An AI wrote a piece of code that needs data to verify.
It sent an HTTP request, and the server returned a number: 402.
Then it paid 0.001 USD with USDC. In less than a second, the data came back.
This transaction had no account, no password, no bank card, and no KYC. The entire process involved no one.
This is no longer science fiction. By the end of 2025, the x402 protocol handled over 100 million such transactions; in the last 30 days alone, there were an additional 15 million.
The 'payment code' that has been sleeping for thirty years
In 1990, the drafters of the HTTP protocol left a space for a status code: 402, Payment Required.
The meaning is straightforward - "You have to pay to enter here."
But this status code has never been officially used. It has just hung in the protocol document, dormant for thirty-four years.
The reason is not complicated: the first builders of the internet never thought that one day it would be machines paying the bills. Credit cards, bank accounts, KYC verifications - these payment infrastructures were designed for humans, completely ineffective in the face of autonomously running code.
AI Agents need to call APIs, purchase data, and acquire computing power at millisecond speeds; the account registration and fee thresholds of traditional payments are a dead wall.
In 2025, three conditions will be met simultaneously.
The total supply of stablecoins has surpassed 300 billion USD, with L2s like Base driving transaction costs down to sub-cent levels; AI Agent ecosystems led by OpenAI and Anthropic are beginning large-scale commercialization; Coinbase engineers have unearthed that dusty 402 and decided to activate it.
On May 5, 2025, Coinbase and Cloudflare officially released the x402 protocol. In September, they collaborated with Cloudflare to jointly announce the establishment of the x402 Foundation. A forgotten status code has returned to the center of the internet. Cloudflare manages about 20% of global web traffic - this means that from day one, x402 has had no shortage of infrastructure entry points.
Machines have learned to pay for the first time.
The design of x402 is surprisingly simple.
AI Agents initiate HTTP requests, the server returns a 402 status code, along with a payment request: how much, which chain, which token. The Agent uses EIP-712 encrypted signatures to authorize, embedding the payment information in the request header and resending it. The server returns resources after validation.
Less than a second throughout the process, no account, no subscription, no API Key.
This has transformed "payment" into a part of the internet. Like GET and POST, it is just an HTTP action; any service only needs to add a line of middleware to charge machines.
Data proves this logic is feasible. The protocol has been live for about seven months, processing over 100 million transactions. According to the Cambrian Network Q1 2026 report, there were over 15 million transactions in the last 30 days, with over 400,000 buyers and more than 80,000 sellers. The AI Agent community of Virtuals Protocol is the largest single source of transactions, autonomously settling collaboration fees between Agents on the protocol.
On December 11, 2025, x402 V2 went live. This upgrade pushed the protocol from 'usable' to 'user-friendly': supporting multi-chain parallelism such as Base, Solana, and Avalanche, introducing a Session mechanism (wallets become identity credentials, allowing repeated access without on-chain interaction each time), and bridging ACH bank transfers and credit card networks - the payment systems of Web2 and Web3 are connected for the first time in this protocol.
Google subsequently integrated x402 into the Agent2Agent (A2A) protocol and released the Agentic Payments Protocol (AP2); machines paying are becoming a consensus infrastructure for large tech companies.
Trust is the first hurdle in the Agent economy.
The payment issue is resolved, but there is an even more fundamental question without an answer.
"Commerce can’t happen if people don’t trust each other."
Davide Crapis is the AI head at the Ethereum Foundation and one of the co-drafters of ERC-8004. His judgment has pinpointed the core obstacle of the Agent economy: when an AI Agent needs to hire another Agent to complete a task, how does it know the other party is not a fraud? Where are the transaction records? How is trust transmitted?
ERC-8004 is Ethereum's answer to this issue. Drafted in August 2025, it officially went live on the Ethereum mainnet on January 29, 2026. It established three lightweight registries on-chain:
Identity Registry: Each Agent receives an on-chain ID based on ERC-721 NFT, which is portable, transferable, and cross-chain verifiable. The AgentCard (in JSON format) records capabilities, endpoints, and x402 payment support status.
Reputation Registry: On-chain archives of feedback signals between Agents - accuracy, timeliness, and reliability scores, with only indexes retained on-chain, and data hashes pointing to off-chain storage to reduce Gas costs;
Verification Registry: After task completion, the result data hash is on-chain for verification, enabling cryptographic proof of 'whether the task was genuinely completed'.
The drafting team spans four major crypto ecosystems: Marco De Rossi from MetaMask, Davide Crapis from the Ethereum Foundation, Jordan Ellis from Google, and Erik Reppel from Coinbase. EigenLayer, ENS, The Graph, and Taiko have all expressed support. Less than a month after going live on the mainnet, Ethereum mainnet registration of Agents surpassed 24,000, totaling about 49,000 across all EVM chains.
A typical workflow is as follows: Agent A discovers a service provider through the ERC-8004 identity registry, filters the reputation registry to select high-scoring Agent B, completes payment with x402, and after the task is finished, attaches the payment record along with reputation feedback - the payment history becomes a credit anchor. This chain is what Cambrian Network refers to as the 'Agent economy operating system': payment + identity + reputation, three layers in one.
How deep is the water here?
The data looks good, but there are a few things to clarify.
Tokens and protocols are two different things.
The market cap of the x402 ecosystem token once surpassed 9 billion USD on CoinGecko, with daily trading volume exceeding 230 million USD. However, a large number of 'x402 concept coins' are Meme tokens that have no substantial ties to the protocol itself. Buying x402-related Tokens does not equate to buying into the growth of the x402 protocol. This market has always excelled at mixing narrative and reality, and this time is no exception.
Technical risks have not yet been resolved.
The EIP-712 signature mechanism of x402 requires continuous security audits. The ERC-8004 reputation registry faces threats of Sybil attacks - mass registration of fake identities, and the existing economic incentive mechanisms are still inadequate. There is economic tension between high-frequency micropayments (each 0.0001 USD) and L2 transaction fees (which can still reach 0.05 USD), as very small transactions can still be consumed by fees at this stage.
The protocol war is not over yet.
x402, Google’s AP2, and a16z's ACP coexist as three protocols. If developers split between these three standards, the network effects will be significantly diminished. Moreover, OpenAI and Anthropic can completely bypass on-chain protocols to build their own closed-loop payment systems - they have users, data, and scale advantages, which pose competitive pressure that x402 cannot ignore.
Regulatory aspects are another blank space. Who is the transaction subject in a payment autonomously initiated by an AI Agent? Where is the trigger point for KYC/AML responsibilities? No major jurisdiction has provided a definitive answer.
Summary
Someone once wrote a quote that fits well here: "The inscriptions of 2023 allow humanity to engrave value on-chain; the x402 of 2025 enables machines to autonomously pay for value online for the first time."
If HTTP connected global computers into an information network, the combination of x402 and ERC-8004 attempts to link billions of Agents into an open service and data market - no accounts needed, no approval required, one request, one payment, one result.
However, whether the protocol can win in fragmented competition, whether the trust mechanism can truly improve, and whether the Agent economy can transition from Demo to real business... these remain unresolved cases.
Before the narrative takes root, distinguishing between the 'value of the protocol' and the 'Tokens speculated around the protocol' may be the most important thing for each participant to clarify.