What Is x402 Used For?
x402 is used to charge for individual web requests. Common uses include pay-per-call APIs, paid MCP tools for AI agents, metered data and search, content access for AI crawlers, compute and inference billed per use, and agents paying other agents for tasks. Payments are usually small amounts of USDC, settled before the response is returned.
Pay-per-call APIs
The most common use is charging for API requests. Instead of requiring signup, a card, and a subscription, the API returns 402 with a price, and any client that pays gets the response. This suits occasional users, developers testing an API, and AI agents that discover services at runtime.
Paid MCP tools
Model Context Protocol servers expose tools to AI clients. With x402, each tool call can carry a price, so a provider can sell lookups, computations, or actions to any agent that connects. Cloudflare's Agents SDK documents this as paid tools.
Data and search
Data providers sell records, market data, search results, or enrichment per request. Per-call pricing matches value to use, and agents can buy exactly the data a task needs without a plan.
Content and AI crawler access
Publishers can charge AI crawlers and agents for access to content instead of blocking them or giving it away. HTTP 402 based schemes let a site quote a price for a page or dataset and serve it once paid.
Compute and inference
Inference endpoints, rendering services, and other compute can charge per job or per unit of usage. The up-to scheme lets a client authorise a maximum and pay actual usage, which suits variable workloads.
Agent-to-agent services
An agent that specialises in a task, such as translation or analysis, can sell its service to other agents via x402. The buying agent pays per request; the selling agent verifies payment before doing the work.
Micro-subscriptions and prepaid access
x402 V2 added subscription and prepaid flows and sessions, so services can offer short-term access or bundles while keeping the same payment protocol.
Anti-abuse
Charging even a tiny amount per request can deter spam and scraping, since abuse becomes costly. Providers can price high-cost endpoints higher than cheap ones.
What x402 is not for
x402 is not a shopping cart or checkout protocol for physical goods, and not an identity protocol. Commerce protocols such as ACP and UCP handle retail checkout, and identity protocols such as x401 handle proof of who stands behind an agent.
Why stablecoins
Most x402 payments use USDC because it holds a dollar value, settles fast, and costs little to move on networks such as Base. Card rails have minimum amounts that make sub-dollar charges uneconomic.
Who uses x402
API providers, data companies, publishers, infrastructure platforms, and agent developers use x402. It is backed by the x402 Foundation, whose members include payment networks, cloud providers, and crypto companies.
Using x402 safely as a payer
Agents paying x402 resources should check prices against budgets before paying, use bounded wallets or session keys, restrict which services they pay, and log every payment. A valid 402 response is a price quote, not an obligation to pay.
Example: a research agent
A research agent compiling a market report pays a news API per article, a financial data API per query, and a specialised analysis agent per task, all through x402. Each payment is small and logged. The operator sets a total budget for the report, and the agent stops paying when the budget is reached.
Example: a publisher
A publisher allows human readers free access but charges AI agents and crawlers a small amount per article through HTTP 402. Agents that pay receive the full text; those that do not receive a payment requirement instead of content. The publisher earns from AI usage without negotiating individual licensing deals.
Example: an API startup
A startup launches a new API with no signup flow at all. Any developer or agent can call it and pay per request in USDC. Early usage data shows which endpoints have demand, and the startup later adds subscription plans for heavy users while keeping pay-per-call for everyone else.
Example: compute marketplaces
Compute providers can expose GPU jobs or rendering tasks behind x402, quoting a maximum price for a job and charging actual usage with the up-to scheme. Agents submit jobs and pay without accounts, making it easier to use multiple providers and route work to whichever is cheapest or fastest.
Measuring x402 adoption
Public explorers and dashboards track x402 payment counts and volumes onchain. When reading these figures, distinguish real service payments from test traffic and token-related activity, which can inflate headline numbers during periods of speculation.
Getting started with Is x402 Used For
Providers can start by putting one endpoint behind x402 at a modest price and watching who pays. Agent builders can start by funding a test wallet on Base Sepolia and calling a paid endpoint with an x402 client, with a strict budget in place from the first request.
Frequently asked questions
- What can you do with x402?
- You can charge for any web request: API calls, MCP tool calls, data and search results, content for AI crawlers, compute jobs, and services one agent sells to another. Clients pay small amounts, usually USDC, and receive the response once payment is verified, with no accounts or subscriptions.
- Is x402 only for AI agents?
- No. Any HTTP client can pay x402 resources, including scripts, apps, and people using compatible wallets. AI agents are a major use case because they cannot easily sign up for accounts or enter cards, and per-request payment fits how they discover and use services.
- What currency does x402 use?
- Most x402 payments use USDC, a dollar stablecoin, on networks such as Base or Solana. The protocol supports other tokens that meet its authorisation requirements, and V2 added hooks for traditional rails. There is no x402 token; the protocol settles in existing assets.