What is x402? The HTTP-402 payments standard powering AI agents, explained

An API that fees for queries has at all times been a ache. Subscription ranges and month-to-month billing are eradicated as autonomous brokers carry out 1000’s of microtransactions per hour for brand new companies. x402 is Coinbase’s wager that the lacking piece is a cost primitive that connects on to HTTP.

The mechanism revives HTTP standing code 402 ‘Cost required’. When a shopper requests a useful resource, the server responds with 402 plus machine-readable cost phrases: quantity, asset, community, and recipient.

The client pays in USDC and tries once more with a cryptographic proof of cost in an HTTP header. The server verifies the settlement within the chain and serves the useful resource.

Coinbase launched x402 in Might 2025. By December, it had processed 75 million transactions value $24 million for paid APIs and AI brokers. V2 provides modularity: network-agnostic identifiers, pluggable enablers, pockets hooks, and a “Bazaar” discovery layer.

Cloudflare has introduced that it’ll combine x402 and co-launch the x402 Basis. Google Cloud’s Agent Funds Protocol makes use of x402 for on-chain settlement. CryptoSlate will combine it quickly. Solana and Base are the manufacturing networks, with Solana reportedly set to show round Base’s quantity by the tip of 2025.

Facilitators as cost gateways

The complexity lies within the ‘facilitator’, which screens blockchain networks, verifies funds, generates signed authorizations and supplies an HTTP interface in order that web sites can forestall nodes from operating.

Coinbase’s hosted facilitator gives free USDC funds on Base and Solana with high-throughput settlement. The protocol helps a number of impartial operators, however whether or not that portability survives if Coinbase’s enabler is free and deeply built-in is an open query.

Refunds work in another way than card networks. x402 has no reversal on the community degree. Sellers ship a compensating switch and replace the order standing. Fee capping is an software layer function: the 402 response encodes metering guidelines and facilitators implement per-wallet limits.

That makes x402 nearer to money than reversible card funds, a function for high-frequency API calls the place chargebacks can be disastrous, however a legal responsibility for client flows that want purchaser safety.

The gravity of the ecosystem

Cloudflare’s alignment signifies that x402 is infrastructure, not only a Coinbase undertaking.

By integrating x402 into Cloudflare’s edge compute and CDN stack, cost requests can match into on a regular basis internet workflows. The Basis’s framework for open governance and a number of implementers place the protocol as shared plumbing.

Google Cloud’s AP2 makes use of x402 for agent-to-agent success and connects it to hyperscaler AI stacks. Wallets resembling OneKey, Sahara and Transak have built-in x402 as a default primitive.

Case research present AEON dealing with AI-initiated funds to hundreds of thousands of retailers in Southeast Asia, Latin America and Africa.

The throughput is small, solely $24 million over seven months, however the route is essential. If autonomous brokers should pay per name as an alternative of monthly, x402 turns into a crucial plumbing job. The wager is that embedding funds in HTTP reduces friction sufficient to unlock new courses of transactions.

Threat and management

The largest danger is that Coinbase’s CDP service is probably the most mature.

Cloudflare and AP2 cut back focus on the protocol degree, however early site visitors flows via the Coinbase infrastructure. Coinbase shapes adoption by deciding which chains to prioritize and the way aggressively to subsidize charges.

The facilitator is free as of late, however that hardly ever lasts that lengthy as soon as the community results manifest.

Compliance is ingrained in facilitators. x402 itself is impartial, however hosted facilitators tie into KYT and sanctions screening, and political stress is targeted on facilitators.

Token confusion is endemic, as exchanges checklist speculative tokens branded ‘x402’, conflating the protocol with unrelated property. The group emphasizes that the protocol doesn’t have a local token, however the message competes with itemizing bulletins.

For Solana and Base, x402 is a wager that high-throughput, low-cost chains win the agent economic system. If the modal cost is $0.01 for an API name, the Ethereum mainnet is down and L2s with multi-cent charges are struggling.

Solana’s inversion of Base in quantity suggests sooner finality and decrease gasoline prices, giving it a structural benefit as brokers hammer APIs 1000’s of occasions per second.

The limitation is that x402 solves the coordination, not the liquidity. An agent paying for an API name wants USDC in a scorching pockets: holding keys, managing balances, dealing with danger.

It is manageable for builders, however for corporations deploying agent fleets, it turns into a compliance nightmare. The protocol makes funds manageable, however doesn’t assure that the encircling infrastructure is safe.

x402 will not be the primary try to switch funds by way of HTTP. What’s completely different is the mixture of stablecoins, low-cost blockchains and a reputable use case in autonomous brokers.

Whether or not this overcomes coordination issues and regulatory friction will decide whether or not x402 turns into primary plumbing or another experiment that by no means escapes the lab.