StealthWriter is an AI humanization tool designed to rewrite AI-generated text so it passes detection software. It offers three distinct modes: Ninja (the fast, lightweight model available on all plans including free), Ghost (a more aggressive rewriting engine for paid users), and Generator (available on Standard and Premium plans for deeper humanization).

The tool also offers 5 humanized models, 10 levels of humanization intensity, and 8 different writing styles. On paper, that's a lot of customization. There's a built-in AI detector so you can verify results before copying the output. And it supports sentence-level editing, letting you tweak individual sentences after the rewrite.

Here's the thing, though: StealthWriter's approach leans heavily on synonym replacement and sentence restructuring. It'll swap out words, rearrange clauses, and adjust phrasing. That works to a degree, but it's a fundamentally limited strategy. Modern AI detectors don't just look at vocabulary. They analyze deeper statistical patterns in your writing (perplexity, burstiness, token prediction sequences). The Perkins et al. (2024) study confirmed that basic paraphrasing reduces detector accuracy by only 17.4% on average. Tools that restructure deeper patterns push bypass rates much further. The question is where StealthWriter's ceiling sits. Let's get into the testing.

Let's talk about the money before the results, because the pricing has changed significantly from what some review sites report.

StealthWriter offers four tiers:

Free: $0, Ninja mode only, 300 words per request, daily limit of roughly 5,000 words. Good enough to test the tool, but you won't see StealthWriter's best results since Ghost and Generator are locked behind paid plans.

Basic: $20/month, unlimited Ninja mode plus Ghost mode access, 400 words per request. This is the entry point for serious use.

Standard: $35/month, 50,000 Ghost words per month, Generator access, 1,000 words per request.

Premium: $50/month, unlimited Ninja and Ghost, Generator access, 2,000 words per request, beta features, priority support, private Discord.

Annual billing gives roughly 2 months free (pay for 10, get 12). Some coupon sites advertise up to 30% off codes.

At $20-50/month, StealthWriter is not the budget option some older reviews suggest. For comparison, UndetectedGPT starts with a free tier and runs $19.99/month for the Starter plan, with a 96% bypass rate. You're paying more for a tool that, as we'll see, delivers significantly weaker results.

We don't play favorites. Every review follows the exact same process, and StealthWriter got no special treatment.

We started with a 1,000-word essay generated by GPT-5 on a standard academic topic. Nothing exotic, just a typical college-level argumentative essay. We ran the original through all five major detectors to confirm it scored in the high 90s for AI detection. Then we processed it through StealthWriter using their Ghost mode (the highest-quality rewriting available without going to the $35/month Standard plan).

The humanized output went through Turnitin, GPTZero, Originality.ai, Copyleaks, and ZeroGPT. We ran the test three times and averaged the results to account for any variance. Beyond the raw detection scores, we also evaluated readability and meaning preservation, because what's the point of bypassing a detector if your essay now reads like it was fed through a blender?

We also checked independent reviews from Originality.ai, EssayDone, AIDetectPlus, and BypassGPT. One systematic test at AIDetectPlus found that 4 out of 12 humanized texts (33%) still got flagged. That inconsistency pattern showed up repeatedly across reviewers.

StealthWriter's results land in what we'd call the "decent but not great" category. It clearly does *something*. Scores dropped across the board. But the drops weren't consistent enough to make us confident recommending it.

The highlights: ZeroGPT dropped to 18% and GPTZero came down to 20%. Those are legitimate passes. If those are the only detectors you're worried about, StealthWriter gets the job done. Copyleaks at 30% is borderline; some thresholds would pass it, others wouldn't.

The problem areas: Turnitin landed at 28%, which is higher than we'd like. Many institutions flag anything above 20-25%. And [Originality.ai](/blog/bypass-originality-ai-detection) at 38% is a clear fail: that's firmly in "AI-detected" territory. Independent reviewers confirm this pattern. One Originality.ai test found StealthWriter output received 100% AI score. Another found only an 18% Original (Human) rating. Originality.ai remains the toughest detector on the market, and StealthWriter's rewriting approach simply doesn't go deep enough to fool it.

The overall average bypass rate comes out to roughly 74%, which puts StealthWriter behind the top-tier tools. For a tool that starts at $20/month, that's a tough sell.

Let's give credit where it's due. StealthWriter isn't a scam (despite what some Trustpilot reviewers say). It's a legitimate tool that delivers partial results. The problem is that "partial" isn't good enough when your grade or professional reputation is on the line.

The Trustpilot situation is worth addressing directly: StealthWriter sits at 2.1-2.8 out of 5 across roughly 19 reviews. Multiple users report billing issues (being charged after cancellation, difficulty getting stored card information deleted). Customer support is effectively nonexistent, with emails reportedly going unanswered. On ProductHunt, it scores a more reasonable 4.1 out of 5, which suggests the tech-savvy crowd has a more positive experience than general users.

Here's the honest breakdown:

We built UndetectedGPT, so take this with whatever grain of salt you want. But we publish all our numbers, and the comparison speaks for itself.

Where StealthWriter averaged a 74% bypass rate, UndetectedGPT hit 96% across the same five detectors. That's not a marginal improvement: it's the difference between "might get flagged" and "consistently passes." On Turnitin, UndetectedGPT scored under 5% compared to StealthWriter's 28%. On Originality.ai (StealthWriter's weakest point), UndetectedGPT came in under 4%. Every detector showed a significant gap.

The meaning preservation issue is worth emphasizing too. StealthWriter's synonym-swapping approach occasionally changes what your text actually says. Independent reviewers noted that "the quality of the output makes it unusable at times, since it is riddled with grammatical and syntactically inaccurate content." UndetectedGPT works at the pattern level, not the word level, so your meaning stays intact while the statistical fingerprint changes.

The Perkins et al. (2024) study provides the academic context here. They found that basic paraphrasing (what StealthWriter essentially does at scale) reduced detector accuracy by about 17.4%. Dedicated humanization tools that target perplexity and burstiness simultaneously pushed bypass rates dramatically higher. That's the fundamental difference in approach.

And the price? $19.99/month for UndetectedGPT's Starter plan versus StealthWriter's $20/month Basic plan (or $35-50 for higher tiers). You're getting better results for less money, and there's a free tier to test before you commit. If you've been using StealthWriter and seeing inconsistent results (or if that Originality.ai score makes you nervous), it's worth running a free test to compare.