Paste an essay, blog post, or email and get a sentence-by-sentence AI score. Leap runs entirely in your browser: no signup, no word limit, and your text is never sent anywhere.
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What Leap's detector sees
Most detectors return a single 0-100 score. Leap scores text in your browser from writing signals and returns a score per sentence, so you can see exactly which passages look synthetic and which already read as human. That lets you edit surgically instead of rewriting the whole piece.
Sentence-level scoring
Each sentence gets its own 0-100 AI score, color-coded inline so the passages that weigh most are obvious at a glance.
Pattern explanation
Leap shows the specific signals behind your score: stock AI phrases, hedging and transition words, em-dash density, uneven versus uniform sentence length, and repetition, so you understand why a score landed.
How an AI detector works
AI-generated text tends to share statistical habits: a flatter vocabulary, sentences that are uniform in length, and predictable word choices. Detectors look for those habits. The two signals almost every detector relies on are perplexity, how surprising the next word is given the previous ones, and burstiness, how much sentence-to-sentence complexity varies. AI-generated text tends to have low perplexity and low burstiness. Human writers produce the opposite: occasional unusual word choices, and rhythms that swing between terse and elaborate.Leap combines these signals and scores each sentence independently. That matters because mixed human plus AI documents are common: a student who drafts with ChatGPT and then edits, or an editor who passes a human draft through an AI for polish. A single score smears those cases together. Sentence-level scoring shows you exactly which spans look AI-authored and which already read as human.Short inputs are hard for any detector. Under 50 words there is not enough signal to separate styles, and false positives climb. Treat a weak signal as a reason to be cautious, not as a verdict.
How Leap compares to other AI detectors
Here is how the major detectors students, teachers, editors, and content managers actually use differ in what they are for. Each is a neutral description, not a ranking.
Leap vs Quillbot's AI detector
Quillbot's AI detector ships bundled with its paraphraser and returns a single document-level percentage. Leap returns a sentence-by-sentence score and surfaces the specific signals behind it, so you can edit rather than guess.
Leap vs Turnitin's AI detection
Turnitin's AI detection runs inside institutional plagiarism workflows: students do not see the detector directly, teachers do, and there is no self-serve preview. Leap is a self-serve check you can run in your browser before submission.
Leap vs GPTZero
GPTZero pioneered the consumer AI detector category and is widely used by individual instructors. Leap is a free in-browser alternative focused on sentence-level scoring and pattern explanations.
Leap vs Copyleaks
Copyleaks is an enterprise plagiarism vendor that added AI detection to its content suite, built for bulk document processing. Leap is built for the single-document user who needs to see why a score landed.
Leap vs Scribbr and Sapling
Scribbr's AI detector is free and aimed at academic writing; Sapling's is tuned for business writing. Both return document-level scores. Leap focuses on per-sentence transparency.
Who uses an AI content detector?
Teachers and professors use AI detectors to spot submissions that may have been drafted by an AI tool. Most school policies do not ban AI outright; they require disclosure. A detector is a signal, not proof: a flagged paper is a reason to have a conversation, not an automatic fail. Sentence-level output helps that conversation, because "these three paragraphs look AI-authored" is a specific, discussable signal.Students use detectors to check their own drafts before submission. Legitimate human writing sometimes trips AI detectors, and formal academic tone has a lot in common with AI tone. Running your own draft through a detector before submitting gives you a chance to revise sentences that would otherwise look synthetic.Editors and publishers use detectors to triage freelance submissions, and content managers and SEO teams use them as a quick sanity filter before pages go live. Hiring teams sometimes check writing samples as one signal among many, never a sole reason to reject.
Flagged as AI? Clean it up.
Leap's humanizer is a free in-browser cleanup pass: it replaces stock AI phrases, removes em dashes and invisible characters, adds contractions, and marks sentences of uniform length so you can vary them. It does not guarantee passing any detector, but it makes the writing read more naturally.