SynthID detector
Check content for a SynthID watermark.
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0 words3,000 words per free check
About this check
How SynthID works
SynthID embeds a statistical pattern directly into generated output — token selection in text, pixel-level adjustments in images, the spectrogram in audio. Because it lives in the content rather than alongside it, it survives compression, cropping and re-encoding far better than metadata does.
Why detection is restricted
A watermark that anyone can detect is a watermark anyone can learn to remove. Google keeps the detector closed, which makes the scheme robust and makes independent verification impossible at the same time. That trade-off is inherent, not an oversight.
What this page does
It runs every check that can run, reports SynthID as 'Not verifiable', and tells you plainly why. If Google opens a verification interface, this page starts returning real SynthID results with no change on your side.