# StableFace Reverse Face Search

> StableFace Reverse Face Search is a paid API for AI agents from stableface.dev, paid per call via x402, $0.2/call, status unknown (last checked 2026-09-15).

Performs a reverse face search across the web to find every page containing a given face, powered by FaceCheck.id

## Facts

- Endpoint: POST https://stableface.dev/api/facecheck/search
- Price: $0.2/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/stableface-reverse-face-search-0818bb40
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_WlCG0kGa9hpLEf3ymzTX2

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 stableface-reverse-face-search-0818bb40 -d '<json body>'
```

Example prompt: Search FaceCheck.id for every webpage containing the face in this photo — https://example.com/person.jpg — return up to 50 results and only include matches with a score of 85 or higher.

## When to prefer this

Use this endpoint when you need to find where a specific person's face appears across the public web, identify an unknown individual from a photo, or audit the online presence of a face. Prefer this over text-based image search when the query is a face rather than an object or scene. Best for identity research, due diligence, or verification use cases where facial biometrics are the search key rather than metadata or text.

## Known failure modes

- No face detected in the provided image — returns empty results or error
- Image URL is not publicly accessible or returns a non-image content type
- Base64 data URL is malformed or too large
- Score threshold too high — filters out all results, returning empty array
- FaceCheck.id upstream unavailable — service error propagated
- Payment not attached or insufficient USDC — x402 payment required error
- Rate limit or quota exceeded on FaceCheck.id backend

## How this service works

Pay-per-request reverse face search powered by FaceCheck.id. Find every page on the web that contains a given face.

## Output

A ranked list of web pages (up to the requested limit) where the face appears, each with a match confidence score from 0–100. Optionally includes base64-encoded face thumbnail crops. Results are sorted by score descending, filtered to only those meeting the minScore threshold.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "format": "uri",
   "description": "Image containing a face. Accepts a public http(s) URL or a data URL (data:image/...;base64,...) when you want to send bytes directly without hosting."
  },
  "limit": {
   "type": "integer",
   "default": 20,
   "maximum": 200,
   "minimum": 1,
   "description": "Maximum number of matches to return, ranked by score descending"
  },
  "minScore": {
   "type": "number",
   "default": 0,
   "maximum": 100,
   "minimum": 0,
   "description": "Drop matches with score below this threshold. 85+ is typically a strong match."
  },
  "testingMode": {
   "type": "boolean",
   "default": false,
   "description": "Run in FaceCheck testing mode. Only scans ~100k faces, no credits consumed, but results are not meaningful. Use for integration tests only."
  },
  "includeThumbnails": {
   "type": "boolean",
   "default": false,
   "description": "Include a base64 data-URI thumbnail of each matched face. Off by default since thumbnails dominate response size and are rarely useful to agents."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/stableface-reverse-face-search-0818bb40/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from stableface.dev](https://www.zero.xyz/host/stableface.dev/llms.txt)