google made a tool to check if something's AI

google just opened SynthID to everyone — drop in an image, video, or audio clip and it tells you if AI generated it, by reading invisible watermarks its models (Nano Banana, Veo, Gemini) leave behind. OpenAI, Nvidia and Kakao back it too, and Apple's said to be joining soon. catch: it only flags media from models that chose to watermark — so the stuff most likely to fool you, the models that don't play along, carries no tag at all.e