# AI Watermark Checker

URL: https://symelo.com/tools/ai-watermark-checker

Check images for Content Credentials (C2PA), AI labels, generator settings and Stable Diffusion's invisible watermark, and text for hidden characters, in the browser.

## Usage

1. Drop, paste or choose images (JPEG, PNG, WebP, AVIF, HEIC, GIF or TIFF), or switch to Text and paste the text to check.
2. Each file is checked in the browser: read the verdict (AI-generated, edited with AI, AI hints, Content Credentials without AI, or none found) and open each check for its details.
3. Copy the report as JSON, or for text copy or download it without its hidden characters.

## Behavior

- Images: Content Credentials (C2PA) with their signer, actions and IPTC digital source type, a check of the COSE signature against the certificate in the file and of the image's data hash; IPTC digital source types and AI properties in XMP; prompts and settings saved by AUTOMATIC1111, ComfyUI, InvokeAI, NovelAI, Fooocus, SwarmUI and Midjourney; the invisible DWT-DCT watermark of Stability AI's Stable Diffusion XL, 1.x and 2.x reference code; and AI tool names in EXIF and XMP fields.
- Text: zero-width and invisible characters, Unicode tag characters and variation-selector sequences (hidden messages are decoded), bidirectional controls, control and private-use characters, unusual spaces such as U+202F, and words that mix Latin with Cyrillic or Greek look-alike letters.
- In the browser, files are never uploaded. POST /api/v1/ai-watermarks/check checks up to 5 files or texts per request, 10 MB each, as multipart/form-data or base64 JSON, without an API key, and at most 300 images an hour across all callers. Files are checked in an isolated process, never stored or logged, and deleted from memory as soon as their check ends. Respect Retry-After on 429 and 503.
- A result without a watermark does not mean a person made the file: metadata is easily removed, Google's SynthID and other providers' invisible watermarks can only be read by their own detectors, and statistical text watermarks need the model's key. C2PA signatures are not checked against the C2PA trust list.

- [API reference](https://symelo.com/docs/ai-watermark-checker-api.md)
- [OpenAPI schema](https://symelo.com/api/v1/ai-watermarks/openapi.json)

## Related pages

- [All tools](https://symelo.com/tools)
- [Agent documentation](https://symelo.com/llms.txt)