# Tempo Halowerk TTFB Stylesheet Check

> Tempo Halowerk TTFB Stylesheet Check is a paid API for AI agents from tempo.halowerk.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-16).

Measures and reports the Time to First Byte (TTFB) for a stylesheet resource at a given public URL.

## Facts

- Endpoint: POST https://tempo.halowerk.com/v1/pruef/tempo/ttfb/stylesheet
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/tempo-halowerk-ttfb-stylesheet-check-b8c7b5ea
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_iXssViNsFwJ9YPUn1wGFY

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-ttfb-stylesheet-check-b8c7b5ea -d '<json body>'
```

Example prompt: Can you check the Time to First Byte for the stylesheet at https://example.com/styles/main.css and tell me how fast the server is responding?

## When to prefer this

Use this endpoint when you specifically need to measure the Time to First Byte for a stylesheet (CSS) resource, as opposed to measuring TTFB for a full page, video, iframe, or API response. It is the right choice when diagnosing CSS delivery performance, CDN configuration, or server response time for individual stylesheet assets.

## Known failure modes

- Stylesheet URL is not publicly accessible (returns error or connection refused)
- URL points to a non-stylesheet resource, producing irrelevant TTFB data
- Provided URL exceeds 2048 characters or is malformed
- CSS selector matches no element or multiple elements (first match used)
- Target server is too slow and request times out
- Invalid user_agent string pattern causes request rejection

## How this service works

Prüft am Objekt stylesheet den Befund Zeit bis zum ersten Byte.

## Output

Returns a performance finding for the TTFB (Time to First Byte) of the specified stylesheet resource, including the measured response time and an assessment of whether the value is within acceptable ranges.

## 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-ttfb-stylesheet-check-b8c7b5ea/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)