# Halowerk Tempo – Stylesheet Render-Blocking Resources Check

> Halowerk Tempo – Stylesheet 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 a public URL and counts the number of render-blocking stylesheet resources found on the page.

## Facts

- Endpoint: POST https://tempo.halowerk.com/v1/pruef/tempo/blockierer/stylesheet
- 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/halowerk-tempo-stylesheet-render-blocking-resources-check-177a3ae7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_gBgAwC4LkPSiDQFFURK7T

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 halowerk-tempo-stylesheet-render-blocking-resources-check-177a3ae7 -d '<json body>'
```

Example prompt: Can you check how many render-blocking stylesheet resources are on https://example.com and tell me the count?

## When to prefer this

Use this endpoint when you specifically need to count render-blocking stylesheet resources on a webpage as part of a performance audit or monitoring workflow. It is distinct from sibling endpoints that check iframes or fonts for render-blocking issues, or stylesheets for other metrics like DNS resolution time or connection setup time.

## Known failure modes

- Invalid or non-public URL returns a validation error
- URL is unreachable or returns a non-200 status, resulting in a connection error
- CSS selector matches no elements or multiple elements (first match used)
- Target site blocks automated requests, leading to incomplete or failed analysis
- Timeout if the target page loads too slowly

## How this service works

Prüft am Objekt stylesheet den Befund Zahl renderblockierender Ressourcen.

## Output

Returns a performance finding indicating the number of render-blocking stylesheet resources detected on the target page, helping identify CSS files that delay initial page rendering.

## 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/halowerk-tempo-stylesheet-render-blocking-resources-check-177a3ae7/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)