Free tier, no signup

AI-text detection that tells you why.

One HTTP call returns a calibrated probability that text is AI-generated, and the exact signals that fired: buzzword density, stock phrases, uniform sentence rhythm, chat-UI artifacts. Most detectors hand back a bare number. This one hands back the evidence, so you can build a review UI a human can actually trust.

Try it now Read the docs

Live demo

Runs the real API on the free tier. Paste text and score it. Free-tier requests are metered per IP address, per day.

Why it is different

Most detectors	Tellcheck
A bare 0 to 100 score	Probability plus the specific signals that fired
Guess on any input	Abstains on short or non-English text, and says so
"Trust us" accuracy	A public benchmark with one command to reproduce
Account and dashboard to start	Free tier with no signup; a key when you need more

More than AI detection

The /v1/scan endpoint adds a text-integrity report to every result: hidden Unicode (zero-width and invisible characters), bidirectional controls (the Trojan-Source trick), and homoglyph spoofs (a Cyrillic letter hiding in a Latin word). It can hand back a sanitized copy too. One call defends an LLM pipeline against both AI slop and hidden-character injection. See the docs.

Integrate in one call

# free tier, no key
curl -s https://tellcheck-api.munzzyy.workers.dev/v1/detect \
  -H "content-type: application/json" \
  -d '{"text": "your text here"}'

With a key, send Authorization: Bearer sk_live_... and a batch of up to 50 texts per call. Full reference in the docs.

Pricing

Prepaid credits, one detection each. Credits never expire. Buy more anytime; they add to your key.

Free tier: 25 detections a day, no account. Batch calls cost one credit per text.