How Leap Tests Its AI Detector and Humanizer
Leap's tools run free in your browser: the detector scores text 0 to 100 from writing signals, and the humanizer is a cleanup pass for common AI writing habits. This page explains what that means, what we test, and what we do not claim.Try Leap's free AI tools
Free detection with no signup, run entirely in your browser. Nothing you paste is sent anywhere. The humanizer is a free cleanup pass that flags stock AI phrases, em dashes, invisible characters, and uniform sentence lengths so you can revise them yourself.Why this page exists
Pages like /review and /vs describe what different detectors and humanizers are for, and those descriptions cite this page. That only works if this page is specific about what Leap's own tools actually do and where their limits are. So here is the long version: what the detector measures, what the humanizer changes, and the claims we refuse to make.What the detector measures
Leap's AI detector runs in the browser, free, with no account. It scores text from 0 to 100 based on writing signals, and it highlights the sentences that weigh most in the score.- Sentence length variation: machine text tends toward uniform sentence lengths, while human writing is uneven. This pattern is often called burstiness.
- Stock AI phrases: recurring formulaic wording that language models produce far more often than human writers do.
- Hedging and transition words: heavy use of cautious qualifiers and connective phrases is a common AI tell.
- Em-dash density: machine-generated text tends to use em dashes at a much higher rate than typical human writing.
- Repetition: repeated sentence structures and restated ideas raise the score.
What the humanizer does
The humanizer also runs free in the browser. It is a cleanup pass, not a disguise:- Replaces stock AI phrases with plainer wording.
- Removes em dashes and invisible characters.
- Adds natural contractions.
- Marks sentences of uniform length so the writer can vary them.
How we evaluate quality
Because both tools are deterministic, in-browser utilities, evaluation is about checking the signal logic rather than chasing external benchmark scores. Our internal checks cover the basics:- Detection signals: known AI-written samples should score high, plainly human-written controls should score low, and mixed or heavily edited samples land in the middle.
- Humanizer output: stock phrases and em dashes are gone after a pass, contractions appear, and flagged uniform sentences are surfaced for the writer.
- Meaning preservation: a cleanup pass must not mangle the text. A rewrite that reads worse than the original is not a usable result.
- Regression history: changes to the detection signals or cleanup rules are logged so drift is visible over time.
What a score does and does not mean
A high AI score means the text shows several statistical signals common in machine writing. A low score means it does not. Neither is a verdict: your text, your edits, and each detector's current weights all differ from any test condition, and every detector in this space produces false positives, particularly on non-native English writing. Treat any score, ours included, as one input among many.What we do NOT claim
- No accuracy percentages or 'internal test' results presented as proof of performance.
- No model fingerprinting. Leap does not claim to identify which model wrote a text.
- No 'X% undetectable' marketing rates. Aggregate bypass percentages without a named corpus, date, and detector are unfalsifiable.
- No Turnitin numbers. Turnitin sells to institutions and offers no API an individual can license, so verified bypass rates for it cannot be independently checked.
- No 'zero false positives' guarantees. Every detector produces false positives, and every humanizer fails on some samples, including ours.
- No paid plans, credits, or word limits tied to unlocking the tools. Detection and humanization are free in the browser.
Comparisons on this site
Our /review and /vs pages describe what each product is for: GPTZero is a detector aimed at educators, Originality.ai targets publishers and content teams, Turnitin is sold to institutions, and various humanizers offer rewrite passes. These are neutral descriptions of purpose, not claims that Leap is more accurate. The fairest test of any tool is to run your own text through it.No-affiliate disclosure
Leap does not take affiliate revenue from any detector or humanizer linked anywhere on this site. We are not in the affiliate programs of GPTZero, Originality.ai, Winston, Copyleaks, Turnitin, or any humanizer. When a /review or /vs page recommends another product for a specific use case, that recommendation is not paid.How you can verify for yourself
You do not have to take any tool's word for it, ours included. The test takes about two minutes:- Run your text through Leap's free AI detector and note the score and the highlighted sentences.
- Run the same text through Leap's humanizer and review the cleanup it applies.
- Score the result with the detector you actually care about, whether that is GPTZero, Originality.ai, ZeroGPT, or whichever one will read your text downstream.