GPTZero tells you if it's AI. Credify tells you where the patterns are. A 5-signal ensemble: dual-path neural classifier, AI phrase density, perplexity, burstiness, and repetition: scores every sentence so you know exactly what to address.
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 goes from detection to E-E-A-T audit to rewrite: in one place, no signup.
| 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 | ✓ | — | — |
Most AI detectors give you a single verdict: “AI” or “Human”: and stop there. This free AI detector uses a 5-signal ensemble to return a calibrated 0–100% probability score with sentence-level breakdowns, so you can see which parts of your content read as AI-generated and which read as human. The dual-path neural classifier routes casual and academic text separately, reducing false positives on formal writing that single-model AI detectors commonly over-flag.
SEO teams use this AI detector to audit AI-assisted content before publishing. Editors use it to check writer submissions without relying on a single-model verdict. Students use the AI detector to verify their own writing won't be falsely flagged by institutional tools. Teachers use it to distinguish between AI-generated and student-authored work at the sentence level: not just the document level.
After running this AI detector, use the AI Humanizer to rewrite flagged sections, paste the content into the E-E-A-T Checker to score quality signals, check sentence structure with the readability checker, and remove passive-voice patterns that this AI detector flags as high-probability AI signals with the passive voice remover.
Detect, humanize, and verify: run the full AI content workflow.
Free, no signup, no limits. 5-signal ensemble detection with sentence-level breakdown and a direct path to the fix.