# URL Redirect Chain Tracer with Health Grading

> URL Redirect Chain Tracer with Health Grading is a paid API for AI agents from netintel-production-440c.up.railway.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-11).

Follows a URL through its full redirect chain (up to 20 hops), recording status codes, timing, headers, TLS status, and protocol downgrades per hop, then returns an overall redirect health grade (A–F).

## Facts

- Endpoint: GET https://netintel-production-440c.up.railway.app/redirect/trace?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/netintel-production-440c-up-railway-app-c8f075f5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fsqM4mzxIUqXuSS-zJK_e

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 netintel-production-440c-up-railway-app-c8f075f5
```

Example prompt: Can you trace all the redirects for http://bit.ly/3xampleLink and tell me the full redirect chain, whether it ever downgrades from HTTPS to HTTP, and what overall health grade it gets?

## When to prefer this

Use this endpoint when you need to audit or debug the full redirect path of a URL, detect redirect loops, check for HTTP-to-HTTPS protocol downgrades, measure per-hop latency, or get an at-a-glance health grade for a URL's redirect chain. Prefer it over a simple HEAD request when chain depth, TLS integrity, or redirect health scoring matters.

## Known failure modes

- Invalid or malformed URL input — returns an error indicating bad input
- Loop detected after exhausting max hops — loop_detected flag set to true, chain truncated
- Target URL is unreachable or times out — connection error returned
- max_hops exceeds 20 — capped or rejected with validation error
- Non-HTTP/HTTPS scheme provided — unsupported protocol error

## How this service works

Follows a URL through its full redirect chain (up to 20 hops), recording status codes, timing, headers, TLS status, and protocol downgrades per hop, then returns an overall redirect health grade (A–F).

## Output

Returns the full redirect chain as an array of hops (each with URL, status code, timing, TLS status, headers), plus: final URL, final status code, total hop count, total timing in ms, loop detection boolean, protocol downgrade boolean, a list of flags and deductions, a numeric health score, and an overall letter grade (A–F) summarizing redirect health.

## Example request

```json
{
 "input": {
  "type": "http",
  "method": "GET",
  "queryParams": {
   "url": "http://example.com",
   "max_hops": 10
  }
 }
}
```

## 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",
       "description": "URL to trace redirects for (e.g. http://google.com)"
      },
      "max_hops": {
       "type": "number",
       "description": "Maximum redirect hops to follow (default: 10, max: 20)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "chain": {
       "type": "array"
      },
      "flags": {
       "type": "array"
      },
      "grade": {
       "type": "string"
      },
      "score": {
       "type": "number"
      },
      "final_url": {
       "type": "string"
      },
      "deductions": {
       "type": "array"
      },
      "total_hops": {
       "type": "number"
      },
      "loop_detected": {
       "type": "boolean"
      },
      "total_timing_ms": {
       "type": "number"
      },
      "final_status_code": {
       "type": "number"
      },
      "protocol_downgrade": {
       "type": "boolean"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "chain": [
   {
    "hop": 0,
    "tls": false,
    "url": "http://example.com/",
    "headers": {
     "server": "nginx",
     "location": "https://example.com/"
    },
    "location": "https://example.com/",
    "timing_ms": 85,
    "status_code": 301
   },
   {
    "hop": 1,
    "tls": true,
    "url": "https://example.com/",
    "headers": {
     "server": "nginx",
     "content-type": "text/html"
    },
    "location": null,
    "timing_ms": 42,
    "status_code": 200
   }
  ],
  "flags": [
   "http_entry_point"
  ],
  "grade": "A",
  "score": 95,
  "final_url": "https://example.com/",
  "deductions": [
   {
    "points": -5,
    "reason": "http_entry_point"
   }
  ],
  "total_hops": 1,
  "loop_detected": false,
  "total_timing_ms": 127,
  "final_status_code": 200,
  "protocol_downgrade": false
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/netintel-production-440c-up-railway-app-c8f075f5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from netintel-production-440c.up.railway.app](https://www.zero.xyz/host/netintel-production-440c.up.railway.app/llms.txt)