What Undetectable.ai is
Undetectable.ai is built around volume and verification-by-testing. It offers batch processing for running many documents through at once, an API for plugging the rewrite step into someone else’s pipeline, and built-in checks against a named list of popular AI detectors, which is a big part of why agencies and content teams doing high volume use it: they want a single pass that produces a “passed” result across the tools their clients are likely to run.
Its marketing leans hard on that multi-detector testing as proof of effectiveness: rewrite the text, then immediately show it clearing several well-known detectors in the same session, and present that as evidence the output is undetectable.
Where NeverPrompted is built differently
NeverPrompted doesn’t run your text against a scoreboard of other companies’ detectors and report a pass rate, because a detector passing today tells you nothing about what that detector, or the next one, will do next month after it retrains on exactly the kind of output that beat it last time. Instead, NeverPrompted focuses on two things we can actually stand behind: reducing the concrete, human-legible AI tells in your sentence (stock phrasing, em dashes doing too much work, a flat unvarying rhythm) and checking, honestly, whether we can find a statistical watermark under the keys we hold.
Everything runs on your device. Nothing is uploaded to run a check or a rewrite, on any plan, which matters more the more sensitive the document is. And every rewrite is shown to you as a diff against your original wording, so you approve specific changes rather than accepting a wholesale replacement of your voice.
What neither of us can promise
Undetectable.ai’s own marketing advertises passing multiple named detectors as proof of “undetectable” output. That framing has a real gap: passing today’s public detectors says nothing about an AI provenance watermark, which isn’t a style pattern those detectors are even looking for. A watermark is a statistical signature the generating model itself embeds, and it is only checkable by whoever holds the key it was applied with, which is the model vendor and nobody else.
That means no tool, including NeverPrompted, can honestly guarantee that a document will evade an undisclosed vendor’s watermark, no matter how many public detectors it passes in a demo. We can tell you what we found under the keys we hold, and we can help you reduce the style signals a human reader or a classifier would notice. We won’t tell you either of those things adds up to a guarantee, because it doesn’t, and a tool that says otherwise is selling you a test result rather than a fact.
Wherever this page describes a result: a detected mark is not proof of authorship, and an absent mark is not proof of human authorship. NeverPrompted's on-device rewrite can reduce detectable evidence but cannot guarantee defeating a vendor's undisclosed watermark, on any tier.