# Tempo Halowerk – Stylesheet Time to First Render (Renderstart)

> Tempo Halowerk – Stylesheet Time to First Render (Renderstart) 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).

Measures the time-to-first-render (Renderstart) for a stylesheet resource on a given public URL, returning a performance finding.

## Facts

- Endpoint: POST https://tempo.halowerk.com/v1/pruef/tempo/renderstart/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/tempo-halowerk-stylesheet-time-to-first-render-renderstart-67b2c784
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ZExmB1EAcD8-esTbHGG5X

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-stylesheet-time-to-first-render-renderstart-67b2c784 -d '<json body>'
```

Example prompt: Can you check how long it takes for the stylesheet at https://example.com/styles/main.css to reach its visible render start?

## When to prefer this

Use this endpoint when you specifically need to measure the time-to-first-render (Renderstart) for a stylesheet resource on a public URL, as opposed to checking other asset types (images, scripts, fonts) or other performance metrics (TTFB, DNS resolution time, total load time). It is distinct from the sibling script render-start endpoint.

## Known failure modes

- URL is not publicly accessible — endpoint cannot reach the target
- URL does not serve a stylesheet resource — finding may be invalid or empty
- Timeout if the target server is very slow to respond
- Invalid CSS selector results in no matching object found
- DNS resolution failure for the target domain

## How this service works

Prüft am Objekt stylesheet den Befund Zeit bis zum sichtbaren Renderstart.

## Output

Returns a performance finding containing the measured time (in milliseconds or similar unit) until the stylesheet resource first contributes to a visible render on the page, along with metadata about the tested URL and resource.

## 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-stylesheet-time-to-first-render-renderstart-67b2c784/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)