GPTZero tells you if it's AI. Credify tells you what to do about it. A 5-signal ensemble — dual-path neural classifier, AI phrase density, perplexity, burstiness, and repetition — scores every sentence, then the E‑E‑A‑T Checker fixes it. Free, no signup.
Four independent signals combined into one calibrated score — no single model makes the call.
Dual-path routing: casual text uses a classifier trained across 14 LLM families including GPT-4/5, LLaMA, Anthropic, and Mistral. Academic text (citation markers detected) uses a classifier trained on human vs AI research abstracts. Both score in 500-token chunks.
Counts scholarly GPT flourishes per 100 words — "delve into", "it is worth noting", "plays a crucial role", "multifaceted", "transformative" and similar. GPT-4 academic text uses these at 3–6× the density of human researchers.
Measures how predictable the full document is to a language model. AI text scores low perplexity (very predictable); natural human writing is less predictable. Calibrated against a conversational baseline.
Scores every sentence with a local language model and measures the variance. AI text is uniformly predictable — low variance. Human writing is bursty — some sentences are simple, others complex. High variance = likely human.
Counts repeated 3-word phrases across the text. AI outputs over-reuse common patterns even when paraphrasing.
Paste text, enter a URL, or upload a PDF/DOCX.
Each signal scores your text independently.
Signals combined by weight → 0–100% AI probability + confidence level.
Every sentence scored separately so you see exactly which parts read as AI.
High score? Use the E‑E‑A‑T Checker to rewrite with human signals.
Other detectors stop at detection. Credify is the only free tool that takes you from detection to a fixed, rankable piece of content.
| Feature | Credify | GPTZero | Originality.ai |
|---|---|---|---|
| Detection method | 5-signal ensemble | Single classifier | Single classifier |
| Per-sentence scoring | ✓ | ✓ | — |
| Signal breakdown | ✓ | — | — |
| Confidence level | ✓ | — | — |
| URL analysis | ✓ | — | ✓ |
| File upload (PDF/DOCX) | ✓ | ✓ | ✓ |
| E-E-A-T quality score | ✓ | — | — |
| AI-powered rewrite | ✓ | — | — |
| Free tier | ✓ unlimited | Limited | Pay per credit |
| No signup required | ✓ | — | — |
Everything you need to know about AI content detection.
Most AI detectors give you a single verdict — "AI" or "Human" — and stop there. Credify uses a 5-signal ensemble to return a calibrated 0–100% probability score with sentence-level breakdowns, so you can see exactly which parts of your content read as AI-generated and which read as human. The dual-path neural classifier handles both casual and academic content differently, making it significantly more accurate on formal writing that fools single-model detectors.
SEO teams use it to audit AI-assisted content before publishing. Editors use it to check writer submissions. Students use it to verify their own writing won't be falsely flagged. After detection, run the AI Humanizer to rewrite flagged sections, or paste the content into the E-E-A-T Checker to score and fix the quality signals that affect rankings. Check grammar and readability after rewriting to confirm the output is clean and clear.