprices/blockprices
Response signing	No	Yes — EIP-191 (on /free-trial and /call endpoints)
Try without signup	No	Yes — keyless free trial
Chains	40+ EVM	Ethereum, Polygon, Base, Arbitrum, Optimism

Supported chainid values: 1 (Ethereum), 137 (Polygon), 8453 (Base), 42161 (Arbitrum), 10 (Optimism). We list only the five chains our estimator serves today. We don't claim parity with Blocknative's full 40+ chain coverage — if you need a chain we don't list yet, tell us at the contact below and we'll prioritize it.

§ 03 — GET STARTED

Migrate before the lights go out.

Test keyless in your terminal right now, then grab a key when you're ready to wire it into production. The countdown above is live.

Quickstart → Read the docs → Code-level migration guide → Full worker catalog →

Questions on migration? Email [email protected].

Blocknative's gas API shuts down June 19, 2026.

One curl. Real gas data from 100 analyzed blocks.

One-line migration. Same response schema.

Migrate before the lights go out.