// category · 9 tools · 0 open source
AI Detectors
Tools that estimate whether text was AI generated or copied. Useful signals, but none are infallible. Treat results as evidence, not verdicts.
This category covers tools that try to answer one question: was this made by AI? It includes AI text detectors used by teachers and publishers, watermark checkers, provenance readers for images and video, and classifiers that flag deepfakes. They work in very different ways, and knowing which kind you are using matters more than any single accuracy claim.
Text detectors. Turnitin, GPTZero, Pangram and Originality.ai estimate how likely a passage is to be machine written. They give a probability, not proof. Independent tests such as the RAID benchmark measure detectors across many domains and against 11 attacks, including paraphrasing, misspellings and homoglyphs, because simple edits can change a detector's verdict. Our guide on whether AI detectors are accurate covers false positives, including the risk for non native English writers.
Watermarks. SynthID is Google DeepMind's invisible watermark for images, video, audio and text. Since October 2026 Google's SynthID Detector portal has been open to everyone, and it recognizes content from Google and partner companies. A detected watermark is strong evidence; a missing one tells you little, because most generators do not use SynthID. See our SynthID Detector guide.
Provenance. Content Credentials are signed C2PA records that document where a file came from and how it was edited. They work for real photos as well as AI images, but disappear if a platform or screenshot strips the metadata.
Deepfake classifiers. Hive and Reality Defender scan unlabeled images, video and audio for signs of generation or manipulation. Research on real world deepfakes found that open source detectors lost close to half their measured performance compared with older academic test sets, so treat any classifier score as a lead to investigate.
The practical rule is to combine signals. Check the source, read any Content Credentials, look for a watermark, then run a classifier, and never punish a person on one detector score alone. Our deepfake detection guide has a step by step checklist, and what is AI detection explains the main methods in plain language.
Pangrampangram.comAI text detector for educators and publishers that estimates how much of a document was AI generated, with a free daily word allowance and paid plans.Integrity & DetectionFreemiumHN 5
Content Credentials Verifycontentcredentials.orgFree web tool that reads C2PA Content Credentials in a file and shows its signed provenance history, including whether AI tools were used to create or edit it.Integrity & DetectionFree
GPTZerogptzero.meAI text detector used by educators to estimate whether writing was produced by language models, with writing reports.Integrity & DetectionFreemium
Hive AI Content Detectionthehive.aiHive's deepfake and AI generated content detection APIs score images, video and audio, name the likely generator, and come with a free Chrome extension.Integrity & DetectionSee site
OpenAI Content Verificationopenai.comOpenAI's free checker and Content Provenance API that look for its SynthID watermarks and C2PA data in images and audio made with ChatGPT, Codex or the API.Integrity & DetectionFree
Originality.aioriginality.aiAI content and plagiarism checker aimed at publishers and content teams.Integrity & DetectionPaid
Reality Defenderrealitydefender.comEnterprise deepfake detection for audio, video and images across live calls, meetings and uploaded files, delivered through an API and integrations.Integrity & DetectionSee site
SynthIDdeepmind.googleGoogle DeepMind's invisible watermark for AI images, video, audio and text. Files can be checked in the SynthID Detector portal, open to all since October 2026, or in Gemini.Integrity & DetectionFree
Turnitinturnitin.comLong standing academic integrity platform offering similarity checking, AI writing indicators and feedback tools for schools.Integrity & DetectionPaid// guides
Guides to AI detectors
What Is AI Detection? A Plain English Guide
What is AI detection? A plain English guide to how AI detection software works, what an AI detection report shows, its limits and Google Classroom options.
ChatGPT Watermark: How OpenAI's textGrain Works
Does ChatGPT have a watermark? In the EU, yes: OpenAI's textGrain hides a pattern in word choices. How it works, who can detect it, and what it can't prove.
What Is Claudish? Why AI Text Is Hard to Read
What is Claudish? The dense style of AI coding agents, what a new study found about why AI text is hard to read, and what it means for spotting AI writing.
How Does Turnitin Detect AI? What the Score Means
How does Turnitin detect AI? It scores overlapping prose segments by sentence. What it skips, why 1 to 19 percent shows an asterisk, and what to do if flagged.
How to Detect AI Writing: A Step by Step Guide
How to detect AI writing: read for the patterns, check facts and sources, run two detectors, ask for drafts, then talk to the writer. A careful method, free.
Originality.ai vs GPTZero: Which Should You Use?
Originality.ai vs GPTZero in 2026: free limits, prices, what the Epoch AI test found on human and AI text, and which detector fits publishers or teachers.
RAID Benchmark: How to Read the AI Detector Board
The RAID benchmark tests AI text detectors on 6 million samples with attacks. What it measures, how to read the leaderboard, and why 99 percent scores mislead.
Pangram vs Turnitin: Which Should You Use?
Pangram vs Turnitin in 2026: freemium plus LMS vs campus only AI detection, what the Springer study found, and which tool fits schools, teachers, and students.
Best Free AI Detector in 2026: Top Picks
Best free AI detector in 2026: Pangram, GPTZero, ZeroGPT and Originality.ai free limits, who each fits, and how to use scores without false accusations.
Originality.ai vs Turnitin: Which to Use?
Originality.ai vs Turnitin in 2026: 100 free credits vs campus licenses, how AI Allowance differs from Turnitin scores, and what peer reviewed studies found.
How to Use Originality.ai for Free
How to use Originality.ai for free in 2026: 100 free credits per account (about 10,000 words), how credits burn by model, privacy notes and how to read AI scores.
How to Use Pangram on Substack
How to use Pangram on Substack: Scan for AI text on web and iOS, creator controls, July 2026 limits, and how to read the human vs AI assisted estimate.
Pangram vs GPTZero: Which Should You Use?
Pangram vs GPTZero in 2026: free plans, Pangram 4 and GPTZero 4o, what independent studies found, and which AI detector fits educators, publishers, and teams.
SynthID Detector: How to Check for AI Watermarks
Google's SynthID Detector is now open to everyone. How to check images, video and audio for its AI watermark, what results mean, the limits, and alternatives.
Deepfake Detection: Hive, SynthID and C2PA Compared
Deepfake detection in 2026: how Hive's deepfake detector, SynthID watermarks and C2PA Content Credentials work, how accurate they are, and a checklist.
Are AI Detectors Accurate? What 2026 Studies Show
Are AI detectors accurate? What 2026 studies found on Turnitin, GPTZero, Originality.ai and Pangram, false positives, edited text, and what to do if flagged.
GPTZero vs Turnitin: Which AI Detector Is Better?
GPTZero vs Turnitin in 2026: who can use each, what scores mean, what independent studies found, GPTZero 4o and Turnitin's 2026 model updates, and which fits.
AI Model Fingerprinting Explained
AI model fingerprinting embeds ownership signals in LLMs. How the Fingerprinting Leaderboard works, SaTML 2026 findings, and how it differs from SynthID.