A Note on Bias Before We Start
Let's get this out of the way: we built SupWriter. This page is on our website. We have an obvious financial interest in you choosing our product. We're not going to pretend otherwise.
What we can promise is that every number on this page comes from controlled testing we conducted in March 2026. We used 200 AI-generated essays (ChatGPT-4, Claude, and Gemini) across five academic subjects. We ran each output through both tools, then tested against Turnitin, GPTZero, Originality.ai, Copyleaks, and ZeroGPT. You can replicate this test yourself — paste the same AI text into both tools and check the results. The numbers hold up.
With that said, let's talk about JustDone AI.
What JustDone AI Actually Is
JustDone AI is an all-in-one AI writing platform. It offers content generation, paraphrasing, summarization, and AI humanization. The idea is to be a Swiss Army knife — one subscription for everything AI-related.
In theory, that sounds appealing. In practice, the “everything tool” approach means nothing gets the deep engineering attention it needs. Their AI humanizer — which is what most people are comparing to SupWriter — uses relatively basic synonym replacement and sentence restructuring. It's a feature within a larger product, not a purpose-built solution.
And that shows in the results: 65% bypass rate across our test suite. That's better than QuillBot (42%) and Grammarly (48%), but it means roughly one in three pieces of content still gets flagged. If you're submitting an essay to Turnitin, those aren't odds you want to bet on.
The $2 Trial Problem
This is where JustDone AI's reputation takes a serious hit. They advertise a $2 trial prominently across their marketing. What many users don't realize until it's too late is that this trial auto-converts to a $39.99/month subscription after just 3 days.
Three days. That's barely enough time to test the tool properly, let alone make an informed decision. And the auto-conversion is buried in fine print that most people skip.
The result? Hundreds of Trustpilot reviews from users who got hit with unexpected $39.99 charges. Their Trustpilot rating sits at 2.1 stars, and the most common complaints are:
- “Charged $39.99 after I thought I canceled the trial”
- “No cancel button in the dashboard”
- “Customer support won't respond to refund requests”
- “Kept charging me months after I stopped using it”
These aren't isolated complaints. It's a pattern. Whether it's intentional dark patterns or just poor UX design, the outcome is the same: users feel tricked.
SupWriter's Approach: Transparent by Design
We built SupWriter as a response to exactly this kind of thing. Our pricing is $9.99/month. No $2 trial that auto-converts. No hidden fees. No difficult cancellation. You get 300 free words to test without even entering a credit card.
If you want to cancel, there's a one-click button in your dashboard. Hit it and you're done. No retention calls, no email chains, no dark patterns. We believe that if our product is good enough, people will stay. And they do — our retention rate speaks for itself.
That's not to say SupWriter is perfect. Our interface could be more polished. We don't offer the all-in-one feature set that JustDone does — no content generation, no summarizer. We do one thing. But we do it at 99%+ accuracy, and we charge a quarter of what JustDone charges.
Bypass Rate Breakdown: Detector by Detector
Let's get specific about the numbers, because “65% vs 99%+” doesn't tell the whole story. Here's how each tool performed against each detector:
Turnitin: JustDone passed 61% of the time. SupWriter passed 99.2%. This is the detector that matters most for students, and JustDone fails nearly 4 out of 10 submissions.
GPTZero: JustDone passed 68%. SupWriter passed 99.5%. GPTZero is commonly used by publishers and editors, so this gap matters for freelancers and content creators.
Originality.ai: JustDone passed 63%. SupWriter passed 99.1%. Originality.ai is the strictest commercial detector, and JustDone struggles significantly against it.
Copyleaks: JustDone passed 67%. SupWriter passed 99.4%. Copyleaks is increasingly used by enterprise clients and agencies.
The pattern is clear: JustDone performs inconsistently across detectors, hovering in the 61-68% range. SupWriter is consistent at 99%+ across the board. When you're paying for a humanizer, consistency matters more than anything.
Who Should Consider JustDone AI?
In fairness, JustDone AI isn't for the same user as SupWriter. If you want an all-in-one AI writing suite — content generation, paraphrasing, summarization, AND some humanization — and you're okay with a 65% bypass rate, JustDone offers breadth. It's a jack-of-all-trades.
But if your primary need is making AI text undetectable — which is why most people search for this comparison — then paying 4x the price for 34% worse performance doesn't make sense. And the billing practices alone should give you pause.
Our Recommendation
If you need reliable AI detection bypass: SupWriter. The 99%+ bypass rate at $9.99/month with transparent billing is, objectively, a better deal than 65% at $39.99/month with a $2 trial trap.
If you need an all-in-one AI writing platform and don't care about detection bypass: JustDone might work, but go in with your eyes open about the billing. Set a calendar reminder for day 2 of the trial.
If you're looking for alternatives to both, check out our JustDone alternatives page for a broader comparison.
Related Resources
- Best JustDone AI Alternative — Top alternatives ranked
- Grammarly vs QuillBot — Head-to-head comparison
- Best AI Humanizer Tools 2026 — Full market roundup
- Undetectable AI Alternative — Another popular humanizer compared
- NaturalWrite vs SupWriter — Similar comparison with test data