# tempo.halowerk.com – Font Render-Blocking Resources Check

> tempo.halowerk.com – Font Render-Blocking Resources Check is a paid API for AI agents from tempo.halowerk.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Checks the number of render-blocking font resources on a given web page or font asset URL.

## Facts

- Endpoint: POST https://tempo.halowerk.com/v1/pruef/tempo/blockierer/schrift
- 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/tempo-halowerk-com-font-render-blocking-resources-check-fbd1a2df
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_EH5UZhOkEhg2WFN1EPeIi

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 tempo-halowerk-com-font-render-blocking-resources-check-fbd1a2df -d '<json body>'
```

Example prompt: Check how many render-blocking font resources are on https://www.example.com and tell me if any fonts are blocking the page from loading.

## When to prefer this

Use this endpoint when you specifically need to audit render-blocking font resources on a webpage, as part of web performance analysis or Core Web Vitals optimization workflows. Prefer this over generic page-speed tools when you need a programmatic, per-check result that can be integrated into CI/CD pipelines or automated monitoring. Especially useful when diagnosing slow above-the-fold render times suspected to be caused by font loading.

## Known failure modes

- URL is not publicly accessible — returns an error or unreachable status
- URL is too long or malformed — rejected by schema validation (maxLength 2048)
- CSS selector matches no element or multiple elements — first match used or error returned
- Target page has no font resources — count returns zero
- Timeout fetching the target URL — may return a timeout or empty result
- Non-HTTP(S) URL provided — rejected by input validation

## How this service works

Prüft am Objekt schrift den Befund Zahl renderblockierender Ressourcen.

## Output

Returns a structured audit finding (Befund) indicating the count of render-blocking font resources detected on the specified page or font object, enabling developers to identify performance bottlenecks caused by blocking font loads.

## 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/tempo-halowerk-com-font-render-blocking-resources-check-fbd1a2df/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from tempo.halowerk.com](https://www.zero.xyz/host/tempo.halowerk.com/llms.txt)