Subscription Required

x402-superfluid is an open, neutral standard for internet-native subscriptions. It extends x402 with continuous payment streams, enabling lasting trust in the agentic economy.

→ Access subscription-gated content with one line of code

// Client: Just use x402-axios middleware
import { withPaymentInterceptor } from 'x402-axios';

const x402Client = withPaymentInterceptor(
  axios.create({ baseURL: 'https://api.example.com' }),
  walletClient
);

// Make request - middleware handles everything automatically!
const response = await x402Client.get('/resource', {
  params: { account: userAddress, recipient: recipientAddress }
});

console.log(response.data); // Access granted with active stream!

That's it! The middleware handles 402 responses, payment signing, and retries automatically. No manual balance checking, permission granting, or payment handling needed.

What's x402-superfluid?

x402 is an open standard for internet-native payments. But it only handles one-time transactions. Real relationships between service providers and users aren't one-time—you want continuous access, cancelable anytime.

Superfluid payment streams power exactly that. Combined with x402, x402-superfluid brings continuous subscription payments to the internet natively—an end-to-end subscription infrastructure that brings equity between creators and consumers, regardless of whether they are human or AI agents.

Learn About Money Streaming View on GitHub

It's how the internet should be: open, free, and effortless

Zero protocol fees

x402 is free for the customer and the merchant—just pay nominal payment network fees

Zero gas for users

Users only sign EIP-712 based signatures for authorization. Facilitator handles wrapping and stream creation

Zero wait

Money streams at the speed of the internet with real-time continuous payments that you can cancel anytime

Zero friction

No accounts or personal information needed. One-time ACL permission grant enables signature-only payments

Zero centralization

Anyone on the internet can build on or extend x402 with Superfluid. Open facilitator pattern

Real-time streaming

Continuous payment flows that update in real-time, perfect for pay-per-use APIs

We need a new way to transfer value on the internet...

The old way of doing payments is barely working for a human world, let alone an agentic future. x402 + Superfluid does in moments what existing systems can't do at all.

The old way

Create account with new API provider

Time consuming setup

Add payment method to API provider

KYC required, delaying access and requiring approval

Buy credits or subscription

Prepaid commitment → overpay or run out of funds

Manage API key

Security risk → must store and rotate keys

Make payment

Slow transactions, chargebacks, fees

With x402 + Superfluid

Client sends HTTP request and receives 402: Payment Required

Server checks for active Superfluid stream. If none exists, returns 402 with payment requirements

Client grants ACL permissions (one-time, on-chain)

User grants facilitator permission to create streams on their behalf. This enables signature-only stream creation going forward

Client signs EIP-3009 authorization (signature-only, no gas)

User signs payment authorization. Facilitator handles wrapping USDC→USDCx and creating stream. No gas fees for user

Facilitator processes payment and creates stream

Facilitator wraps USDC to USDCx, checks ACL permissions, and creates continuous payment stream. API access granted instantly

Continuous payment stream enables ongoing access

Money flows in real-time as services are consumed. No API keys, no repeated transactions, no subscriptions