HTTP 402 revived after 28 years of dormancy: Can the x402 protocol open a new world of AI Agent payments?

A Forgotten Button

The internet was still young in 1997, and even back then the HTTP protocol hid an “Easter egg”—the 402 status code, meaning “Payment Required.”

But this feature was never actually used. Why? Because at that time, there simply weren’t compatible payment methods. Credit card gateways were complex and had high fees; micropayments were a fantasy. And so, this status code was shelved for nearly thirty years.

Until recently, things changed.

Stablecoins have matured, Layer2 has driven on-chain transaction costs down to just a few cents, and AI Agents are emerging at scale, creating real micropayment demands. At this moment, a leading exchange seized the opportunity and reactivated this “dusty button,” launching the x402 protocol.

The core logic is straightforward: When an AI or user accesses paywalled content, there’s no need to register an account or jump to another page—just complete an on-chain USDC payment directly.

Sounds simple, but behind the scenes, an entire ecosystem is being rebuilt—from underlying protocol standards, to middleware infrastructure, to top-level applications, every layer is iterating rapidly.

So here’s the question: beyond the concept and meme coins, which projects in this system are actually up and running?

Protocol Layer: Teaching Machines to “Pay”

x402 is not a single standard, but a combination of modular protocols, solving three key problems: How do AI Agents communicate, how do they pay, and how do they establish trust?

At the bottom is the x402 protocol itself. It’s based on the HTTP 402 status code. When an AI accesses a paid API or content, the server returns a 402 response, and the AI automatically recognizes this and completes an on-chain stablecoin payment. The whole process requires no human intervention.

To enable AIs to cooperate, Google proposed the A2A protocol ((Agent-to-Agent)), standardizing communication and task handoff between agents. Anthropic has released the MCP protocol, which provides interfaces for AI to access tools and contextual data.

Based on MCP, Google also launched the AP2 payment protocol, allowing AI Agents to call services and pay automatically as needed, supporting both traditional payments and x402.

But here’s a technical hurdle: AI wallets usually don’t have ETH to pay gas fees. What’s the solution?

The answer is EIP-3009 extension. This standard allows users to authorize token transfers via signature, with no need to hold native coins to pay gas, completely solving the “AI wallet has no ETH” payment dilemma.

There’s also the ongoing ERC-8004, which establishes on-chain identities and reputation systems for AI Agents, recording execution history and trust scores, helping service providers judge whether an agent is reliable.

Simply put: The protocol layer is building a “language + currency + trust” system for AI, allowing machines to complete transactions, collaboration, and payments without human involvement. This is the first step for the whole ecosystem to work.

Infrastructure Layer: Who’s Doing the Heavy Lifting?

Protocols define the rules, but what actually enables payments is a full stack of infrastructure—verifying requests, processing transfers, coordinating services, and connecting AI with the blockchain.

Let’s start with Cloudflare. As a global cloud platform, it co-founded the x402 Foundation with a leading exchange, integrating the protocol into its CDN nodes and developer tools. Cloudflare provides a global distribution network and supports a “use first, pay later” deferred settlement mechanism, helping AI smoothly acquire resources and complete payments.

Next is the Facilitator ((payment aggregator)), the most crucial middleware in the system. It helps AIs complete a series of on-chain operations such as “payment on behalf, settlement, broadcasting.” Users or AIs just need to initiate an HTTP 402 request, and the Facilitator pays the gas, packages the transaction, and broadcasts it on-chain. Settlement uses the EIP-3009 standard: one authorization completes the USDC debit, with no need for manual signing or holding tokens.

From real data:

• The leading exchange remains the largest Facilitator, processing over 1.35 million transactions and serving 80,000 buyers
• PayAI is second, active on Solana and Base chains, with a cumulative transaction volume of $280,000 and even more users than the leading exchange
• Other players like X402rs, Thirdweb, and Open X402 are also competing for market share

In addition to Facilitators, native settlement blockchains designed for x402 have emerged. One representative is Kite AI, one of the first Layer1 chains to fully embed x402 payment primitives at the base layer, backed by the leading exchange’s VC, PayPal Ventures, and others. It doesn’t directly verify payments ((non-Facilitator role)), but provides an execution and settlement environment for x402 transactions, allowing agents to automatically initiate, receive, and reconcile on-chain payments via standardized authorization commands.

On the execution layer, besides Kite AI, Peaq also plays a key role. Peaq is a public chain focused on the machine economy, natively supporting the x402 protocol, enabling device-to-device and agent-to-agent automatic payments and settlements.

The representative of the x402 collaboration layer is Questflow—developers can publish agent tasks, set prices, and settle on-chain via x402, already in cooperation with several platforms.

There are also AurraCloud, Meridian, and others offering multi-chain settlement and custody services.

In summary: the infrastructure layer is building around three core issues—how to send requests, how to receive payments securely, and how to quickly deploy across different chains. This determines whether the whole payment system can truly function.

Application Layer: Who’s Actually Using It?

With protocol and infrastructure in place, it comes down to whether the application layer is moving.

Currently: very few live projects.

What’s visible so far:

• Daydreams: building an LLM inference platform based on x402 payments
• Heurist Deep Research: a Web3-native AI research platform where users pay USDC per query to automatically generate multi-page research reports
• Gloria AI: uses x402 to enable pay-per-use news
• Snack Money API: a micropayment interface for social platforms, enabling small tips around user identity
• tip.md: allows AI assistants to help users send crypto tips directly in chat, with USDC tips processed through MCP + x402
• Firecrawl: web scraping and cleansing API that converts websites into LLM-usable data, paid per call via x402

Overall, the x402 application layer is still in the exploratory phase; functional platforms are just getting started, and there’s no scale effect yet. The race is on to see who can first create truly usable, payable, and reusable products.

Meme: Hype and Risk Coexist

As the x402 concept heats up, a wave of “narrative-riding” meme projects have quickly emerged. The most representative is PING on Base, which reached a market cap of over $10 million on launch day.

Aside from PING, the community has seen tokens like “PENG” and “x402.” These memes are not core to the protocol, but they do bring attention, hype, and early liquidity.

However, the risks are clear: high price volatility, heavy speculation, and questionable project sustainability.

What Issues Still Remain for Adoption?

Although x402 is attracting attention, there are still hurdles to true adoption.

First, a lack of truly usable products. Most projects are still in testnet or proof-of-concept stages, with rough user experiences.

Second, a complex tech stack and high integration costs. x402 involves a whole new set of protocols, integrating payments, signature transfers, agent communication, and more, posing a high barrier for developers.

Third, compliance risks. The “accountless, no page jump” payment is efficient, but it bypasses traditional payment system KYC/AML requirements, which may raise regulatory concerns in some regions.

Fourth, network effects have not yet formed. The core of a payment protocol is ecosystem collaboration, but currently, few services and platforms have integrated x402, and the ecosystem has not yet become self-sustaining.

There are several technical and real-world hurdles to overcome before it can truly land.

Where Are the Participation Opportunities?

From a participation perspective, the long-term opportunities for x402 are mostly in infrastructure and key platform positions.

First is the base chain. x402 relies on EIP-3009, ERC-8004, and other Ethereum ecosystem standards, and Base is currently the main chain for deployment, with a strong stablecoin loop and developer-friendly environment, likely to incubate top products first. Solana also has strengths in high-frequency payments, making it suitable for agent microtransaction scenarios.

Second is native settlement blockchains like Kite AI, as well as payment aggregators and service platforms like PayAI, Meridian, and AurraCloud. They handle payment verification, gas sponsorship, and API integration. Once they become general gateways, their value will grow rapidly.

As for tokens, caution is advised. Currently, x402-related tokens are small and volatile, with many meme coins still in the narrative-driven phase. Projects with real payment adoption or platform utility are actually more worth watching.

What Do KOLs Think?

Market sentiment is divided, with many top builders and KOLs weighing in on the x402 ecosystem.

Haotian points out that the current x402 hype is mostly driven by meme speculation, and the real “main course”—technical adoption and ecosystem formation—hasn’t truly begun. Only after market filtering will quality projects emerge. Those treating x402 as a short-term speculation are missing the logic and rhythm of the whole track.

Laobai, from a historical perspective, notes that micropayments are not a new concept. From early Bitcoin and Lightning Network to Nano, IOTA, and BSV, the crypto world has tried to push small transactions many times, but large-scale adoption has always been elusive. The difference with x402 is that it has finally found the true subject in need of micropayments: AI Agents, not human users.

Danny takes an even broader view: the bigger potential behind x402 is as the payment infrastructure for the “machine economy.” From on-chain knowledge collaboration and API economy to AI-driven DAO governance, all these M2M ((machine-to-machine)) transaction needs naturally require a frictionless, accountless, and automatically executable payment layer.

Blue Fox Notes, from an architectural standpoint, believes that Facilitator, as the key link for payment verification and execution, is becoming one of the core infrastructures in the space. PayAI, the leading exchange, Pieverse, and others are already in a clear competitive landscape.

Zhixiong Pan raises a long-term question: Can agents truly “hold and pay with tokens”? This involves key mechanisms such as private key custody and permission management.

In summary: x402 may be experiencing volatility in hype right now, but for long-termists, it’s only just entering its true building phase.