HTTP 402,
automated.
Payments that
move at machine
speed.
Everything you need
to automate HTTP payments.
402 Interceptor
Drop the middleware into any HTTP stack. MPP intercepts 402 responses, negotiates the payment header, and retries the request — all transparently.
Real-time Monitoring
Trace every payment. Full execution history with on-chain tx hashes and per-request cost breakdown.
Payment Context
Persistent payment state across requests. MPP tracks nonces, receipts, and settlement status automatically.
Spend Limits & Guards
Define per-request and per-session spend caps. Fine-grained control over which endpoints can trigger payments.
Four languages.
One protocol.
Native SDKs for every major backend stack. Each one is a thin middleware layer — no lock-in, no new infrastructure required.
Express & Fastify middleware
Drop-in middleware that intercepts HTTP 402 responses and automates on-chain payment negotiation. Works with any Express-style framework in seconds.
WSGI / ASGI payment layer
Native Python SDK for Django, FastAPI, and Flask. Intercepts 402 responses at the WSGI/ASGI layer and settles payments on-chain without blocking your handlers.
net/http middleware handler
Lightweight Go package that wraps any http.Handler. Detects 402 status codes, negotiates the MPP payment header, and retries the request after settlement.
Tower layer & CLI relay
Axum-compatible Tower middleware layer plus a standalone CLI relay for scripting and CI pipelines. Zero-copy payment headers, full async/await support.
From 402 response
to paid request in four steps.
Intercept
Middleware catches the HTTP 402 response before it reaches your application code.
Negotiate
MPP reads the payment header, resolves the price quote, and selects the on-chain settlement path.
Settle
The SDK broadcasts the payment transaction and waits for on-chain confirmation — all in the background.
Retry
The original request is replayed with the payment receipt attached. Your handler sees a normal 200.
Connect any chain.
Pay any API.
Native connectors for Base, Ethereum, Solana, and more. Build custom payment routes with the MPP SDK in minutes.
Build custom payment routes
Define any payment handler as a route your middleware can call. Connect to Base, Ethereum, Solana, and more.
mpp.route({
chain: 'base',
settle: async (tx) =>
wallet.send(tx)
})
Full REST + WebSocket API. Stream payment events and settlement confirmations directly into your product.
Auditable payments
from day one.
Every payment is logged on-chain, every negotiation is traceable. Built for teams that need compliance and cost visibility without compromise.
On-chain Receipts
Every payment settled with a verifiable tx hash
Full Audit Trail
Every 402 negotiation logged with full traceability
Real-time Observability
Monitor, debug, and replay any payment flow
Built for developers.
Payments that just work.
Payments settling
24 / 7, on-chain.
At any moment, thousands of HTTP 402 responses are being intercepted, negotiated, and settled on-chain — transparently, without human intervention.
Start automating
HTTP payments today.
Drop MPP middleware into your stack and let the protocol handle every 402 — negotiation, settlement, and retry included.