Frequently asked questions.

What is x402?

x402 is an open HTTP payment protocol. When a client requests a paid resource, the server replies with HTTP 402 Payment Required and a signed quote. The client signs an EIP-3009 USDC authorization, retries with the signed payment in the X-PAYMENT header, the server verifies on-chain, settles, and serves the data. ApiToll is an x402 seller: every paid endpoint follows this flow.

Do I need to sign up for an account?

No. There is no signup, no API key, no plan. The agent's wallet is the auth. Send a request, get a 402, sign, retry. That is the whole onboarding.

What does it cost?

Per call, in USDC on Base. Prices range from sub-cent micro-lookups (current launch services are $0.001-$0.002) up to dollars per call for premium data once partner services come online. The 402 challenge always carries the exact price. Your wallet refuses anything above its configured maximum.

Why USDC and not ETH or another token?

USDC is dollar-stable, widely held, native on Base, and the asset every x402 facilitator supports. No volatility surprises between quote and settlement.

What network is this on?

Base — Coinbase's L2. Mainnet for production, Sepolia testnet for the sandbox endpoints. Cheap gas, fast confirmations, USDC support out of the box.

How do I get a wallet for my agent?

See our wallet guide. Short version: a Coinbase Smart Wallet (passkey-based, no seed phrase) or a CDP Server Wallet (programmatic, key custody by Coinbase) both work.

How is x402 different from buying credits or topping up an account?

There is no account. You don't pre-fund anything with us. Each call is its own atomic on-chain settlement — your wallet pays at request time, we serve the response. You see every settlement on-chain. Stop using us and you stop spending; nothing held in escrow.

What's the sandbox?

Every paid service has a parallel /v1/sandbox/<service>/ endpoint on Base Sepolia. Same response shape as production. Costs test USDC (free from the Alchemy Sepolia faucet). Switch to production by removing /sandbox/ from the URL.

How do I integrate this in Node?

@x402/axios wraps Axios with the 402 / sign / retry round-trip. About 8 lines of setup. See the agent primer.

How do I integrate this in Python?

Use the x402 Python SDK or build the round-trip manually with requests + eth-account. The protocol is HTTP — no language is privileged.

What if a call fails?

If the payment fails (insufficient funds, malformed signature), you get a 4xx with a reason. If settlement succeeds but the upstream data lookup fails (e.g. unknown BIN), you still pay — that's the lookup attempt — and get a 404 with the reason. We log every settle to an immutable JSONL file; you can audit.

Can I rate-limit my own spend?

Yes — at the wallet level. Most x402 client libraries let you cap the maximum per-call price and the maximum total spend per session. We also rate-limit per-IP at our edge as a safety net.

How does this differ from a regular paid API?

See the comparison page. Short version: no signup, no key, no monthly minimum, no invoices, no rotation. The wallet is the identity, the on-chain settlement is the auth. Designed for autonomous software, not for humans filling out signup forms.

Where is ApiToll listed?

agentic.market (CDP's v2 Bazaar) — auto-listed when our facilitator settles paid calls. Also discoverable via /llms.txt, /.well-known/mcp.json, and /.well-known/agent.json.

How do I become a data partner?

See Early Access. We're taking 20 partners in the first wave. We do the implementation for free; you set the price and keep the revenue.

Who runs ApiToll?

ApiToll is a Rapaydo product, sibling to AgentPay. Operated by Daryn Louw out of Plettenberg Bay, South Africa. Email [email protected] for anything.