Google SynthID — Google DeepMind

Generative AI can help us all to be more creative, productive, and innovative. But it can be hard to tell the difference between content that’s been AI-generated, and content created without AI.
Google SynthID is our watermarking tool, designed specifically for AI-generated content. It empowers users to identify AI-generated (or altered) content, helping to foster transparency and trust in generative AI.
SynthID embeds digital watermarks directly into AI-generated images, audio, text or video. The watermarks are embedded across generative AI consumer products, and are imperceptible to humans – but can be detected by SynthID's technology.
SynthID adds an invisible digital watermark to an AI-generated image (or video segment). The watermark doesn’t change the image or video quality. It’s added the moment content is created, and designed to stand up to modifications like cropping, adding filters, changing frame rates, or lossy compression.
SynthID embeds a watermark into any audio generated or published through our AI music generation model Lyria or the podcast generation feature of Notebook LM.
It’s inaudible to the human ear, and can’t be altered by common modifications like adding noise, MP3 compression, or changing the speed of the track
We’ve expanded SynthID to watermarking and identifying text generated by the Gemini app and web experience.
Large language models generate text one word (token) at a time. Each word is assigned a probability score, based on how likely it is to be generated next. So for a sentence like “My favourite tropical fruits are mango and…”, the word “bananas” would have a higher probability score than the word “airplanes”.
SynthID adjusts these probability scores to generate a watermark. It's not noticeable to the human eye, and doesn’t affect the quality of the output.
Want to check if an image or video was generated, or edited, by Google AI?
Simply upload the image, video or audio clip to your chat, and ask if it’s been created or altered by Google AI. Gemini, Search and Chrome will check for a SynthID watermark, and let you know if it finds one.
In 2025, we launched the SynthID Detector, a verification portal, to verify if a piece of content was watermarked with Google SynthID. After testing with journalists and media professionals and collecting their feedback, we’re expanding access to everyone.
With the new SynthID Detector, anyone can easily check if an image, video, or audio file was made with AI from Google or our partners, including OpenAI, NVIDIA, Kakao, and soon, Apple.
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