What is SynthID and how do you check for it?
SynthID is an invisible watermark developed by Google DeepMind. It is embedded in an image's pixels, or within audio and video, in a way that the eye and ear cannot detect. Unlike Content Credentials, it is designed to stay in place in most cases, even if the file metadata is removed.
Which content has it?
Images, videos and audio created with Google tools such as Gemini, Imagen, Veo and Lyria carry SynthID. According to Google, other companies such as OpenAI, NVIDIA and Kakao also started using SynthID in their own tools in 2026.
Text generated by Gemini also carries a text version of SynthID. But the text watermark works differently and can be checked only by Google.
How do you check for it?
In October 2026, Google opened its SynthID Detector tool to everyone. You can sign in with your Google account and upload an image, video or audio file to find out whether it carries the watermark. The number of checks per day is limited. The Gemini app can also tell you whether an image you show it carries SynthID.
Our checking tool does not check for SynthID itself, because Google's terms of use do not allow that tool to be used automatically. Instead, our reports link to Google's tool.
What does the result mean?
If SynthID is found, the content was most likely created or edited with an AI tool that uses this watermark. If it is not found, that does not show the content was made by a human: it may have been created with a tool that does not use SynthID. The watermark may also not survive every edit.
Frequently asked questions
What is the difference between SynthID and Content Credentials (C2PA)?
Content Credentials are a signed record added to the file; they are easy to read but can be removed. SynthID is embedded in the content itself; it is hard to remove but can be read only with Google's tool. Companies use the two together.
Does SynthID survive in an image uploaded to social media?
SynthID is designed to stay readable after common changes such as compression and cropping, but there is no guarantee. You can try checking an image you downloaded from social media with Google's tool.