# Google SynthID watermark checklist

Companion guide: https://chadesheppard.com/synthid-detector
Chad's video: https://www.youtube.com/shorts/YxckyIuOXLA

## The rule that matters

“SynthID not detected” does not mean “confirmed real.” SynthID checks for a hidden watermark used by supported AI tools, not every possible AI generator.

## Check a file

1. Open Google's official detector at https://synthid.com/ and sign in using an option shown there. Google opened it globally in English on October 7, 2026.
2. Follow the current access and upload instructions. Gemini may also support watermark verification for your file: https://gemini.google.com/
3. Upload only content you have permission to share. Avoid sensitive files; read the privacy terms.
4. Prefer the original file. Record any edits, cropping, or re-encoding you know about.
5. Save the exact watermark result. If the tool cannot check the file, write “not checked,” not “not detected.”
6. Investigate the original uploader and independent evidence before sharing.

## Optional Gemini request

Check this file for a SynthID watermark. Report the watermark result separately from any visual guesses. If no watermark is detected, explain why that does not establish whether the content is real or AI-generated.

An assistant's visual guess is not a watermark-verification result. Claude can help organize your evidence, but cannot replace Google's actual detector.

## Evidence notes

- File/source URL:
- Original uploader:
- Checked file version:
- Tool and date:
- Exact result:
- Known creator disclosure:
- Independent sources:
- What remains unknown:

## Read the result carefully

- Detected: evidence of a SynthID watermark in the checked content, not proof that every frame, sound, or claim is AI-generated.
- Not detected: no SynthID watermark found in this check; real-or-AI remains unresolved.
- Unsupported/error: no usable check was performed.

Chad's Short describes his own examples, not a controlled accuracy benchmark.