How much of this text was written by AI?

Paste any text and get the percentage that is AI-generated, with every sentence highlighted. Works on fully AI-written, human-written and mixed documents.

Try it free API docs

0 / 1,500 words

Your result will appear here, with every sentence highlighted.

The free demo checks up to 1,500 words, a few times per hour. Nothing you paste here is stored. Create a free account for longer texts, history and an API key.

Sentence-level percentages

Not just a yes/no verdict: see exactly which sentences look AI-written and what share of the text that is.

Ensemble of signals

A fine-tuned transformer classifier, zero-shot perplexity analysis (Binoculars) and writing-style features, calibrated together.

Built to resist evasion

Trained on paraphrased and “humanized” text, and it strips hidden characters and look-alike letters before analysis.

Developer API

One POST request returns the AI percentage and per-sentence results with character offsets. Free tier included.

Add AI detection to your app

Use the same engine from your LMS, CMS, hiring pipeline or moderation tool. Create a key in the dashboard and send text over HTTPS.

Read the API docs

curl -X POST https://aidetector.duckdns.org/v1/detect \
  -H "X-API-Key: sk_live_..." \
  -H "Content-Type: application/json" \
  -d '{"text": "...", "return_segments": true}'

{
  "ai_percentage": 63.2,
  "human_percentage": 31.5,
  "mixed_percentage": 5.3,
  "label": "mostly_ai",
  "confidence": 0.91,
  "segments": [{ "start": 0, "end": 142,
     "ai_probability": 0.97, "label": "ai" }]
}