# tempo.halowerk.com – Image Render-Start Time Check

> tempo.halowerk.com – Image Render-Start Time 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).

Measures the time-to-first-visible-render (Renderstart) for an image resource at a given public URL.

## Facts

- Endpoint: POST https://tempo.halowerk.com/v1/pruef/tempo/renderstart/bild
- 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-image-render-start-time-check-dfe2d826
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_l-lGGzpI7ysUqM_ru1iFb

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-image-render-start-time-check-dfe2d826 -d '<json body>'
```

Example prompt: Check how long it takes for the main hero image at https://example.com/images/hero.jpg to visually start rendering — I want the time-to-renderstart measurement.

## When to prefer this

Use this endpoint when you need to specifically measure the time-to-first-visible-render (Renderstart) for an image resource, as opposed to other timing metrics like TTFB or TLS handshake time. It is most appropriate for web performance auditing, continuous monitoring of image load UX, or diagnosing why images appear slow to users. Choose it over page-level render-start checks when you need per-image granularity rather than full-page metrics.

## Known failure modes

- Target URL is not publicly accessible or returns a non-200 status — endpoint returns an error
- Image URL resolves to a non-image resource — measurement may fail or be invalid
- CSS selector matches no element or multiple elements — first match used or error returned
- Target server is too slow or times out during probe — timeout error returned
- Malformed URL or URL exceeding 2048 characters — validation error returned

## How this service works

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

## Output

Returns the measured time-to-first-visible-render (Renderstart) for the specified image resource, indicating how long it takes from request initiation until the image begins appearing visually in the browser.

## 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-image-render-start-time-check-dfe2d826/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)