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AI Detectors

Classifiers that estimate whether a passage was written by a language model. Every one of them produces false positives on human writing, and none publishes an independently audited error rate, so we record the vendor's own accuracy claim and mark it as exactly that.

Tools in this category22
With a price read at the source15
With a free tier19
Reviewed hands-on0
Docs checked New

Decopy AI Detector

Free no-login AI detector handling up to 200,000 characters with shareable online or PDF reports.

AI Detectors from USD 9.99
Docs checked API New

Detecting-AI

Free AI detector taking 15,000 characters per scan without signup, plus detector and humanizer APIs.

AI Detectors from USD 7.00
Docs checked New

Grammarly AI Detector

Free AI detector from Grammarly returning a percentage AI score, with a Pro agent for flagged phrases.

AI Detectors from USD 12.00
Docs checked API New

Isgen

Multilingual AI detector with sentence-level highlighting, bulk scanning and an academic-priced plan.

AI Detectors from USD 8.00
Docs checked API New

Originality.ai

AI detection plus plagiarism, fact and readability checks aimed at web publishers and content agencies.

AI Detectors from USD 12.95
Docs checked API New

Pangram Labs

Research-led AI text detector for schools and platforms, with a free daily quota and a usage-based API.

AI Detectors from USD 20.00
Docs checked New

QuillBot AI Detector

Free AI detector inside QuillBot's writing suite, with sentence highlights and a 1,200-word free scan.

AI Detectors from USD 8.33
Docs checked New

Scribbr AI Detector

Free student-facing AI detector with paragraph-level feedback and a paid premium GPT-4-capable tier.

AI Detectors from USD 19.95
Docs checked API New

Winston AI

AI text, image and deepfake detection with plagiarism checking and site certification for publishers.

AI Detectors from USD 10.00
Established API New

GPTZero

AI text detector for educators and publishers with sentence-level highlighting and batch file scanning.

AI Detectors Freemium
Established API New

ZeroGPT

Free web AI text detector with highlighted sentences, plus paraphraser, summarizer and API plans.

AI Detectors Freemium
Listed New

JustDone AI Detector

AI detector in JustDone's student toolkit, publishing its own error rate and estimating Turnitin scores.

AI Detectors Freemium

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