Quillify vs Undetectable AI: Honest Comparison (2026)
Both tools humanize AI text. But they're built for different people with different problems. Here's an honest side-by-side of what each does well — and where each falls short.
Deep Vyas
Founder, Quillify · Deep Technologies Inc., Vancouver BC
If you're comparing Quillify and Undetectable AI, you're already past the point of "is an AI humanizer worth using." You've decided yes. Now you need to know which one is right for your situation.
This is an honest comparison. I'm Deep Vyas, founder of Quillify, which means I have an obvious bias — but I also know both products well enough to tell you where Undetectable AI is genuinely better.
What Both Tools Do
Both Quillify and Undetectable AI take AI-generated text and rewrite it to reduce AI detection scores on Turnitin, GPTZero, and Originality.ai. Both use a language model for rewriting. Both have a web interface you paste text into and get humanized output from. The core use case is identical. Where they diverge is in who they're built for and what additional features they include.
Side-by-Side Feature Comparison
| Feature | Quillify | Undetectable AI |
|---|---|---|
| Free plan | ✓ 2,000 words/mo | ✓ Limited |
| Sentence-level AI scoring | ✓ GPT-2 per sentence | ~ Aggregate score |
| Multi-pass / Deep mode | ✓ 3-pass (Professional) | ✗ |
| Business writing modes | ✓ Email, Report, Proposal | ~ Generic "business" |
| APA 7 citation formatter | ✓ Full APA 7 + Word export | ✗ |
| Reference finder | ✓ 3 academic engines | ✗ |
| Plagiarism checker | ✗ | ✓ Built-in |
| Word export | ✓ With APA formatting | ✗ |
Where Undetectable AI Is Better
Plagiarism checking in one place
Undetectable AI includes a plagiarism checker alongside the humanizer. If you need both AI detection bypass and plagiarism verification in a single tool, Undetectable AI handles both without a second subscription. Quillify focuses exclusively on AI detection and humanization.
Browser extension
Undetectable AI has a browser extension that lets you humanize text directly in Google Docs and other web editors. Quillify is web-app only. If your workflow is heavily Google Docs-based, that's a real convenience advantage.
Where Quillify Is Better
Sentence-level detection scoring
Quillify shows you a GPT-2 perplexity score for every sentence before and after humanization. You see exactly which sentences are still flagging and why. Undetectable AI gives you an aggregate detection score. Knowing where the risk is lets you verify the rewrite worked before submitting.
APA 7 formatting and reference finder
If you're a student, Quillify is effectively two tools in one: a humanizer and an academic writing assistant. The reference finder searches three academic databases simultaneously, auto-inserts APA 7 citations, and exports a properly formatted Word document. Undetectable AI has no citation tools.
Business writing modes
Quillify's Professional plan has dedicated content type modes: Executive Email, Business Report, Client Proposal. Each applies a different tone register during the humanization pass. Undetectable AI has a "business" style option — a single generic setting rather than modes calibrated to specific professional formats.
Deep mode — three-pass humanization
Quillify's Deep mode runs three passes: pattern variation, register calibration, and a surgical final pass on sentences still above the AI probability threshold. For high-stakes submissions where you need to be below 10%, the multi-pass approach matters.
Which One Should You Choose?
Choose Quillify if:
- You're a student who needs humanization + APA citations + reference finding in one place
- You're a professional who needs business writing modes
- You want sentence-level AI scoring to verify the rewrite before submitting
- You need Deep mode for the lowest possible AI scores
Choose Undetectable AI if:
- You need a plagiarism checker alongside the humanizer
- You work primarily in Google Docs and want a browser extension
- You only need basic humanization without citation or academic formatting tools
Try Quillify free — 2,000 words/month, no credit card required: get started here. See the full plan comparison on the pricing page.
Frequently Asked Questions
Is Quillify better than Undetectable AI?
For students who need APA formatting and academic citations alongside humanization, Quillify is better — it's two tools in one. For professionals who need business writing modes, Quillify's Executive Email and Business Report modes produce more polished output. For users who primarily need a plagiarism checker or a browser extension for Google Docs, Undetectable AI has the advantage.
Does Quillify actually work on Turnitin?
Yes. Quillify measures GPT-2 perplexity sentence by sentence — the same signal Turnitin uses — and shows you the score before and after. Students using Quillify average a drop from 78% AI-flagged to under 10%. Deep mode runs a three-pass rewrite that achieves consistently lower scores than single-pass tools.
What is the price difference between Quillify and Undetectable AI?
Undetectable AI's entry plan starts at around US$10/month for 10,000 words. Quillify's Student plan is CA$19/month for 50,000 words, with APA 7 formatting, reference finding, and Word export included. For Canadian users, Quillify is priced in CAD with no currency conversion.
Can I try Quillify before paying?
Yes — Quillify's free plan includes 2,000 words/month of AI detection scoring and Quick mode humanization with no credit card required.
Try Quillify free
AI score, humanization, reference finder, and APA 7 export — all in one tool.
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