Sapling's AI detector scores text token by token, so it can flag individual sentences as well as the document as a whole. It's a common pick for SEO teams, educators and moderators reviewing user-generated content. Sapling isn't part of the HumanizerEval benchmark yet; see the leaderboard for how popular humanizers, including StealthGPT, perform against leading detectors.
The detector
Sapling is a writing-assistant company founded by former researchers from Berkeley, Stanford, Meta and Google, best known for grammar and autocomplete tools for customer-facing teams. Its AI detector uses a Transformer model to estimate how likely each token in a text is to be machine-generated, then combines those scores into sentence-level and overall results. The free version checks the first 2,000 characters; Pro raises the limit to 100,000, and the detector is also available through an API, a Chrome extension and PDF or Word uploads. Sapling's September 2026 update specifically targeted humanized AI text.
Benchmark
HumanizerEval puts popular AI humanizers, including StealthGPT, through the same texts and leading AI detectors, and publishes every score. Sapling isn't in the panel yet. Check the leaderboard to compare how each tool performs.
Sapling describes its overall score as an estimate for the checked text, with sentence highlights scored separately. Those views support different parts of a review: the document result provides an overview, while highlights help locate individual passages. Use the sentence view to organize notes within the structure of the full draft.
Sapling’s evaluation guide recommends checking how much text was processed and inspecting extracted text from PDF or Word files. Extraction can change reading order, so the uploaded document and the text being analyzed deserve a side-by-side look. This is especially useful for documents with multiple columns or complex layouts.
Sapling scores sentence highlights separately from the overall result. Reading both views helps you connect an overview with the passages you want to examine.
Sapling recommends inspecting the extracted text and the amount processed. Compare the reading order with the original document before organizing your review notes.
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StealthGPT is built to make AI-written text read as human across leading AI detectors, including Sapling's sentence-level scoring. Sapling isn't part of HumanizerEval's benchmark yet, so we don't publish a bypass rate for it. See the HumanizerEval leaderboard for how popular humanizers, including StealthGPT, perform against leading detectors.
Sapling's AI detector uses a Transformer model, the same kind of system that generates AI text, to estimate the probability that each token was machine-generated. It combines those token scores into sentence-level and overall results, so it can highlight the specific sentences that look AI-written.
StealthGPT's AI humanizer rewrites AI generated content to introduce the structural variation, lexical diversity, and natural unpredictability that distinguish human writing from AI output. StealthGPT's AI humanizer is trained to target the specific signals each major detector uses and is continually updated as those detectors evolve.
StealthGPT is tested monthly in HumanizerEval, its open benchmark. Sapling isn't in HumanizerEval's detector panel yet; when it's added, this page will show StealthGPT's result.
See the HumanizerEval leaderboard for how StealthGPT and other popular humanizers perform against leading AI detectors, with every score published.
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