# x402 Preflight > x402 Preflight is a paid API for AI agents from f0r6bcvc1s410hk1.68r.lambda-web.us-east-1.on.aws, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-29). Probes an x402 paywall endpoint before payment to return a trust verdict (ok/caution/avoid) with uptime, buyer count, price comparison, and payment validity checks. ## Facts - Endpoint: GET https://f0r6bcvc1s410hk1.68r.lambda-web.us-east-1.on.aws/v1/preflight?utm_source=zero.xyz - Price: $0.002/call - Payment: x402 - Status: unknown - Last checked: 2026-10-29 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/x402-preflight-5543495b - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wm5R8x3RgzJ2pJ1MNuo4I 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 x402-preflight-5543495b ``` Example prompt: Before I pay that x402 search endpoint at https://api.example.com/v1/search, check whether it's trustworthy — probe it live, see how many buyers have paid it in the last 30 days, and tell me if there are cheaper alternatives I should use instead. ## When to prefer this Use this endpoint when an AI agent is about to call an x402-gated API and needs to verify payment safety, check real-world usage evidence, compare price against alternatives, or enforce a maximum price budget before committing any funds. It is the right choice whenever you want a second opinion on an unknown x402 seller, need uptime data for reliability decisions, or want to discover cheaper equivalent services before paying. ## Known failure modes - Endpoint URL is unreachable or returns non-402 status — live probe fails with no payment info returned - Endpoint not listed on Bazaar — bazaar field will be null or show listed:false, limiting social proof data - No monitoring history available — history field returns null if the endpoint has never been monitored - Invalid or missing URL query parameter — API returns a validation error - Endpoint returns malformed x402 payment headers — preflight flags it as avoid with a reason explaining the parsing failure ## How this service works Check an x402 seller before you pay it. Probes the endpoint now, checks that its payment can actually succeed (token EIP-712 domain, payTo), and adds its 30-day uptime from our monitor of paid Bazaar listings, how many distinct buyers paid it, and how its price compares with similar listings, with cheaper well-used alternatives. Returns a verdict (ok, caution, avoid) with the reasons. ## Output A JSON object containing: a live probe result (status, latency, payTo address, price, networks, x402 protocol version), a verdict of 'ok', 'caution', or 'avoid' with a list of reasons, Bazaar listing data (distinct payers and calls in 30 days), 30-day uptime history (probes, uptime ratio, median latency, last failure, price changes), and market context (median price of similar listings and cheaper well-used alternatives). ## Request schema (JSON Schema) ```json { "type": "object", "$schema": "https://json-schema.org/draft/2020-12/schema", "required": [ "input" ], "properties": { "input": { "type": "object", "required": [ "type", "method" ], "properties": { "type": { "type": "string", "const": "http" }, "method": { "enum": [ "GET" ], "type": "string" }, "queryParams": { "type": "object", "required": [ "url" ], "properties": { "url": { "type": "string", "maxLength": 2048, "description": "https URL of the x402 endpoint you are about to pay" }, "method": { "enum": [ "GET", "POST" ], "type": "string", "description": "method you will call it with (default GET)" }, "max_price_usd": { "type": "number", "description": "the most you are willing to pay per call; a higher price gives the verdict avoid" } } } }, "additionalProperties": false }, "output": { "type": "object", "required": [ "type" ], "properties": { "type": { "type": "string" }, "example": { "type": "object", "required": [ "url", "verdict", "reasons" ], "properties": { "now": { "type": "object", "description": "the live probe: method, status, latency, protocol version, price, networks, payTo" }, "url": { "type": "string" }, "bazaar": { "type": "object", "description": "the CDP Bazaar listing: distinct payers and calls in 30 days" }, "market": { "type": "object", "description": "median price of similar listings and cheaper alternatives with payers and uptime" }, "history": { "type": "object", "description": "our monitor's 30-day record: probes, uptime (0-1), median latency, last failure, price changes; null when not monitored" }, "reasons": { "type": "array", "description": "why the verdict is not ok; empty when it is" }, "verdict": { "enum": [ "ok", "caution", "avoid" ], "type": "string" } } } } } } } ``` ## Response schema (JSON Schema) ```json { "type": "json", "example": { "now": { "ms": 180, "method": "GET", "pay_to": "0x...", "status": 402, "networks": [ "eip155:8453" ], "price_usd": 0.01, "x402_version": 2 }, "url": "https://api.example/v1/search", "bazaar": { "listed": true, "calls_30d": 3, "payers_30d": 1, "last_called_at": "2026-10-20T08:00:00Z" }, "market": { "query": "Web search for agents", "alternatives": [ { "resource": "https://other.example/search", "price_usd": 0.002, "payers_30d": 40, "uptime_30d": 1 } ], "median_price_usd": 0.005, "similar_listings": 20 }, "history": { "probes": 120, "uptime": 0.99, "median_ms": 210, "last_ok_at": "2026-10-25T00:00:00Z", "last_failure": null, "price_changes": [], "monitored_since": "2026-10-01T00:00:00Z" }, "reasons": [ "Only 1 distinct buyer paid it in the last 30 days." ], "verdict": "caution" } } ``` ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-preflight-5543495b/health.json - [Zero catalog index](https://www.zero.xyz/llms.txt) - [Other services from f0r6bcvc1s410hk1.68r.lambda-web.us-east-1.on.aws](https://www.zero.xyz/host/f0r6bcvc1s410hk1.68r.lambda-web.us-east-1.on.aws/llms.txt)