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URL Preflight Check
x402
URL Preflight Check is a paid API for AI agents from x240.jvnclk88.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-29).
Fetches a URL and returns its HTTP status, full redirect chain, key response headers, response time, robots.txt rules for the path, and sitemap location
Price / call$0.002
Success—
StatusUnknown
How this service works
URL preflight - status, redirect chain, key headers, response time, robots.txt rules for the path and sitemap location
Output
Returns a JSON object containing the final HTTP status code, the complete redirect chain (each hop's URL and status), key response headers (e.g. Content-Type, Cache-Control, X-Robots-Tag), the total response time in milliseconds, the robots.txt rules applicable to the requested path (allow/disallow), and the sitemap URL if discoverable.
Example use cases
Validate URLs before batch scrape
“I have a list of URLs I want to scrape — can you preflight check https://shop.example.com/products first to see if it's live, if there are any redirects, and if robots.txt will block us?”
Debug a broken link redirect chain
“This link https://old.example.com/blog/post-123 seems to be bouncing around — can you trace the full redirect chain for me so I can see where it ends up?”
SEO audit of robots and sitemap
“I'm auditing the site at https://www.mybrand.com/about — can you check whether that page is allowed by robots.txt and tell me where the sitemap is located?”
Technical details
Endpoint
POSThttps://x240.jvnclk88.workers.dev/url/check?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to verify a URL's reachability, understand its redirect behavior, check its robots.txt accessibility rules, or gather key HTTP headers before committing to a full scrape or crawl. It is ideal as a preflight step in any web automation pipeline to avoid wasting resources on dead links, redirect loops, or blocked pages.
Side effects
- Invalid or malformed URL returns a validation error
- Private or non-public URLs (e.g. localhost, internal IPs) are rejected
- DNS resolution failures result in a connection error response
- Very slow or timing-out URLs may return a timeout error
- Some servers block automated requests (403 Forbidden) which is reflected in the status
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| url | string | Public http or https URL to fetch |
Tags
x402
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