api.x402node.dev
GET https://api.x402node.dev/chain/tx-cost
Estimate the USD cost of a transaction (transfer, ERC20 transfer, approve, swap, NFT mint) on Base/Ethereum/Arbitrum/Optimism/Polygon from live gas price and native token price - lets agents decide whether an action is worth the fee before sending. gas cost, transaction cost, tx fee usd, how much gas, operation cost, fee estimate Accepts payment on Base or Solana — either network works.
Warnings
Unusual seller traffic This seller's paid usage looks manufactured: paid calls to trivial endpoints like ping or uuid, or near-identical payer counts on every endpoint. Its usage counts half.
How to buy
This endpoint takes pay-per-call payments over x402. Call it once without paying to see its live price; any x402 client then pays and retries automatically.
curl -i -X GET "https://api.x402node.dev/chain/tx-cost"
# HTTP/1.1 402 Payment Required: price, asset and payTo are in the responseRecent checks
| Checked (UTC) | Result | Status | Time | Live price |
|---|---|---|---|---|
| 2026-10-11 09:15 | Valid 402 | 402 | 309 ms | $0.005 |
| 2026-10-11 04:45 | Valid 402 | 402 | 45 ms | $0.005 |
| 2026-10-11 00:15 | Valid 402 | 402 | 44 ms | $0.005 |
| 2026-10-10 19:45 | Valid 402 | 402 | 53 ms | $0.005 |
Receipts
No test purchases yet. Graded test purchases are next on our list; until then every number here comes from unpaid checks.
What a check proves