# 402Signal Route Lookup

> 402Signal Route Lookup is a paid API for AI agents from 402signal.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).

Returns a live, probed x402 endpoint URL (or an honest miss) for a given URL or need, confirming whether the endpoint is currently alive and returning a proper 402 challenge.

## Facts

- Endpoint: POST https://402signal.com/route
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/402signal-route-lookup-d133a35c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_DFIn2qcKjk3OFYSp9YDLa

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability 402signal-route-lookup-d133a35c -d '<json body>'
```

Example prompt: Is there a live x402 endpoint available for balance checking? I want a URL that's currently up and returning a real 402 payment challenge — check 402Signal and tell me what you find.

## When to prefer this

Use 402Signal when your agent needs to discover or verify that a specific x402-gated endpoint is currently alive and serving a proper 402 payment challenge, especially before spending money on a call. It is the right choice over static directories when freshness and liveness confirmation matter, as it probes endpoints in real time and reports actual HTTP status, latency, and challenge presence. Prefer it when you have a candidate URL or a description of what you need and want a fail-closed, honest answer about reachability.

## Known failure modes

- No matching live endpoint found — returns honest miss with live: false and no URL
- Input URL or need is malformed or missing — likely returns a 400 or validation error
- The probed endpoint is temporarily down — returns live: false with last known probe data
- Payment of $0.01 USDC fails or is not authorized — request is rejected (fail-closed behavior)
- Network timeout reaching the target endpoint — latency_ms reflects timeout, live: false

## How this service works

402Signal checks the endpoint, price and recipient before your agent pays, on x402 and MPP, and returns a signed record verifiable offline. $0.003 on Base, Solana, and Algorand only when a qualifying live offer is found; a miss is free. Seller payment is separate. Your agent keeps the wallet. Evidence enters the PQ Trust log on Algorand MainNet. require_route_binding=true adds a signed v4 receipt for buyer-side comparison before signing. Guide: https://402signal.com/developers#route-binding

## Output

A JSON object containing: the resolved URL, a live boolean, a health object with liveness status, HTTP status code (typically 402), last probe timestamp, latency in milliseconds, and whether a 402 challenge header is present. On an honest miss, the live field is false with no URL.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string"
  },
  "need": {
   "type": "string"
  },
  "require_transparency": {
   "type": "boolean",
   "description": "Require a durable leaf and signed checkpoint receipt on HTTP 200. Default false; require_route_binding=true also requires transparency. Receipt failure after settlement remains billed. Private replay records support bounded recovery of the original response; they are not long-term evidence storage. Keep your own copy outside public logs."
  },
  "require_route_binding": {
   "type": "boolean",
   "description": "Opt in to a signed v4 route binding; implies require_transparency even if false. Default false; ordinary requests keep v3. A ranked winner that cannot bind may fall through to the next already-probed selectable bindable candidate; 503 route_binding_unavailable only when none remain. wrapExactAuthorize reports state=binding_unavailable with keep_calling_route true; policy working, not a crash. Buyer verifies raw response JSON with a pinned log key and compares the current seller request and challenge before signing. Expiry or changed terms do not undo a settled checking fee. Guide: https://402signal.com/developers#route-binding"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "url": "https://example.com/x402/balance",
  "live": true,
  "health": {
   "live": true,
   "status": 402,
   "last_probe": "2026-08-29T22:00:00-04:00",
   "latency_ms": 87,
   "has_402_challenge": true
  },
  "status": 402,
  "probed_at": "2026-08-29T22:00:00-04:00",
  "latency_ms": 87,
  "has_402_challenge": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/402signal-route-lookup-d133a35c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 402signal.com](https://www.zero.xyz/host/402signal.com/llms.txt)