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StealthWriter vs Undetectable AI

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. StealthWriter starts at $20, Undetectable AI at $9.99. Both have a free tier. Only Undetectable AI ships a public API.

Side by side

FactStealthWriterUndetectable AI
CategoryAI Detection & HumanizersAI Detection & Humanizers
Pricing modelFreemiumFreemium
Starts at$20 month$9.99 month
Public APINoYes
PlatformsWebWeb, API, Chrome Ext
CompanyAiVantage LLCUndetectable Inc.
Launched20232023
Last verifiedSep 6, 2026Sep 6, 2026

What our research says

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

Undetectable AI

Buy it only if you accept that passing a detector is a moving target: detector vendors retrain constantly, and text that cleared last month can flag next month. As a multi-format detection dashboard it is more defensible than as a bypass tool.

Pros

  • Detector and rewriter run in one pass, so you see which sentences changed and why
  • Coverage extends past text into image, voice, video and document classifiers
  • Browser extension works inside Docs and Gmail rather than a separate tab
  • Entry tier is genuinely cheap at annual rates

Cons

  • Rewrites often flatten voice and add filler to break statistical patterns
  • Detection on short passages is unreliable in both directions
  • Word quotas drain fast because rejected attempts still consume them
  • The free trial caps at 250 words, barely enough to judge output quality

Which one fits

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

Choose Undetectable AI if you need

  • Marketers cleaning up bulk LLM drafts before publishing
  • Editors wanting a second opinion on submitted copy
  • Teams screening images and audio for synthetic origin
  • Non-native writers smoothing register and tone

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