A payment-enabled web request
The x402 protocol adds a payment request to an HTTP interaction so a user or software agent can pay before receiving a resource.
The request can specify the token, amount, wallet destination and network, allowing settlement without a traditional card or subscription flow.
In a typical exchange, a server can respond that payment is required and include machine-readable instructions for completing it. After payment is verified, the server can deliver the requested content or service, letting the payment step fit into an ordinary web request.
Why agents need it
AI agents can call APIs, access data and purchase services, but traditional payment systems often require a human account holder.
Stablecoin micropayments let an agent pay per request while keeping the transaction programmable and machine-readable.
An agent can be authorized with a spending limit and a set of permitted services, then make small payments without asking a person to approve every request. Strong safeguards are still needed so a compromised agent cannot spend beyond its intended budget.
Use cases
Possible applications include pay-per-call APIs, metered content, compute access, data feeds and machine-to-machine marketplaces.
The same mechanism can also support human users who prefer one-time payments over account creation or recurring subscriptions.
A developer might charge for a single data lookup, an image-generation request or a short period of compute rather than require an account and monthly plan. These models are most useful when payment costs and confirmation delays remain small relative to the value delivered.
Open questions
Adoption depends on wallet security, identity, refunds, network fees, fraud controls and merchant integration.
A web-native payment standard is useful only when developers can implement it reliably and users understand what they are authorizing.
Systems must handle failed requests, duplicate payments, refunds and disputes in ways users can understand. Merchants also need to verify settlement safely and account for volatility, compliance and transaction fees before relying on the protocol for production revenue.