Pay per request

x402 RPC — no account, no API key

Pay for blockchain RPC calls in USDC on Base, Polygon or Arbitrum via the open x402 protocol — from $0.001 per call on all 22chains, served from our own bare-metal nodes. Built for AI agents and automated clients that can't stop to fill in a signup form.

Endpoint — every chain

https://rpc.nodeflare.app/{chain}/x402

POST without payment → HTTP 402 challenge in the PAYMENT-REQUIRED header. Machine-readable chain list at https://x402.nodeflare.app/.

Try the heavy path free first. Anonymous callers get 22 free heavy RPC calls a day — eth_getLogs, trace, debug — with no key and no wallet: one on every chain, or all on one. POST to /{chain}/public and they just work. After that, pay per call below or grab a free key.

1. Call

POST your JSON-RPC body. The 402 response quotes an exact USDC price for that call.

2. Pay

Your x402 client signs a USDC authorization and retries. Gas is covered by the facilitator.

3. Done

We serve the call from our own nodes and settle on-chain — the tx hash comes back in a header.

Pricing

Standard read, or a single heavy call (eth_getLogs, trace_*) — min $0.001$0.001
Batch of 20 × eth_getLogs (1,500 CU)$0.015
Batch of 100 standard reads$0.001

1 compute unit = $0.00001, minimum $0.001 per request — same CU weights as our plans. Heavy methods (eth_getLogs, trace_*, debug_*) included. You only pay for calls that succeed.

Try it in 60 seconds

import { wrapFetchWithPaymentFromConfig } from "@x402/fetch";
import { ExactEvmScheme } from "@x402/evm";
import { privateKeyToAccount } from "viem/accounts";

const account = privateKeyToAccount(process.env.PRIVATE_KEY); // USDC on Base
const pay = wrapFetchWithPaymentFromConfig(fetch, {
  schemes: [{ network: "eip155:8453", client: new ExactEvmScheme(account) }],
});

const res = await pay("https://rpc.nodeflare.app/base/x402", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ jsonrpc: "2.0", id: 1, method: "eth_blockNumber", params: [] }),
});

All 22 chains, one payment flow

The same x402 door also serves our Agent Intelligence endpoints — a unified data layer over the young chains the big indexers leave as empty shells.

ethereumEthereum/eth/x402baseBase/base/x402bnbBNB Chain/bnb/x402arbitrumArbitrum One/arb/x402optimismOptimism/op/x402hyperliquidHyperEVM/hl/x402avalancheAvalanche/avax/x402unichainUnichain/unichain/x402sonicSonic/sonic/x402polygonPolygon/polygon/x402lineaLinea/linea/x402mantleMantle/mantle/x402zircuitZircuit/zircuit/x402robinhoodRobinhood Chain/robinhood/x402xlayerXLayer/xlayer/x402soneiumSoneium/soneium/x402arbitrum-novaArbitrum Nova/nova/x402bobBOB/bob/x402inkInk/ink/x402cronosCronos/cronos/x402modeMode/mode/x402plasmaPlasma/plasma/x402

x402 RPC — FAQ

What is x402 RPC?

x402 is an open HTTP payment protocol (started by Coinbase, stewarded by the x402 Foundation) that uses the HTTP 402 status code to charge per request. x402 RPC means paying for individual blockchain JSON-RPC calls in USDC instead of creating an account and API key — the payment itself is the authorization.

How do I pay for RPC calls with x402?

POST your JSON-RPC call to https://rpc.nodeflare.app/{chain}/x402. The first response is HTTP 402 with the price in the PAYMENT-REQUIRED header. An x402 client like @x402/fetch signs a USDC authorization and retries automatically — your wallet only needs USDC on Base, Polygon or Arbitrum; gas is covered by the facilitator.

How much does x402 RPC cost?

Prices follow NodeFlare's compute-unit weights at 1 CU = $0.00001 with a minimum of $0.001 per request. A standard call like eth_blockNumber or one eth_getLogs costs $0.001; a batch of 20 eth_getLogs calls costs $0.015. You only pay for calls that succeed.

Can I authorize a maximum instead of paying a fixed amount per call?

Yes — every endpoint accepts two x402 schemes. The default, exact, quotes a fixed USDC price per call and signs a one-shot authorization (EIP-3009), with no pre-approval — the simplest path. upto lets a caller authorize a ceiling once (via a Permit2 approval) and then be settled the real per-request price, up to that max — useful for agents that would rather not price every call ahead of time. Both settle in USDC on Base, Polygon or Arbitrum; use whichever your x402 client supports.

Which chains support x402 RPC payments?

All 22 chains NodeFlare serves — over the same endpoint and one payment flow: Ethereum, Base, BNB Chain, Arbitrum, Optimism, Avalanche, HyperEVM, Polygon, and young chains like Robinhood Chain, Plasma, Ink, Zircuit, BOB, Soneium and Mode. On top of raw RPC, the same x402 door serves NodeFlare's Agent Intelligence endpoints (balances, portfolio, approvals, simulation, wallet report, token safety) — a unified data layer over the young chains the big indexers leave as empty shells.

Do AI agents discover x402 endpoints automatically?

Yes. Every NodeFlare x402 endpoint is cataloged in the x402 Bazaar, Coinbase's discovery layer for paid HTTP services. Agents search the Bazaar via its REST API or MCP server, find the chain they need, and pay per call autonomously — no signup flow to break on.

Go deeper

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