Google's SynthID Detector is a portal where you upload a file and learn whether it carries the invisible SynthID watermark that Google and its partners embed in AI-generated content. It answers one question well and leaves the harder question open. This article covers how the portal works, how to get in, how to read what it tells you, and where its answer stops. If you want the broader picture of who applies SynthID in the first place, start with our SynthID adoption overview.
What the Portal Is
Google announced the SynthID Detector at I/O in May 2026 as a standalone verification surface. Until then, checking for the watermark meant asking the Gemini app about an image or using "About this image" in Search and Chrome. The portal accepts direct uploads instead: images, audio, video, and text.
Two things distinguish it from the older routes. It handles more than images, which matters now that SynthID marks audio and video from several vendors. And it localizes its findings: when only part of a file carries the watermark, the portal highlights which portion, so an image with an AI-generated sky over a real foreground shows up differently than a fully generated frame.
The scale behind it is what makes the check meaningful. Google has applied SynthID to over 100 billion pieces of content across its products, and since May 2026 the mark also lands in every image from ChatGPT and the OpenAI API, plus content from Nvidia, Kakao, and ElevenLabs.
How to Get Access
The portal is not open to the public yet. Google is rolling it out through a waitlist, with journalists, media professionals, and researchers reviewed first. You apply through the form linked from the announcement post, and approved accounts receive a portal link by email. Reported review times run from a few days to about two weeks for the priority groups. There is no published timeline for general availability.
If your work involves verifying incoming images regularly, apply with your professional affiliation. Everyone else can run the same underlying detection through the routes in the alternatives section without waiting.
How to Read a Result
A positive result means the detector found the statistical pattern SynthID embeds at generation time. For a whole-file hit on an image, that is strong evidence the image came from a participating generator. For a partial hit, the highlighted region tells you where generated content sits inside otherwise unmarked material, which is often the more useful finding: a real photograph with a generated object composited in is exactly the case that fools human review.
A negative result is where reading discipline matters. The detector reports that it found no SynthID watermark. That is all it reports. The file may come from a generator that never participated in watermarking, the mark may have been degraded by heavy cropping, re-encoding, or screenshotting, or the content may be a genuine photograph. The portal cannot distinguish between those three cases, and treating "no watermark" as "not AI" is the single most common misreading of any detection tool.
Detection is also probabilistic at the edges. SynthID survives normal compression and resizing well, and Google engineered it to be robust, but robustness has limits and the classifier returns confidence, not certainty.
What It Cannot Tell You
The portal checks for one mark: SynthID. Its coverage is exactly the SynthID ecosystem, which as of August 2026 means Google's generators, OpenAI's images, and content from Nvidia, Kakao, and ElevenLabs. Images from Midjourney, Stable Diffusion, Flux, and every locally run model carry no SynthID and never will unless those vendors join. Our generator-by-generator comparison tracks which tools mark their output and how.
It also cannot authenticate a photograph. Finding no watermark in a real photo is the expected outcome, but it is the same outcome as an unmarked fake. The detector's design goal is catching participating generators' output, not proving a capture happened. That distinction, detection versus provenance, is the subject of our comparison of the two approaches, and it is why a serious authenticity claim needs evidence that starts at the camera rather than a scan that ends at one vendor's watermark.
Checking Without Portal Access
While the waitlist holds, the same detection is reachable three ways. The Gemini app runs SynthID checks on uploaded images when you ask whether an image is AI. "About this image" in Google Search and Chrome exposes the check for images Google can fetch, without an upload. OpenAI's Verify tool reads the two marks OpenAI applies to its images, SynthID and the C2PA manifest, and since July 2026 accepts audio as well.
The C2PA half you can read yourself. Our free AI Photo Checker parses Content Credentials directly in your browser, with no account and no upload to anyone's server. When a ChatGPT image still has its metadata, the manifest names the generator outright, which is a plainer statement than a watermark probability. When metadata is stripped, which platforms do routinely, the pixel watermark is what remains, and that check belongs to Google's and OpenAI's surfaces.
When the Detector Is the Wrong Tool
Use the detector when the question is "did this come from a participating AI generator." Use something else when the question is "is this photograph real."
The second question comes up when a photo is disputed: a contest entry, a news submission, an insurance claim, a marketplace listing. There, absence of a watermark proves nothing, and AI detectors that guess from pixels alone flag real photos often enough to make accusations unreliable. What settles the question is provenance: whether an original capture exists and whether the disputed image is consistent with it. That comparison, original against published copy, is what Lumethic's verification runs, and it works for photos regardless of which generator ecosystems exist around them.
The two approaches are complements, not rivals. A newsroom triaging a suspicious inbound image reasonably runs the watermark check first, because a positive hit ends the discussion in seconds. When the check comes back empty, the real work starts, and that work is provenance.
Frequently Asked Questions
Is the SynthID Detector available to everyone?
Not yet. Access runs through a waitlist, with journalists, media professionals, and researchers reviewed first. Approved users get a portal link by email. The detection itself is publicly reachable through the Gemini app and "About this image" in Search and Chrome.
Does the SynthID Detector find ChatGPT images?
Yes. OpenAI applies SynthID to every image from ChatGPT and its API since May 19, 2026, and the portal detects the same mark regardless of which partner embedded it.
Does it detect Midjourney or Stable Diffusion images?
No. Those generators do not apply SynthID. A Midjourney image comes back with no watermark found, the same result as a real photograph.
If the detector finds no watermark, is the image real?
No. The result means only that no SynthID mark was found. The image could be from a non-participating generator, the mark could have been destroyed by processing, or the image could be genuine. Establishing that a photo is real requires provenance evidence, not the absence of one vendor's watermark.
Can SynthID be removed from an image?
Google designed it to survive normal handling like compression, moderate cropping, and filters. Determined adversarial processing can degrade it, which is one more reason a missing watermark is weak evidence of anything.
