What Is the SynthID Detector?
The SynthID Detector is a free web tool that lets anyone check whether an image, video, or audio file carries Google’s invisible AI watermark. With generative AI tools pumping out images, videos, and even songs in recent years, it’s hard to spend time online without wondering whether what you’re seeing or hearing is real. Google, itself one of the largest purveyors of generative AI, is now making it easier to spot its output.
Google introduced SynthID in 2023, which adds an imperceptible label to AI-generated content. Until recently, though, there was no way for regular users to actually check for that label. In 2025, Google launched a limited version of the SynthID Detector for certain researchers and journalists, and now it’s available for everyone. While that’s good news for anyone looking for a way to verify whether a piece of content was generated with AI, the tool is far from foolproof.
How the SynthID Detector Works
Since SynthID’s launch, Google’s Gemini AI model has embedded a watermark in everything it creates. The SynthID Detector works by scanning for that watermark and giving users a simple yes or no answer as to whether one was found.
Using the tool is straightforward:
Go to SynthID.com.
Upload an image, video, or audio file.
Wait a few seconds for Google to return a result.
That’s a big improvement over Google’s previous process. Before now, users could ask Gemini itself whether a piece of content was AI generated. But for anyone who doesn’t trust generative AI, it’s hard to take Gemini at its word — and it’s an immediate no-go for people who are trying to avoid the technology altogether.
The SynthID Detector also allows users to scan for watermarks embedded in content created by Google’s SynthID partners, which wasn’t possible before. That means the new tool can tell whether media was made with AI models from OpenAI, NVIDIA, and Kakao, in addition to Gemini. Apple also participates in SynthID, but support for the detector to identify its creations is still in the works.
How Reliable Is the SynthID Detector?
Because the SynthID Detector simply checks for a watermark rather than analyzing media for patterns that indicate AI use, it should eliminate the chance of false positives. That simplicity introduces its own limitations, though.
The most obvious limitation is that it can’t detect media made with AI models that don’t use SynthID, such as Meta’s tools. The SynthID Detector is also limited to telling users whether it finds a label in an uploaded file, without providing any information on what parts of it were AI-generated.
Google says its SynthID signatures persist even if AI generations are edited after being created. While there’s no guarantee that an enterprising faker won’t find a way around that eventually, the company does seem to be taking steps to avoid it. A Google spokesperson reportedly said that users are limited to around 10 checks per day in order to prevent them from using the detector’s output to find a way to remove SynthID. Users also have to be logged in to either a Google, OpenAI, or Apple account to use the SynthID Detector.
How Does the SynthID Detector Compare to Other AI Detectors?
The SynthID Detector isn’t the only generative AI detector available, but despite its limitations, it’s likely one of the most reliable. SynthID partner OpenAI runs its own detector tool, which can pick out AI-confirming metadata as well as SynthID watermarks.
Meta embeds its own watermark, called Content Seal, into its AI creations and offers a web-based detector tool, though a 2026 report from Reuters found that it sometimes failed to accurately spot them. Companies like Anthropic and Microsoft have also begun watermarking AI media, but don’t currently offer consumer tools to detect them.
The downside of all of these tools is that they’re designed to detect a specific AI marker. No reliable detector exists that can spot generative AI across the board. Many researchers have developed their own AI-spotting tools, but they’re not available to the public. And when it comes to the general-purpose AI detectors that are openly available, their results are unreliable and prone to flag human-created work as AI content.
The SynthID Detector is a simple, free way to check whether an image, video, or audio file was created with AI — as long as that AI came from Google or one of its partners. It won’t catch everything, and it can’t tell you how much of a file was altered. But for a quick, low-effort verification, it’s one of the more trustworthy options currently available to the public.
