Find a paid API that works right now.

402Signal checks x402 services immediately before an agent uses them. It keeps catalog claims separate from what the endpoint actually returns, then gives the agent a route or a clear miss.

Base · Solana · Algorand

Browse catalog Developer docs

402Signal recommends the route. Your agent keeps the wallet.

DISCOVERY

What sellers say is available

Catalogs / Directories / Seller metadata

402SIGNAL

Check it now

Valid x402? / Payment terms? / Invocation info? / Fresh observation?

YOUR AGENT

Decide whether to spend

Own wallet / Sign / Pay seller / Call API

If the check does not pass, 402Signal returns a miss instead of quietly substituting an unverified service.

The live routing check costs $0.01 USDC. 402Signal does not hold your keys or pay the selected seller for you.

Browse the catalog

See which x402 services are listed across the discovery sources 402Signal queries. Catalog listings are candidates, not live verification.

Browse catalog

Use 402Signal in an agent

Call 402Signal through HTTP or MCP when your agent needs a fresh check before spending.

Developer docs