x402 Protocol: A New Era of Internet Payments at the Intersection of AI and Web3

Original Title: "x402 Protocol: A New Era of Internet Payments at the Intersection of AI and Web3"

Original Source: web3 Xiaohuolong

In 1994, the sale of a CD online marked the dawn of human e-commerce. Thirty years later, a pair of jeans autonomously purchased by AI is quietly ushering in the era of the machine economy.

When AI agents independently complete a transaction for the first time, the underlying logic of internet payments is undergoing a silent revolution. At the intersection of cryptocurrency and artificial intelligence, the x402 protocol has emerged. It not only redefines the boundaries of payments but also builds essential infrastructure for the autonomous machine economy.

From Dormant Protocol to AI Economic Foundation: The Technical Reconstruction of x402

HTTP 402 status code—"Payment Required"—has existed in internet foundational protocols since the 1990s but remained unused for a long time. In May 2025, the Coinbase Developer Platform team reactivated this code. The emergence of the x402 protocol solves the most critical bottleneck of the AI economy era: value exchange between machines.

The core breakthrough of the protocol lies in abstracting payments into a machine-readable standardized interface. When AI assistants need to call paid APIs or complete transactions, they no longer rely on traditional human payment processes—registering accounts, linking bank cards, or waiting for manual review. Instead, payment instructions are embedded directly into HTTP requests, utilizing stablecoins like USDC for instant settlement.

This technical architecture demonstrates multiple advantages: minimal integration enables developers to quickly deploy payment functions; chain-agnostic design supports multi-blockchain environments such as Base and Solana; near-zero fees make micropayment scenarios feasible, with settlement times reduced to the 200-millisecond level.

Ecological Explosion: From Proof of Concept to Market Adoption

Market validation is often more convincing than technology itself. The first token $PING based on the x402 protocol on the Base chain triggered a chain reaction throughout the ecosystem. Its minting mechanism is simple yet efficient—users send about 1 USDC to a specific address to mint 5,000 $PING tokens. This low-threshold participation method quickly ignited market enthusiasm.

Data speaks for itself: The market value of $PING exceeded 30 millions USD in a short period, with a 24-hour increase of more than 8 times. More importantly, this brought real stress testing to the x402 protocol—over the past 7 days, protocol transaction volume surged by 701.7%, transaction value grew by 8,218.5%, and about 31,000 new addresses joined the ecosystem.

The success of $PING is just the tip of the iceberg. The entire x402 ecosystem is rapidly expanding: Questflow has built a multi-AI agent work sequencing layer and secured 6.5 millions USD in seed funding; PayAI provides multi-chain payment service support including Solana; Kite AI has created an "intelligent agent internet foundational transaction layer" and completed a 33 millions USD funding round in September this year, led by PayPal Ventures and General Catalyst.

Giant Perspectives: Why Infrastructure Builders Are Betting Big

Ethereum Foundation's strategic positioning was clearly articulated at the ETHShanghai 2025 conference. Co-Executive Director Tomasz Stanczak revealed the infrastructure blueprint for the future AI agent economy: ERC-8004 as the agent function standard, covering identity, reputation, and claim verification; while x402 specifically defines the payment protocol between agents. Together, they form the technical foundation of the autonomous machine economy.

Coinbase, as the initiator, also has clear strategic intentions. The deep integration of the x402 protocol with the Base chain positions Coinbase at the core of the payment layer in the upcoming AI agent economy. As AI agents shift from passive tools to active economic participants, x402 is poised to become a key bridge connecting traditional finance and the crypto world.

The entry of traditional payment giant Visa is even more intriguing. By incorporating x402 into its Trusted Agent Protocol framework, Visa not only addresses the security issues of AI agent transactions but also effectively acknowledges the irreplaceability of crypto payments in the machine economy. This integration of traditional finance and crypto infrastructure marks x402's transition from fringe innovation to mainstream adoption.

Challenges and Evolution Path: From Early Adoption to Universal Applicability

Despite its broad prospects, the x402 protocol still faces substantial challenges on its path to mainstream adoption. Merchant adoption is the first key obstacle—more businesses need to be encouraged to accept and integrate blockchain-based payment systems; regulatory compliance is another major test—finding viable paths through complex regulations across different global jurisdictions; user experience is equally critical—further lowering the usage threshold so that non-technical users can also access it seamlessly.

However, these challenges are being gradually overcome. The continued investment of industry leaders like Coinbase, deep cooperation with infrastructure providers such as Cloudflare, and the ever-expanding developer community together form the support network for the ongoing evolution of the x402 protocol.

From a technology maturity curve perspective, x402 is at a critical stage transitioning from the innovation trigger phase to the bubble expansion phase. Excessive market enthusiasm may cause short-term volatility, but in the long run, the core problem it solves—autonomous value exchange between machines—will become increasingly important as the AI economy expands.

Conclusion: The Silent Revolution of Infrastructure

What the x402 protocol represents is far more than just an optimization of payment methods; it is a paradigm shift in the value exchange layer of the internet. When transactions between machines become as natural and smooth as data transmission, we will truly enter the gateway to the next-generation internet economy.

History tells us that truly revolutionary infrastructure is often underestimated in its early days until it becomes an indispensable part of societal operations. This was true for the power grid, true for internet protocols, and x402 is likely following the same path. At the intersection of the two major technological waves—AI and blockchain—a silent revolution shaping the future economic landscape has already begun.