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SALT19 URL HTTP Preflight Check
x402
SALT19 URL HTTP Preflight Check is a paid API for AI agents from salt19-agent-utility-grid.salt19-llc.workers.dev, paid per call via x402, $0.03/call, status unknown (last checked 2026-09-14).
Performs an HTTP preflight check on a URL, returning redirect chain, latency, content type, and security header analysis
Price / call$0.03
Success—
StatusUnknown
How this service works
Machine-discoverable, x402-paid technical decision utilities for autonomous agents.
Output
A JSON object containing the HTTP status code of the final response, the resolved final URL after any redirects, the number of redirects followed, round-trip latency in milliseconds, the Content-Type of the response, and a breakdown of key security headers (X-Content-Type-Options, Content-Security-Policy, Strict-Transport-Security) as boolean presence flags.
Example use cases
Verify webhook before registration
“Before I register this webhook URL https://hooks.myapp.com/events, can you preflight it to confirm it responds with a 200, check its final destination after any redirects, and tell me if it has strict transport security set?”
Security header audit for landing page
“Can you check https://www.mycompany.com and tell me which security headers it's missing — specifically whether it has Content-Security-Policy, HSTS, and X-Content-Type-Options configured?”
Latency check before link goes live
“I'm about to publish this URL https://cdn.partner.io/assets/report.pdf in a newsletter — can you preflight it to make sure it's live, see how fast it responds, and confirm what content type it returns?”
Technical details
Endpoint
POSThttps://salt19-agent-utility-grid.salt19-llc.workers.dev/v1/url-http-preflightWhen to prefer
Use this endpoint when an agent needs to verify a URL is live, resolve its final destination after redirects, measure response latency, or check for security header presence — all before committing to a heavier fetch or downstream action. It is particularly useful for webhook validation, pre-publish link checking, and lightweight security audits where a full page crawl or content extraction is unnecessary and wasteful.
Side effects
- URL is unreachable or times out — may return a non-200 status or error object
- Malformed or non-URI input rejected at schema validation
- URL resolves to a redirect loop — redirect count may exceed limit
- Target server blocks automated requests, returning 403 or 429
- TLS/SSL errors on HTTPS URLs may cause connection failure
- DNS resolution failure for the given hostname
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| url | string |
Output
Schema · Response
{
"type": "json",
"example": {
"status": 200,
"final_url": "https://example.com/",
"redirects": 0,
"latency_ms": 110,
"content_type": "text/html",
"security_headers": {
"x_content_type_options": true,
"content_security_policy": false,
"strict_transport_security": true
}
}
}Tags
x402
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