MPP vs x402: Two HTTP-Native Ways for Agents to Pay

Short answer: MPP and x402 both let software pay over HTTP without a human in the loop, but they settle differently. x402, from Coinbase (6 May 2025, Apache 2.0), revives the HTTP 402 status code and settles stablecoins on-chain through a facilitator, which suits paying per request for APIs and content. MPP, the Machine Payments Protocol from Tempo and Stripe (18 March 2026), is built for programmatic agent billing, including sessions, recurring charges and micropayments, and settles across both stablecoins and fiat through Stripe Shared Payment Tokens. x402 is crypto-native settlement, MPP is multi-rail settlement through Stripe. They can coexist: an agent might discover a priced endpoint and pay through either rail.

Criterion	MPP	x402
Author / steward	Tempo and Stripe	Coinbase, now the x402 Foundation
Announced	18 Mar 2026	6 May 2025
Open-source status	Open standard (mpp.dev)	Open source, Apache 2.0
What it is	Programmatic machine payments over HTTP	HTTP-native payment rail
Payment type	Stablecoins and fiat via Shared Payment Tokens	On-chain stablecoins via facilitators
Transport	HTTP and MCP	HTTP 402 status code; MCP and A2A
Primary use	Agent session billing, recurring and micropayments	Pay per request for APIs, content and services
Settlement	Multi-rail (stablecoin and fiat via Stripe)	On-chain (Base, Polygon, Arbitrum, World, Solana)
Notable adoption	Browserbase, PostalForm, Parallel	AWS, Cloudflare, Circle, Coinbase

Criterion

MPP

x402

Author / steward

Tempo and Stripe

Coinbase, now the x402 Foundation

Announced

18 Mar 2026

6 May 2025

Open-source status

Open standard (mpp.dev)

Open source, Apache 2.0

What it is

Programmatic machine payments over HTTP

HTTP-native payment rail

Payment type

Stablecoins and fiat via Shared Payment Tokens

On-chain stablecoins via facilitators

Transport

HTTP and MCP

HTTP 402 status code; MCP and A2A

Primary use

Agent session billing, recurring and micropayments

Pay per request for APIs, content and services

Settlement

Multi-rail (stablecoin and fiat via Stripe)

On-chain (Base, Polygon, Arbitrum, World, Solana)

Notable adoption

Browserbase, PostalForm, Parallel

AWS, Cloudflare, Circle, Coinbase

Frequently asked questions

What is the difference between MPP and x402?

x402 settles stablecoins on-chain via facilitators, MPP settles stablecoins and fiat through Stripe Shared Payment Tokens. Both are HTTP-native machine payment standards.

Who is behind each?

x402 was created by Coinbase and moved to the x402 Foundation. MPP was co-authored by Tempo and Stripe and announced on 18 March 2026.

Can an agent use both?

Yes. They are not mutually exclusive, an agent can pay per request with x402 or run session-based billing with MPP depending on the endpoint.