# Crawlspur Canonical Indexability Checker

> Crawlspur Canonical Indexability Checker is a paid API for AI agents from crawlspur.halowerk.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Checks the technical indexability status of the canonical element on a given URL or web object.

## Facts

- Endpoint: POST https://crawlspur.halowerk.com/v1/pruef/crawlspur/indexierbar/canonical
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/crawlspur-canonical-indexability-checker-8a8306e2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FjNjYRfswy9-YLZf_dBf8

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 crawlspur-canonical-indexability-checker-8a8306e2 -d '<json body>'
```

Example prompt: Can you check whether the canonical tag on https://example.com/my-page is technically indexable and flag any issues that might prevent it from being crawled?

## When to prefer this

Use this endpoint when you specifically need to audit the canonical tag of a webpage for technical indexability issues, especially as part of an automated SEO crawl pipeline or site health check. Prefer this over generic page crawlers when the specific concern is whether the canonical element is correctly configured to allow search engine indexing.

## Known failure modes

- Invalid or unreachable URL returns an error or empty finding
- Malformed CSS selector results in no object match or first-match fallback
- Non-public or firewalled URLs may fail to fetch
- URL exceeds 2048 character limit causes validation error
- User agent string not matching required pattern causes rejection

## How this service works

Prüft am Objekt canonical den Befund technische Indexierbarkeit.

## Output

Returns a structured finding ('Befund') describing whether the canonical element on the specified URL or web object is technically indexable, including any SEO-relevant issues detected with the canonical tag configuration.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "ziel": {
   "oneOf": [
    {
     "type": "string",
     "maxLength": 2048,
     "minLength": 1,
     "description": "Öffentliche HTTP(S)-Adresse; bei DNS-Befunden Domain oder öffentliche IP."
    },
    {
     "type": "object",
     "required": [
      "adresse"
     ],
     "properties": {
      "adresse": {
       "type": "string",
       "maxLength": 2048,
       "minLength": 1
      },
      "selektor": {
       "type": "string",
       "maxLength": 240,
       "minLength": 1,
       "description": "CSS-Selektor: genau ein Objekt, sonst erster Treffer des Objektfilters."
      },
      "vergleich": {
       "type": "string",
       "maxLength": 2048,
       "description": "Öffentliche Vergleichsadresse für Link-, Sitemap- oder Sprachbefunde."
      },
      "user_agent": {
       "type": "string",
       "pattern": "^[A-Za-z0-9_-]{1,80}$"
      },
      "dkim_selektor": {
       "type": "string",
       "pattern": "^[A-Za-z0-9_-]{1,63}$"
      }
     },
     "additionalProperties": false
    }
   ]
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/crawlspur-canonical-indexability-checker-8a8306e2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from crawlspur.halowerk.com](https://www.zero.xyz/host/crawlspur.halowerk.com/llms.txt)