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AI Undetect vs StealthWriter

Two fact sheets from our own research, side by side — pricing, platforms, API access and status re-checked by us rather than quoted from the vendors. AI Undetect starts at $5, StealthWriter at $20. Both have a free tier. Only AI Undetect ships a public API.

AI UndetectRewrites AI-drafted text to read as human and pass detector checks, with a built-in multi-detector scanStealthWriterRewrites AI-written text to read as human and scores it against detectors in the same pass

Side by side

FactAI UndetectStealthWriter
CategoryAI Detection & HumanizersAI Detection & Humanizers
Pricing modelFreemiumFreemium
Starts at$5 month$20 month
Public APIYesNo
PlatformsWeb, APIWeb
Company—AiVantage LLC
Launched—2023
Last verifiedSep 6, 2026Sep 6, 2026

What our research says

AI Undetect

It bundles rewriting and detector checks into one loop, which is the workflow people actually follow, and entry pricing is low. The catch is the category itself: detection engines retrain constantly, so passing today proves nothing about next month, and using it on academic work can breach integrity policies.

Pros

  • Free allowance to test output quality before paying
  • Detector panel shows results across multiple engines at once
  • Low entry price on annual billing
  • Rewrite API is documented for integration work

Cons

  • Effectiveness is a moving target as detectors retrain
  • The company behind the site is not identified anywhere on it
  • Word caps on lower tiers are easy to exhaust

StealthWriter

Pairing the rewriter with its own detector in one screen is the sensible design choice here — you can see the before and after score instead of pasting into a third tool to find out. The tiering is honest about what you are buying: daily rewrite count and input length, nothing hidden. Everything else about this category applies, though: detector scores are not a guarantee, the rewrite flattens voice and sometimes meaning, and using it on assessed work is a disciplinary matter regardless of what the score says.

Pros

  • Built-in detector scores text before and after the rewrite in the same interface
  • Free tier is a standing 10 rewrites a day, not a one-off trial
  • Every paid tier raises input length to 5,000 words, so tiers differ only by volume
  • Named US operator with published phone and email support hours
  • Changelog actively maintained, indicating ongoing development

Cons

  • Detector evasion degrades as detectors update — today's score is not a durable result
  • Rewriting flattens voice and can quietly alter facts or technical terms
  • $400/month top tier is steep for a single-function tool, and there is no API to justify it
  • Free tier's 1,000-word input cap excludes most real articles

Which one fits

Choose AI Undetect if you need

  • SEO and affiliate writers reworking AI drafts before publishing
  • Non-native English speakers smoothing machine-assisted prose
  • Teams that want rewrite plus detector check in one place

Choose StealthWriter if you need

  • Editing model-drafted marketing copy so it reads less mechanically
  • Checking a draft's detector score before it goes to a client who screens for AI text
  • Non-native writers polishing model-assisted drafts for tone

More comparisons

All AI Undetect alternatives →All StealthWriter alternatives →Browse all AI Detection & Humanizers →