Pay per token,
not per month.
paypurr is the open micropayments protocol for AI agents on Hyperliquid. Charge a fraction of a cent per request. Settle on-chain in one block. One HTTP header — no invoice, no Stripe, no chargebacks.
Three actors. One header. Sub-second settlement.
paypurr sits between buyer and seller as a stateless metering layer. Every API call carries a signed price tag; settlement happens on Hyperliquid L1 the moment the response is sent.
X-Paypurr-Max: 0.00001
X-Paypurr-Sig: 0x9a3f…verify → lock
forward → charge
finalize · 1 block@paypurr.meter({
price: 0.00000125
})Twelve lines. No webhook. No reconcile job.
If you can write an Express handler, you can sell inference. The SDK exposes one function — meter() — and inherits the rest from your stack.
// 1. price an endpoint import { paypurr } from "paypurr"; app.post("/v1/inference", paypurr.meter({ price: 0.00000125, // USDC asset: "USDC", seller: process.env.WALLET, }), async (req, res) => { const out = await llm(req.body); res.json({ out }); }); // → fee deducted on response // → settled on Hyperliquid L1
- →Per-call pricingSet a price per endpoint, per token, or per millisecond. Override at runtime.
- →Native USDCSettles in USDC on Hyperliquid. Bridge in/out from L1 in one tx.
- →Built-in refundsIf your endpoint 5xx's, paypurr returns the lock automatically.
- →Replay protectionEvery signature is single-use, scoped to one request hash.
- →Open specRFC-style protocol doc. Implement your own meter if you want.
Anything an agent should pay for, priced per call.
paypurr is general-purpose. If you can wrap it in an HTTP handler, you can sell it. Six patterns we expect to see early.
Zero protocol fee. Zero platform cut. You keep all of it.
paypurr is open infrastructure. We don't take a percent of your inference revenue and we don't charge a protocol fee on top of gas. Compare what a million calls actually costs you.
| Provider | Protocol fee | Platform cut | Settle time | Refunds | Cost · 1M calls @ $0.0001 |
|---|---|---|---|---|---|
| paypurr | $0.00 | 0% | 1 block | automatic | $0.00 + gas |
| Card processor | $0.029 + 30¢ | — | 2–7 days | 15–30 days | can't bill |
| L1 ETH micropay | ~$0.40 (gas) | — | 12s | manual | $400,000 |
| Off-chain credit ledger | 2–5% | 2–5% | monthly | net-30 | $2,000–5,000 |
Settlement-grade by construction.
paypurr is non-custodial: we never hold your keys, your float, or your customer balances. Funds move buyer→seller via a Hyperliquid escrow contract that's fully open-source.
Non-custodial escrow
Buyer locks funds in a per-session vault. paypurr can only release to a pre-signed seller address. No protocol multisig, no upgrade keys.
Single-use signatures
Every charge is bound to a request hash + nonce. A leaked signature is worth nothing — replays are dropped at the meter.
Spend caps & circuit breakers
Buyers set per-minute and per-day ceilings on every agent wallet. Hit the cap, requests 402 instantly — no surprise drain.
On-chain receipts
Every charge produces a verifiable Hyperliquid tx. Pull invoices any time — they're public, immutable, and reconcile themselves.
Frequently asked.
Why Hyperliquid?
+What happens if my endpoint errors?
+Can I price per output token, not per request?
+What does paypurr take?
+How do I withdraw to fiat?
+Charge in twelve lines.
Pay nothing to the protocol.
Install the SDK, wrap one handler, deploy. No KYC for testnet — mainnet onboarding takes about ninety seconds.