# Mekler AI URL Reachability Check

> Mekler AI URL Reachability Check is a paid API for AI agents from api.mekler.ai, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-28).

Inspects a public URL for HTTP status, redirect chain, content type, and reported size using HEAD with bounded GET fallback, without downloading the full resource.

## Facts

- Endpoint: POST https://api.mekler.ai/v1/web/urls/check-reachability?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-28
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/mekler-ai-url-reachability-check-a59ee94b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_m16GeXwDFZ9WEW7P8QhIm

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 mekler-ai-url-reachability-check-a59ee94b -d '<json body>'
```

Example prompt: Can you check if this URL is reachable and tell me its HTTP status, any redirects, and the content type — without actually downloading the file? https://example.com/report.pdf

## When to prefer this

Choose this endpoint when you need lightweight, non-destructive HTTP diagnostics on a URL — especially to confirm reachability, trace redirects, or get content-type and size metadata before committing to a full download. Prefer it over general web scrapers when you do not need page content, and over uptime monitors when you need a one-shot diagnostic rather than continuous polling. Best suited for pre-flight checks in data pipelines, link validation in user-submitted content, or debugging redirect chains.

## Known failure modes

- URL points to a private/non-public IP address — blocked by DNS pinning checks
- Redirect chain exceeds five hops — returns partial chain with error
- URL scheme is not HTTP or HTTPS — rejected at input validation
- Server does not respond within timeout — returns unreachable outcome
- URL is syntactically invalid or exceeds 2048 characters — validation error
- Server returns an HTTP error (4xx/5xx) — reported as a completed diagnostic, not a service failure

## How this service works

Inspect a public URL for HTTP status, redirect chain, content type and reported size before downloading it. Uses HEAD with bounded GET fallback, DNS-pinned public-address checks and up to five redirects. Reports server-declared sizes separately from observed sample bytes. No full download, content safety verdict or uptime guarantee.

## Output

Returns a JSON object with the outcome (reachable/unreachable), final URL after redirects, full redirect chain with per-hop method and status, HTTP status code, content type, server-declared size in bytes, observed sample bytes, size basis (server_header vs observed), whether the sample was truncated, timestamp of observation, and a list of diagnostic limitations.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "maxLength": 2048
  },
  "request_id": {
   "type": "string",
   "pattern": "^[A-Za-z0-9_-]{16,64}$"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "status": "ok",
  "outcome": "reachable",
  "final_url": "https://mekler.ai/",
  "redirects": [
   {
    "url": "https://mekler.ai/",
    "method": "HEAD",
    "status": 200
   }
  ],
  "size_basis": "server_header",
  "http_status": 200,
  "limitations": [
   "HEAD metadata and range samples do not verify full content or total download size.",
   "Only public HTTP(S) ports80/443, up tofive redirects; robots restrictions apply.",
   "An observed HTTP error or redirect loop is a completed diagnostic, not guaranteed future availability."
  ],
  "observed_at": "2026-10-18T00:00:00Z",
  "content_type": "text/html",
  "requested_url": "https://mekler.ai/",
  "sample_truncated": false,
  "reported_size_bytes": 1024,
  "sample_bytes_observed": 0
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/mekler-ai-url-reachability-check-a59ee94b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.mekler.ai](https://www.zero.xyz/host/api.mekler.ai/llms.txt)