Original Title: Stripe's MPP vs. x402: What Actually Happened Today
Original Author: Nick Sawinyh, defiprime.com
Translated by: Peggy, Blockbeats

Editor's Note: Regarding how agents make payments, x402 and MPP provide almost opposite paths.

x402 follows a minimal protocol: it embeds payments directly into HTTP requests, implementing pay-per-request in the simplest way. No accounts, no intermediaries, resembling the open, permissionless design of the early internet, suitable for long-tail developers and decentralized scenarios.

MPP, on the other hand, maximizes the system: it solves high-frequency trading, risk control, and fiat currency access issues through sessions, streaming payments, and compliance systems. It does not pursue purity but rather prioritizes meeting real business needs, making it more suitable for enterprise-level and large-scale applications.

The difference between the two is essentially two solutions to the same problem: whether to make payment part of the protocol or layer it in the system.

Therefore, they are not in direct competition but rather spread across different spectra; x402 covers the long-tail needs of open networks, while MPP handles high-frequency and commercial traffic. In an agent economy that is yet to take shape, this differentiation may be inevitable.

Here is the original text:

HTTP status code 402 has been waiting for an application since it was defined in the HTTP/1.1 specification in the late 1990s. Its meaning is payment required. The original concept was to embed payment capability into the protocol layer of the web, allowing machines to purchase resources just like requesting web pages.

However, this concept has largely not been realized. Over the years, this status code has only occasionally appeared in some edge scenarios, such as Shopify's rate limiting responses and billing errors from Apple Mobile Me, but no one has truly constructed the micro-payment future it implies. Instead, we have credit cards, subscription paywalls, and API key mechanisms, which are essentially designed for humans who perform manual operations.

Today, this future has emerged in two competing implementation paths, which were released on the same day. Next, I want to outline what they are, their differences, and why Stripe is betting on both paths at the same time.

x402: A Simpler Solution

Coinbase officially launched x402 in May 2025, and its core idea can be described as radically minimalist. A client requests a resource; the server returns HTTP 402 and informs the client: how much payment is required, which token to use, and on which chain to make the payment. After completing payment on-chain, the client attaches the payment proof to the re-initiated request, and the server then delivers the resource.

It's that simple. There is no account system, no API key, and no subscription mechanism. Just one round trip of an HTTP request with a payment in between.

Currently, Stripe has provided native support for x402 in its payment system, allowing merchants to directly receive such payments through existing backends. However, in essence, x402 is still a protocol led by Coinbase, governed by the x402 Foundation co-initiated by Coinbase and Cloudflare in September 2025. The protocol is fully open-source (Apache 2.0 License) and offers SDKs in multiple languages such as TypeScript, Go, and Python.

Regarding support, Coinbase's official documentation shows that ERC-20 payments are currently supported on Base, Polygon, and Solana. The ecosystem is also exploring extending this support to other chains like Avalanche, Sui, and Near, albeit with varying degrees of maturity.

Regarding adoption data, this part is somewhat more complex. Coinbase indicates that x402 has processed over 50 million transactions through its Agentic Wallet infrastructure. This sounds impressive, but according to on-chain analysis data from Artemis cited by CoinDesk on March 11, the daily transaction volume is about 131,000 transactions, totaling approximately $28,000, with an average payment of only about $0.20, of which about half seems to be testing or gamified behavior rather than actual commercial transactions.

However, this may not be a bad thing. Because this protocol is initially designed for a market that has not truly come into existence yet, a world where AI agents conduct micro-payments (even less than 1 cent) for API calls and data inquiries. The merchants serving this market are just beginning to emerge.

For example, Google's Agentic Payments Protocol (AP2, part of the A2A framework) has integrated x402; Lowe's Innovation Labs demonstrated a demo where an AI agent can complete the entire process from product discovery and research to ordering. Meanwhile, World (initiated by Sam Altman) released AgentKit this week, adding human verification capabilities to x402 wallets.

The underlying core assumption is that as long as payments are made as lightweight as HTTP requests, application scenarios will naturally emerge. Whether this holds true remains to be verified.

MPP: Full Stack Solution

Stripe and Tempo chose a different path. The Machine Payments Protocol (MPP) was launched alongside the Tempo mainnet today. Unlike x402, which serves as a lightweight encapsulation layer over existing blockchains, MPP is specifically designed for the scenario of high-frequency trading agents.

Its core mechanism revolves around sessions. Unlike initiating a chain transaction for each resource request, the agent can authorize a spending limit all at once and continuously make micro-payments within that limit. If you are an AI that needs to query data sources thousands of times an hour, you definitely do not want to sign and broadcast a chain transaction each time, which is precisely what sessions are designed to solve.

The Tempo chain is also built around this need. It supports tens of thousands of transactions per second, has sub-second confirmation times, and does not have a native gas token. Users can directly pay fees using stablecoins, eliminating the cumbersome step of first purchasing some random token for transfer.

Another component worth understanding is the Shared Payment Tokens (SPTs) included in Stripe's Agentic Commerce Suite. This is not part of MPP itself but rather an extension mechanism of Stripe, which can be used in conjunction with it. SPT allows agents to securely transmit users' bank cards or wallet credentials to merchants without exposing actual data. These credentials are limited to one-time transactions and have time constraints, which can be understood as a type of programmable, self-destructing authorization. In practical usage, this means an agent paying through MPP can use USDC on Tempo or a user-bound Visa card, or even a combination of both.

According to a blog post about the Tempo mainnet launch, its partners include Anthropic, DoorDash, Mastercard, Nubank, OpenAI, Ramp, Revolut, Shopify, Standard Chartered, and Visa. The Block reported that when MPP was launched, over 100 services, including Alchemy, Dune Analytics, Merit Systems, and Parallel Web Systems, were already included in the payment catalog. Matt Huang, co-founder of Tempo and Paradigm, mentioned in an interview with Fortune that this field is still in its early stages, and the design goal of MPP is to eventually expand to more on-chain environments outside Tempo.

Why Stripe Supports Both Simultaneously

If you are already integrated with Stripe, the most practical answer is that you do not need to choose between the two.

Stripe supports x402 and MPP through two independent integration paths rather than abstracting them into a unified interface. For x402, its documentation mainly covers processes like generating recharge addresses, on-chain monitoring, and settling funds to Stripe accounts—you are responsible for returning 402 responses, while Stripe handles the underlying crypto payment infrastructure. Currently, it supports USDC on Base, with plans for expansion in the future. For MPP, merchants can receive session-based streaming payments through the same PaymentIntents API.

The Agentic Commerce Suite released by Stripe in December 2025 is built on these two payment tracks. Merchants simply need to upload their product catalogs, select AI agents they wish to integrate, and Stripe will manage product discovery, checkout processes, fraud prevention, and tax handling. Currently, URBN, Etsy, Coach, Kate Spade, and Ashley Furniture are already using it, and platforms like Wix, WooCommerce, BigCommerce, Squarespace, and commercetools have also completed integration.

Its strategy is quite clear: control the abstraction layer and allow underlying protocols to compete freely.

Comparison

From a macro perspective, these two protocols are doing the same thing: allowing machines to pay for resources via HTTP. But the real differences lie in the details.

x402 (Led by Coinbase) vs MPP (Stripe + Tempo)

Standardization
x402: Fully open-source (Apache 2.0), driven by the x402 Foundation for multi-party engagement (Coinbase, Cloudflare, Visa, Google).
MPP: Open standard, co-developed by Stripe and Tempo, part of Stripe's Agentic Commerce Suite.

HTTP Mechanism
x402: Revives HTTP 402 by initiating requests through the PAYMENT-REQUIRED header and completing retries with the PAYMENT-SIGNATURE.
MPP: Also uses a challenge-response mechanism, but employs the Payment HTTP Authentication Scheme (IETF draft), binding the challenge ID via HMAC.

Payment Layer (Rails)
x402: Designed to be chain-agnostic; currently supports Base, Polygon, and Solana, with other chains under exploration.
MPP: Based on the Tempo blockchain—a Layer 1 optimized for payments, supporting over 10,000 TPS, sub-second confirmations, and no native gas tokens; a long-term goal includes cross-chain compatibility.

Payment Methods
x402: Pure stablecoin, entirely on-chain.
MPP: Supports USDC on Tempo + SPT (Stripe's mechanism), enabling a mix of crypto and fiat (bank cards, wallets, BNPL).

Settlement Method
x402: On-chain settlement (approximately 200ms to several seconds), verified and settled by facilitators like Coinbase.
MPP: Sub-second confirmations on Tempo; Stripe automatically credits and processes compliance.

Merchant Integration
x402: Open-source middleware (Express, Hono, Next.js, etc.), enabling self-hosting or using facilitators.
MPP: Direct integration with Stripe's PaymentIntents API, with built-in risk control, taxation, refunds, and reporting.

Core Innovations
x402: Extremely simple, vendor-agnostic, similar to the Unix philosophy in the payment domain.
MPP: High throughput + fiat integration, enabling streaming payments, micro-payment aggregation, and programmable spending control based on SPT.

Key Partners
x402: Coinbase, Cloudflare, Google (A2A/AP2), Visa, World, Anthropic (MCP).
MPP: Stripe, Visa, Lightspark, Anthropic, DoorDash, Mastercard, OpenAI, Shopify, Revolut, Standard Chartered.

x402 is more like your preferred solution when building an open system: independent developer APIs, decentralized data markets, or any service that does not want to rely on payment processors. Its specifications could be written into a white paper, and integration only requires middleware and a wallet address. This purity is very appealing—even though the limitations of pure crypto also mean its audience is narrower.

MPP, on the other hand, is an entirely different paradigm. If your agent needs to perform hundreds or even thousands of transactions in a single session without wanting every single one to go on-chain, then it is a more reasonable choice. The session mechanism keeps most interactions off-chain until final settlement; Stripe's compliance system manages risk and tax; and the mixed payment mode of SPT allows agents to use both stablecoins and directly access users' Visa payment methods. It may not be as elegant, but it is closer to reality.

Interestingly, they are not entirely in competition. x402 covers long-tail open scenarios, while MPP caters to enterprise-level high-frequency traffic. Stripe's strategy is also quite clear: it does not bet on a single protocol but ensures that whichever path succeeds, funds will ultimately flow into Stripe's account system.

Current Situation: How Far Have We Progressed?

To be honest, there is still hardly any real-scale transaction happening.

According to the x402 release information from Coinbase, early partners include Hyperbolic (GPU inference payment) and Anthropic (MCP protocol integration). Stripe's blog mentions scenarios where agents pay per API call (e.g., CoinGecko). The Tempo launch directory had over 100 services. Cloudflare's Agents SDK has natively supported x402, and some small projects on Base L2 are also attempting to create payment gateways using x402.

However, overall: transaction volumes are small, the number of merchants is limited, and most activities are still at the experimental stage.

This is not surprising. Any new payment infrastructure follows this pattern in its early stages. The so-called partner list can sometimes show a significant gap between signing letters of intent and having services actually live, and these releases typically do not make this distinction clearly.

What deserves more attention are the heavyweight participants behind the infrastructure. Stripe processed $1.9 trillion in payments in 2025, with a year-on-year growth of 34%. Meanwhile, Coinbase, Cloudflare, Visa, Google, and a comprehensive network of partners surrounding Tempo have all entered the field.

In other words, the tracks have been laid. The only remaining question is: in 2026, will AI agents really need to engage in large-scale transactions on this track? Or is this more like laying fiber optics in 1998—demand hasn't emerged yet, but the infrastructure is already in place.

Which One Should You Choose?

If you are building an open, permissionless system—x402 is a more natural choice. No platform registration is needed, no payment processor integration is required; you can import middleware and link a wallet to receive payments. The downside is that compliance, risk management, and fiat settlement all need to be handled by yourself.

If you are already within the Stripe ecosystem and wish to integrate agent traffic—MPP is more appropriate. The session, streaming payments, fiat + crypto mix, and complete compliance system effectively resemble an upgrade in configuration rather than a system overhaul.

If you care about only one thing: no matter which protocol the agent uses, I still want to get paid. Then the answer is simple: use Stripe. It supports both.

HTTP 402 has finally come into play. It has just waited for nearly 27 years.

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