JustDone AI Review (2026): It Said "100% Undetectable". GPTZero Said 100% AI.

JustDone's AI humanizer isn't free, and in our test it didn't work. After three setup questions and about a minute of loading, JustDone told us our text was "100% undetectable now", then blurred the result and asked us to sign up and pay. When the HumanizerPRO team checked the rewrite it generated, GPTZero rated it 100% AI, Sapling 96.1% AI and ZeroGPT 62.1% AI. JustDone costs $19.99 a month, or $2 for a 7-day trial that renews at $29.99 a month, and purchases are non-refundable outside the EU. We rate it 3 out of 10. SuperHumanizer (free, no sign-up) and HumanizerPRO both passed all three detectors on the same text.

JustDone at a glance

What is JustDone?

JustDone, at justdone.com, is an AI writing platform designed for students. It combines more than 35 tools: an AI humanizer, AI detector, plagiarism checker, paraphraser, grammar checker, summarizer, citation tool, AI chat and a Chrome extension. It's run by GM Appdev Limited, a company registered in Limassol, Cyprus.

The humanizer is one of its main tools. JustDone says it "rebuilds sentence rhythm, adjusts tone, and removes AI patterns", lets you choose a tone, and shows Turnitin, Originality.ai and GPTZero logos under a "Double checked by" label.

How we tested JustDone

In September 2026, the HumanizerPRO team ran JustDone's humanizer on the same unedited GPT-4o text we use for every review: a 306-word post about a new blood test for biological age. Before humanizing, GPTZero and ZeroGPT both rated it 100% AI.

We pasted our text into JustDone's AI humanizer without an account and answered its setup questions, choosing the "Neutral & clear" tone, "Balanced" rewrite strength and "Optimize for every detector". Afterwards, we tested the rewrite on GPTZero, ZeroGPT and Sapling and compared it with the original.

One caveat: JustDone only shows the result blurred until you sign up and pay. We checked the rewrite JustDone generated and loaded on the page. We couldn't compare it with the unlocked version without buying a plan.

What happens when you click "Humanize"

Once you click "Humanize", JustDone asks three questions in a row: what tone you want, how strong the rewrite should be, and which AI detector to optimize for (Turnitin, Originality.ai, GPTZero or all of them). Next, progress messages such as "Analyzing tone & structure" and "Optimizing to Turnitin, Originality, GPTZero" flash on the screen. In all, the process took about a minute.

At the end, a box says "Humanized! Your text on 'Blood test age' is 100% undetectable now" over a blurred copy of the result, with an "Unlock Your Text" button. Clicking it opens a sign-up form, and the page states that JustDone is "an auto-renewing subscription service, billed at $19.99/month". The homepage's "Try AI Text Humanizer" button goes straight to the pricing page.

So despite promises like "no setup required", you can't get a humanized result from JustDone for free.

Does JustDone bypass AI detectors?

No, not in our test. GPTZero was "highly confident this text was AI generated" and rated it 100% AI, 0% human. Sapling rated it 96.1% AI. ZeroGPT gave it 62.1% AI, with a label saying it was "likely human written" but may include parts generated by AI, which most teachers wouldn't ignore.

That's a big gap from the "100% undetectable" message JustDone showed a few seconds earlier, before any detector had checked the text.

How good is JustDone's writing?

The rewrite was easy to read. It kept most of the key points: the test measures proteins in the blood, it can spot problems before symptoms appear, people can track how diet and exercise affect their biological age, and more studies are needed across different groups of people.

But it wasn't neutral, even though we picked "Neutral & clear". It opened with a blood test that tells us more "than just our birthdate", added lines like "The potential here is huge" and "This could truly transform the study of aging", and switched to "our blood" and "our bodies". It also turned "hundreds of proteins" into "a wide range of proteins" and dropped the name of the field, geroscience. The text we checked came back as one long paragraph instead of three.

For a blog post, it's acceptable after a little smoothing. For an essay or report, you'd need to adjust the tone.

JustDone pricing and plans

JustDone's pricing page showed these three plans in September 2026:

Every plan includes all 35+ tools. Keep in mind that the $2 trial renews at $29.99 a month, which is higher than the $19.99 monthly plan. JustDone's subscription terms say purchases are non-refundable unless a refund is required by law. If you're in the EU, you have a 14-day right to withdraw.

For comparison, HumanizerPRO lets you humanize 500 words without an account, and its paid plans start at $7 a month billed yearly, with a 3-day money-back guarantee. SuperHumanizer, our sister tool, is completely free.

JustDone pros and cons

What's good

• 35+ tools in one subscription, including a plagiarism checker and citation tool
• Tone and rewrite-strength options
• Readable rewrite that kept most of the key facts
• The annual plan is cheap per month if you use many of its tools

Downsides

• No free result: you must sign up and pay to see your text
• Called its output "100% undetectable", but GPTZero rated it 100% AI
• Failed Sapling (96.1% AI) and ZeroGPT (62.1% AI)
• Casual tone even with "Neutral & clear" selected
• The $2 trial renews at $29.99 a month, and purchases are non-refundable outside the EU

JustDone vs. SuperHumanizer vs. HumanizerPRO

On the same text, JustDone was the only one of the three that failed all three detectors. SuperHumanizer passed all of them and costs nothing, with no sign-up, 1,200 words per run, a Chrome extension and Android and iOS apps. HumanizerPRO passed all three too, lets you try it without an account, and includes a free AI detector and plagiarism checker, so you can check your text yourself instead of trusting a "100% undetectable" badge.

Is JustDone worth it?

Not for humanizing. You can't see a result unless you pay, and the one we tested didn't pass a single detector. If you're interested in JustDone's other tools, such as its citation tool or AI chat, the annual plan may be worth considering, but don't buy it for the humanizer.

If you need to humanize AI text, start with SuperHumanizer for free, or HumanizerPRO if you want tone presets and built-in checking. For more options, see our ranking of the best AI humanizers and why most free AI humanizers don't work.

Frequently asked questions

Is JustDone AI free?

No. JustDone's humanizer blurs the result until you create an account and choose a paid plan. The cheapest way in is $2 for 7 days, which renews at $29.99 a month unless you cancel at least 24 hours before the trial ends. SuperHumanizer is a completely free alternative with no sign-up.

Does JustDone bypass GPTZero?

Not in our test. GPTZero rated JustDone's rewrite 100% AI and was "highly confident this text was AI generated". Sapling rated the same text 96.1% AI and ZeroGPT 62.1% AI.

Does JustDone bypass Turnitin?

We weren't able to test this, because Turnitin is only available through schools and institutions. JustDone lets you "optimize" for Turnitin, but its rewrite failed GPTZero, Sapling and ZeroGPT in our test. Since August 2025, Turnitin also flags text it suspects was rewritten by AI humanizers.

Can I get a refund from JustDone?

JustDone's terms say all purchases are non-refundable unless the law requires a refund. EU customers have a 14-day cooling-off period to withdraw from the contract. To avoid being charged at the end of the $2 trial, cancel at least 24 hours before it expires.

Who owns JustDone?

JustDone is operated by GM Appdev Limited, a company registered in Limassol, Cyprus.

What is the best JustDone alternative?

SuperHumanizer is the best free alternative: it's 100% free, needs no sign-up and passed GPTZero, ZeroGPT and Sapling in our test. HumanizerPRO is the best paid alternative, with 500 free words without an account, plans from $7 a month billed yearly and a 3-day money-back guarantee.