Originality.ai

Originality.ai is an AI content detector aimed at a specific audience: publishers, SEO agencies, and anyone buying freelance writing who wants to know whether they’re paying for human work. Founder Jon Gillham previously ran content-marketing agencies, which explains why the product is organized around editorial workflows rather than classrooms — a sharp contrast with Turnitin.

Each scan runs AI detection and plagiarism checking together, returning a probability score with sentence-level highlighting. The detector ships in multiple versions — a stricter Turbo model for zero-tolerance publishing and a Lite model tuned for fewer false positives — and targets output from GPT-4-class models, Claude, and Gemini, including lightly paraphrased text. In independent third-party benchmarks of AI detectors, Originality.ai routinely lands at or near the top for accuracy, though no detector is infallible.

Two features stand out for agencies. Full Site Scan crawls an entire domain and scores every page — handy before acquiring a site. And the free Chrome extension can watch a Google Doc’s revision history to replay how a document was written, far stronger evidence of human authorship than any probability score.

Key Features

• Combined AI detection and plagiarism scan with per-sentence highlighting
• Multiple detection models (Turbo for strictness, Lite for fewer false positives)
• Full Site Scan to audit every page of a domain in one job
• Chrome extension with Google Docs writing-replay for authorship proof
• Fact-checking aid and readability scoring alongside detection
• Team management with seats, shareable reports, and activity logs
• API access for integrating scans into publishing pipelines

Pricing

Credits are the unit — 1 credit scans roughly 100 words.

• Pay-as-you-go: One-time credit packs starting around $30, no subscription
• Pro (~$15/month): Monthly credit allowance plus team features and Site Scan
• Enterprise: Higher volume, API scale, and priority support at custom pricing

Best For

Content agencies and SEO teams verifying outsourced articles before publishing, website flippers auditing a domain’s content before purchase, and editors who need a paper trail — the Google Docs replay — rather than accusations based on a score alone.

Limitations

Detection is probabilistic: polished human writing sometimes flags as AI, and heavily edited AI text can slip through. Treating a score as a firing offense for a freelancer is unfair without corroboration. Credits also run out faster than expected on long documents, and support for non-English content lags well behind English.