01What is x402?
x402 is an open payment standard that puts payment inside the HTTP request itself. In the 1990s the web's architects reserved status code 402, "Payment Required," for native web payments, but it sat unused for thirty years because card fees made small payments uneconomic and no instant, low-cost settlement layer existed. Stablecoins and sub-cent layer 2 fees removed both barriers.
With x402, an agent pays for an API call, data feed or page with no account, subscription or API key. The protocol is open source under the MIT license, charges no protocol fees and is backwards-compatible through standard HTTP headers.
02How does an x402 payment work?
The protocol adds two headers to HTTP: the server states the price, token, network and recipient wallet, and the client returns a signed payment proof. One paid call runs in five steps:
- Request: the agent sends an HTTP GET or POST to the endpoint.
- Quote: the server returns HTTP 402 with the amount, token and address.
- Sign: the agent signs an EIP-3009 USDC authorization from its wallet.
- Settle: a facilitator verifies the signature and amount and settles onchain.
- Deliver: the server confirms payment and returns the resource.
The full flow takes about two seconds and costs about $0.0001 in USDC on Base.
03Who built x402?
Coinbase built x402 and launched it in May 2025. Erik Reppel, Head of Engineering at the Coinbase Developer Platform, designed it to replace the API keys, subscriptions and batch billing that API providers used to charge agents. Coinbase also operates the CDP facilitator, runs Base as the primary settlement chain and launched Agentic Wallets.
Cloudflare co-founded the x402 Foundation with Coinbase in September 2025 so the standard would not be seen as Coinbase-proprietary. The Foundation moved under the Linux Foundation and began operating on July 14, 2026 with 40 members, including Visa, Mastercard, American Express, AWS, Google and Stripe. Google integrated x402 into its Agent Payments Protocol, Stripe launched x402-based USDC payments on Base in February 2026, and Visa built x402 interoperability into its Trusted Agent Protocol.
04How much volume does x402 process?
x402 processed about 165M transactions and $46.5M in cumulative volume in its first ten months, with about 3.6M transactions and $3.5M in the 30 days to March 17, 2026. Daily volume peaked at $3.01M on November 3, 2025 and was $94.5K on March 9, 2026, down 96.9%. Weekly volume fell from $5.3M in November 2025 to under $220K in February 2026.
Visa's Cuy Sheffield said roughly 95% of 2025 x402 volume was tied to memecoins. Galaxy Research data shows the share of gamed or wash-traded transactions fell below 50% in early December 2025 and kept falling.
x402 daily volume to March 9, 2026
Daily x402 volume peaked in November 2025 and has since fallen by almost 97%.
- Peak day
- $3.01M November 3, 2025
- Daily volume
- $94.5K March 9, 2026
- Change from peak
- -96.9% $2.91M decline
05Who are the main facilitators?
Facilitators verify payments and settle them onchain so API providers need no blockchain infrastructure. All-time figures from x402scan as of March 17, 2026:
- Coinbase: 78.3M transactions, $27.3M, 58.7% of dollar volume, about $0.35 per transaction.
- PayAI: 34.5M transactions, $4.8M, 10.4% share.
- Dexter: 26.4M transactions, $4.7M, 10.2% share; its zero-fee model is compressing facilitator margins.
- Virtuals Protocol: 1.7M transactions, $3.6M, 7.8% share, but $2.3M of the last 30 days' $3.5M (65%).
- Daydreams: 11.8M transactions, $2.8M, 5.9% share.
Coinbase leads on cumulative dollar volume, but Dexter overtook it in daily transaction share (about 35% against 25%).
06How does x402 compare with card networks?
Card checkout costs 2.9% plus $0.30 per transaction and requires accounts, KYC and batch settlement, which rules out a $0.001 API call. An x402 payment settles in about two seconds for about $0.0001 on Base.
On scale, x402 is far behind. Visa processes $14T a year, and x402's entire 10-month volume is less than one Visa day: lifetime volume of $45.68M fills 0.0039% of one month of Visa payments.
07Is there an x402 token?
No. x402 has no native token and charges no protocol fees, so value accrues to the businesses around it: settlement chains, stablecoin issuers, facilitators, agent frameworks and identity layers. Coinbase may be the largest single beneficiary through Base sequencer fees, CDP facilitator fees and its USDC reserve yield arrangement with Circle, though x402 is not yet a disclosed line in its earnings.
Tokens with a genuine x402 connection totaled under $700M in aggregate market cap as of March 2026. The CoinGecko x402 category showed about $6.7B, inflated by tokens whose main value drivers are elsewhere.
08What are the main risks?
- Volume decline from peak: weekly volume fell from $5.3M to under $220K as memecoin activity deflated.
- Competing standards: h402 (BitGPT) and EVMAuth (Radius) offer alternatives, and the Machine Payments Protocol, launched with Tempo's mainnet on March 18, 2026 and co-authored with Stripe, competes for the same agent payment flows.
- Facilitator commoditization: Dexter's zero-fee model has compressed margins; a hackathon submission ran a facilitator for $5 a month.
- No formal security audit: Trail of Bits, OpenZeppelin and Certik had published none as of March 2026; replay attack vectors and CDP single-point-of-failure risks are unaddressed at the protocol level.
- MEV exposure: high-frequency agent payments on Base or Solana are open to sandwich attacks and front-running of payment proofs.
- Regulation: liability, consumer protection and money transmission rules for autonomous agent transactions are unresolved.
09What should we watch next?
- Cloudflare pay-per-crawl: general availability would make AI web crawls x402 payments.
- Named enterprise deployment: a major SaaS provider running an x402 server, which Visa's Cuy Sheffield predicted for 2026.
- Google A2A enterprise rollout: bringing x402 into corporate agent workflows through the Agent Payments Protocol.
- Coinbase disclosure: x402 revenue reported as a line item in Coinbase earnings.
- Frontier AI models with USDC wallets: ChatGPT, Claude or Gemini transacting natively in USDC.
- Identity and commerce standards: adoption of ERC-8004 and of ERC-8183 by third-party commerce protocols.