A Beginner's Guide to the x402 Protocol: What is the recently popular x402?

In recent days, the x402 protocol has become extremely popular, and everyone is talking about x402. So what exactly is this thing? What opportunities are there in the future?

I quickly learned all the information on the market and sorted it out systematically here to share with everyone to learn together!

If we want to talk about x402, I think we still need to look at this protocol from a higher perspective and a larger track to understand the positioning of x402.

This has to start with stablecoin payments:

With the penetration of stablecoins, stablecoin payments have also emerged and exploded.

It can be divided into three categories as a whole:

B2B payment: clearing and settlement between institutions, enterprise-level payment

C2C payment: payment between individuals, point-to-point transfer

C2B payment: payment from individuals to merchants, purchase scenarios

Currently, stablecoin payments are mainly carried out in the above three scenarios, but there is also a huge potential market: AI payment. What are the big trends? The future is an intelligent era, and everything will be integrated with AI. AI agents will become essential tools for every individual and even for businesses. In the future, almost all consumer-side consumption and business-side settlements will be automatically performed by AI agents. Based on this ultimate state, what capability do AI agents currently lack?

It's actually payment.

You should know that payments in our traditional world must require real-name KYC. You must have an "identity" to open a bank account and then make payments.

AI Agent is a virtual entity. How can it possibly open an account and make payments?

At this time, the emergence of stablecoin payments just fills this gap. Blockchain is decentralized. Blockchain-based stablecoin payments allow AI agents to directly create addresses on-chain, equivalent to "opening a bank account," and use stablecoins to freely transfer funds, realizing the flow of value. At this point, we find that the AI ​​agent not only has an on-chain identity but also an on-chain account, truly controlling "property rights." This raises another question: what if there is currently no universal stablecoin payment standard? x402 was born.

Next, let's take a closer look at this protocol.

1. What is x402?

X402 is an open source payment protocol launched by Coinbase, the first compliant exchange in the United States, in May 2025. This protocol is based on the HTTP protocol (the underlying rules for web pages) and utilizes the "402 Payment Required" status code, hence the name x402. Simply put, x402, like WeChat Pay and Alipay, is essentially a payment channel/interface. However, x402 is designed specifically for AI. For example, if AI wants to purchase data, computing power, or API services, it can pay directly, eliminating a lot of intermediate steps. If you want to receive RMB, you have to connect to Alipay or WeChat Pay. If you want to receive USD, you can connect to Paypal or Stripe. If you want to receive USDT or USDC, you can connect to x402. Unlike WeChat Pay and Paypal, which are all centralized payment gateways, x402 is a decentralized payment method, and the money you receive goes directly into your own web3 wallet. 2. What problem does x402 solve? In 2025, with AI developing rapidly, AI agents will face a major problem: Like a super-intelligent assistant, AI can search for data, use APIs, and purchase computing power, but it can't log in to websites, enter passwords, or swipe cards like a human. Traditional payment methods (credit cards, PayPal) are too slow and complicated, and they charge a 2-3% fee, making them unsuitable for AI's "micropayment" needs (buying data for a few cents).

Therefore, the main problems solved by x402 are:

AI autonomous payment: AI can pay directly for services like humans, such as using 1 USDC to access a weather API, eliminating human intervention.

Micropayment Challenges: Traditional payment processing fees are high (such as credit cards charging 2% per transaction). x402 uses blockchain (mainly Base chain) and only charges ultra-low gas fees (a few cents), making it suitable for small transactions.

Simplified Process: No registration or authentication required, x402 makes payments as simple as sending messages. It's HTTP native, and developers can integrate it with just one or two lines of code.

Globally applicable: Using stablecoins (such as USDC), it can be used globally and there is no need to worry about exchange rates.

x402 is like giving AI a "digital wallet," allowing it to pay for things anytime, anywhere, saving time and effort, and it's also affordable!

x402 can be said to be the "last mile" of AI payment.

Third, how does x402 work? The core of x402 is to embed payments into the HTTP protocol (the language of web pages) and use blockchain (primarily Coinbase's Base Chain) for settlement. It sounds complicated, but it's actually like adding a "payment button" to a web page.

Briefly list the technical points:

HTTP 402 status code: The website says "Want to see the content? Pay first!" and returns a 402 status, telling you how much to pay (for example, 1 USDC) and where to pay (the address on the chain).

Blockchain payment: Use a digital wallet (such as MetaMask) to sign and pay, and the money goes directly to the Base chain (Ethereum's Layer 2, which is cheap and fast). Open Source Protocol: x402 is publicly available code (available on GitHub, coinbase/x402) and can be used by any developer, similar to a "free blueprint" for adding payment functionality to websites. Stablecoin-Powered: Payments are made in USDC (1 USDC = 1 US dollar), which is stable and globally accepted. Simply put, x402 is like installing an "Alipay QR code" on a webpage. The AI ​​can scan the code to pay, and the website will immediately give the AI ​​the money.

IV. The operation process of x402

To give a practical example, suppose you (or AI) want to use x402 to buy weather API data,

the process is as follows:

Initiate a request: You (or AI) visit a weather website and want to check the weather in Shanghai tomorrow.

Website responds with “402”: The website says “Data requires 1 USDC” and returns an HTTP 402 status code, along with payment details (amount, recipient address).

You pay: Use your MetaMask wallet to click, sign, and pay 1 USDC (like WeChat scan code payment). The transaction is confirmed on the Base chain, and the gas fee is only a few cents.

Get the data: After the website verifies that it has received the money, it will give you the weather data in seconds (for example, "Shanghai, 25°C, sunny").

The whole process can be summarized as follows: send a request → be informed of the payment → pay → retry the request → obtain the resource.

V. Why is x402 so popular recently?

When x402 was released in May 2025, it was just a niche project in the developer circle, but it suddenly "exploded into popularity" in October.

There are three core reasons:

Endorsement by major companies :

On October 17, Cloudflare and Coinbase established the "x402 Foundation", which gave x402 "official certification".

Cloudflare's servers now support x402 transactions, making it available to websites worldwide.

Google has incorporated x402 into the AP2 protocol (the AI ​​agent standard), and AWS, Anthropic, Circle, and others have also joined, demonstrating the collective optimism of tech giants!

AI payment needs:

In 2025, AI agents (like robots that automatically buy data) will explode, and x402 will perfectly solve their payment needs.

Meme coin craze：

Now many merchants have not yet connected, so what can users buy? The simplest is to sell tokens!

Users pay USDC stablecoins, and the project party gives you tokens (actually air coins). This has become a new way of token issuance!

The overall process is as follows:

The first step is to trigger the x402 protocol.

The user clicks "Fetch Mint" on x402scan to initiate an HTTP request

The server returns an HTTP 402 status code ("payment required") with payment details (1 USDC, receiving address)

The user pays with MetaMask signature, and the x402 protocol sends a custom header (such as The second step is smart contract execution. The project party (such as $PING) deploys the contract on the Base chain and sets the rules: upon receiving 1 USDC, mint 5000 tokens to the user’s wallet. x402scan integrates these contracts. After the user pays, the contract is automatically executed and the tokens are distributed to the wallet. The third step is on-chain confirmation. Base Transaction verification is done on-chain (completed in seconds), and tokens are credited to your account, allowing you to trade on DEXs like Uniswap. x402scan records transactions in real time, providing transparency (similar to how Etherscan displays transfer records). Simply put, x402scan is the "Taobao page," x402 is the "Alipay," the smart contract is the "seller's shipping system," and the minted tokens are the "goods sold." $PING's first pre-sale, with 1 USDC minted for 5,000 tokens, saw its market capitalization surpass $30 million, an 18-fold increase! This wave of hype made x402 a hot topic.

In short, x402 is currently attracting everyone's attention as a token issuance method.

Six. How to participate in x402?

x402 is not only a protocol, but also an ecosystem. The core tools and projects are as follows:

1. x402scan:

A blockchain browser like Etherscan, it specifically records x402 payments and resources, such as who is using x402 and what they bought.

Core functions:

Check transactions: View payment records, USDC flows, and popular APIs.

Trial resources: Use 1 USDC to experience x402 payment, and you can also mint tokens (like $PING).

Ecosystem Overview: Lists popular projects, such as $PING.

2. Hot tokens (high risk, play with caution)

These tokens were issued during the x402 craze, but their fluctuations are like a roller coaster:

$PING: x402's leading meme coin, Base chain, 1 USDC Mint 5000 token, its market value once reached 30 million US dollars, an 18-fold increase.

$SANTA：AI agent related, Virtuals ecosystem, 1 USDC Mint, market value doubling.

$PAYAI：Solana cross-chain, AI payment narrative, community enthusiasm.

$GLORIA：x402 information AI, recently doubled in value. These tokens are mostly speculative and have weak fundamentals, like buying a lottery ticket—you could make a fortune, but you could also lose everything. You can find a resource (like $PING) on the x402scan website and click “Try Resources” → “Fetch Mint.” Pay 1 USDC, sign to confirm, and the token will be credited (like buying game skins). If you want to trade, you can sell on Uniswap (Base Chain). Be aware of the slippage (5-10%).

Other ways to play:

Developers: Want to add x402 payment to your website? Go to GitHub (coinbase/x402) to see the code, it can be done in just a few lines.

AI players: Use x402scan to test API payments and experience AI automatically buying data.

Follow hot spots: On x402scan, pay attention to new tokens (like $PONG), but don't chase high prices!

Seventh, what is the future of x402?

x402's potential lies in making AI and application payments as common as sending emails.

In the short term, it is still in the hype stage, and everyone is attracted by the wealth effect of the meme coin in the x402 ecosystem. However, with funding and market attention, the development of this sector will accelerate. In the long run, as more websites support x402, AI agents will use it to purchase data and computing power, and will become more widespread with the AI ​​boom. This protocol may become the Web3 payment standard, similar to HTTPS in Web2. If you believe in the prospects of stablecoin payments and the prospects of AI agents, then this sector is a must-watch!