Overview

Quicknode supports two wallet-based payment protocols that let any application or AI agent access blockchain infrastructure without creating an account or managing API keys. Both protocols build on HTTP 402 Payment Required but take different approaches to payment negotiation and settlement.

• x402 is an open standard by Coinbase. Quicknode maintains client libraries (@quicknode/x402, @quicknode/x402-solana) that handle authentication and payment automatically. The x402 proxy is available at x402.quicknode.com.
• MPP (Machine Payments Protocol) is an IETF Internet-Draft by Tempo Labs and Stripe. It uses standard HTTP authentication headers and supports multiple payment methods. The MPP proxy is available at mpp.quicknode.com.

Both protocols provide access to all supported blockchain networks.

Comparison

	x402	MPP
Origin	Coinbase (open-source spec)	Tempo Labs + Stripe (IETF Internet-Draft)
Wire format	Custom payment headers	Standard HTTP auth scheme (WWW-Authenticate / Authorization / Payment-Receipt)
Payment methods	Stablecoins (USDC, USDG)	PathUSD (Tempo), USDC (Solana), Stripe cards, Lightning BTC, custom
Billing patterns	Pay-per-request ($0.001/request) or credit drawdown ($10/1M requests)	Charge ($0.001/request) or session ($0.00001/request via off-chain vouchers)
Session support	Credit drawdown with SIWX auth and JWT sessions	Native payment channels with off-chain vouchers and batched settlement
SDKs	@quicknode/x402, @quicknode/x402-solana	mppx (TypeScript), solana-mpp
Protocols	JSON-RPC, REST, gRPC-Web, WebSocket	JSON-RPC, REST, gRPC-Web, WebSocket
Status	Alpha	Alpha

x402

x402 on Quicknode supports two access patterns:

• Pay-per-request: $0.001 per request. No authentication, no session state. Each request is self-contained using the standard x402 protocol.
• Credit drawdown: Authenticate once with SIWX (Sign-In with X), purchase a credit bundle ($10 for 1,000,000 requests), and consume credits per call. Better cost economics for sustained usage, and required for gRPC-Web and WebSocket.

Payment is accepted in USDC (Base, Polygon, Solana) or USDG (XLayer). The payment network is decoupled from the RPC network, so you can pay on one chain and query another.

tip

For a step-by-step walkthrough, see the x402 Getting Started guide.

MPP

MPP (Machine Payments Protocol) on Quicknode supports two intent types:

• Charge: $0.001 per request. One on-chain settlement per call. The simplest integration path.
• Session: $0.00001 per request ($10 per million). The client deposits into an escrow contract and signs off-chain vouchers for each request. Settlement is batched.

Payment is accepted in PathUSD on the Tempo blockchain or USDC on Solana, as well as other payment methods such as Stripe cards or Lightning BTC. The mppx SDK polyfills fetch to handle 402 challenges automatically.

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