For providers

Charge FB per call. Keep the keys.

Wrap any HTTP route once. Buyers pay on Fractal. Funds land on your xpub. We verify settlement — we never hold money.

Get an API key →MarketplaceOpen source on GitHub
non-custodiallocally verifiedFractal Bitcoin FB · readable in ≈$

API keys were a human workaround

Subscriptions and prepaid credits assume a person with a browser. Agents need a turnstile that speaks HTTP.

Before
  1. Buyer creates an account
  2. Card / KYC / credit packs
  3. You store their API key forever
  4. Chargebacks and prepaid leftovers
With x402.fb
  1. Buyer (or agent) just calls you
  2. 402 states the FB price in sats
  3. One on-chain payment unlocks the call
  4. You earn per request to your wallet

How you get paid

One ordered exchange. Same ritual humans and agents both complete.

01

Request

An agent or app hits your endpoint. No API key from the buyer.

02

402

Your server returns a price and a fresh address derived from your xpub.

03

Pay

One FB transaction — you get paid, facilitator fee is a second output.

04

200

We verify outs (prefer rawTx). Your handler runs. Funds never touched us.

For providers

Sell any endpoint, earn in FB

Your server holds an API key to our facilitator — not private keys, not customer balances.

  • → Data, compute, an LLM call, a file — anything HTTP returns
  • → Paid straight to your xpub, fresh address per call
  • → You set the sat price; humans see ≈$
Get an API key →
One line of middleware
import { requirePayment } from "os-x402/sdk";

app.get("/v1/inference",
  requirePayment({
    facilitatorUrl: process.env.X402_API,
    apiKey: process.env.SVC_KEY,
    price: 10_000
  }),
  (req, res) => res.json({ out: model(req) })
);

Hosted rail. Open protocol.

fb-exact + SDKs are MIT. Self-host the facilitator, or use ours and skip ops. The marketplace is how buyers find you.

Open source on GitHub →Marketplace

Straight answers

Do you hold my funds?

No. Payments go to addresses derived from your xpub. We only receive a separate facilitator fee output when you use our host.

Is this the same as Coinbase x402?

Same idea — HTTP 402 — different settlement. They lean stablecoins on EVM/Solana. We settle native FB on Fractal, UTXO-native.

Can I run this without you?

Yes. The scheme and SDKs are open source. Point requirePayment at your own facilitator URL.

What do buyers need?

A Fractal wallet (UniSat for humans; WIF / agent SDK for machines). No email account on our side for payments.