Free online AI detector and checker
Free Online AI Detector for Text and Images
Paste up to 20,000 characters of English text, upload a .txt or .md file, or drop in a photo. In seconds you get a verdict — on an essay you're grading, a review you don't trust, or a profile photo that looks too perfect. It works as an AI text detector and AI image detector, and it catches synthetic photos and deepfakes.
How detection works
How the Free Online AI Detector Works
Slop or Not doesn't rely on one trick. It checks the most reliable signal first and falls back in order.
- 1 · Watermarks
SynthID and Content Credentials
Google and OpenAI now stamp an invisible SynthID watermark into their images, and other tools add a C2PA Content Credential. When an image carries one, its source is recorded inside the file, so the verdict carries very high confidence and the result names the generator.
- 2 · OmniAID
Pixel-level image model
Watermarks get stripped when an image is screenshotted, re-saved, or deliberately scrubbed to hide its origin. When the metadata is gone, the OmniAID model reads the pixels for the artifacts AI generators leave behind, reaching about 90% accuracy on non-watermarked images in our internal tests.
- 3 · Text model
Transformer trained on human and AI writing
A fine-tuned transformer trained on a large corpus of human and AI writing scores the passage for AI fingerprints, reaching about 95% accuracy on text in our internal tests. Full, natural sentences give a more confident result than fragments or single lines.
Accuracy figures come from our internal tests and can vary with new AI models and methods built to trick detectors.
Support the project
We built on-device generative AI before Apple Intelligence existed
We're two engineers based in the EU, and we care a lot about privacy and on-device generative AI. We've spent years building privacy-first apps, and Slop or Not is one of them. It's free, and we never sell your data or hand it to anyone. If it earns a spot on your iPhone or Mac, going Pro keeps us independent and lets us keep fighting deepfakes and AI scams.
Free to download. Pro is an optional in-app upgrade.
More from Numen
Two more apps from the same two engineers. Both run on your device, and neither needs an account.
Private LLM
A Local AI chatbot for uncensored, open-source models, fully offline on iPhone, iPad, and Mac. It ships state-of-the-art OmniQuant and GPTQ quantization, running 3-bit models that match the 4-bit ones other apps ship.
Clean Links
Most tracking now hides behind link redirects. Clean Links unwraps short links and strips every tracking parameter from a URL before you share it, on iPhone, iPad, Mac, and the web.
Join our Discord to see what's next and help shape the roadmap.