Isgen AI Review (2026): Pricing, Accuracy and Best Alternative

Isgen is a UK-based AI detector that advertises support for more than 80 languages and bundles plagiarism, humanizer, image and video tools. This Isgen AI review finds a broad toolkit held back by accuracy claims with no published method, a 2.5 out of 5 Trustpilot score and plans that split its tools, so Essai is our top pick.

Isgen suits multilingual users who want several checking tools under one login, and its paid plans start at $14 a month as of October 2026. The catch comes when you want its humanizer and its detector together: Ultimate, at $40 a month, is the only plan that includes both. Essai gives you a free AI detector and an AI humanizer in one web app, with both tools on every paid plan.

In our view, Essai is the best AI detector and AI humanizer for students and writers in 2026. This review draws on Isgen's public product, pricing, refund and privacy pages as of October 2026, its Companies House record, its Trustpilot page and published research on AI detection.

Isgen at a glance

Pros and cons

Pros

• Built for many languages. Isgen advertises AI detection in more than 80 languages, and its humanizer covers more than 60.
• A broad free toolkit. Free AI checks take up to 6,000 characters, and the image detector, video detector, AI Editor, grammar checker and citation generator cost nothing, as of October 2026.
• Sentence-level detail. Results split text into Human, AI and Mixed shares and highlight the sentences that push the score up.

Cons

• Accuracy claims without a method. Isgen quotes 96.4% accuracy on an unnamed benchmark, while a 2025 preprint that put it to work on Arabic articles recorded a 57% false-positive rate.
• Weak public reviews. Its Trustpilot profile shows 2.5 out of 5 from nine reviews, 78% of them one-star, and human writing labeled as AI is the most common complaint.
• Split plans. The paid humanizer and the AI detector share a plan only on Ultimate, at $40 a month. The $25 Writing plan leaves the AI detector out.
• Paywalled detail. Phrase-level analysis and what Isgen calls its "Advanced AI detector" are listed only on the Academic and Ultimate plans.
• A small free allowance. Free use stops at 12,000 words a month, according to Isgen's FAQ.
• A narrow refund window. Requests must come within 12 hours of subscribing, with fewer than 10,000 words used, and eligible yearly plans get only half their money back.
• Mixed messages on data. Isgen's pages describe text storage differently, and its privacy policy does not cover the text you submit.

Key features

AI detector

You paste text, upload a file or enter a URL, choose a language or let Isgen detect it, and run the scan. A Summary view shows Human, AI and Mixed shares, and a Detailed Analysis tab gives each flagged sentence an "AI Impact" score with color-coded highlights.

The limits matter here. Free checks stop at 6,000 characters, Academic raises the cap to 60,000, and only Ultimate removes it. Phrase-level analysis sits behind the Academic and Ultimate plans, and the pricing page marks the AI detector as not included on the Writing plan.

Plagiarism checker and bulk scan

Free plagiarism checks take 3,000 characters, Academic raises that to 20,000 and Ultimate to 30,000. You can limit the search to Google or Google Scholar results and get citations in styles such as APA, MLA and Chicago. Bulk scans of PDF, DOC and DOCX files, up to 10 MB each, are reserved for Academic (100 files per batch) and Ultimate (150 files).

AI humanizer and AI Editor

The Isgen AI Humanizer rewrites text in Basic or Advanced mode and a Formal or Adaptive style, in more than 60 languages, with a free limit of 3,000 characters per request. Heavier use requires the Writing or Ultimate plan. Because Writing leaves out the AI detector, Ultimate is the only plan with paid allowances for both rewriting and checking.

The free AI Editor needs no sign-up. You can import a DOCX file, check passages for AI, rewrite flagged lines and export the file with its formatting intact.

Image, video, grammar and citation tools

The image and video detectors work for free without an account, and the video detector caps free clips at 30 seconds and 200 MB. A free grammar checker handles up to 5,000 characters per check, a citation generator covers APA, MLA, Chicago, Harvard and other styles, and developers can reach the detector through an API listed on RapidAPI.

Privacy and data handling

Isgen's statements don't line up. The home page FAQ says Isgen stores no data apart from an input history for paid users that you can delete, while the plagiarism checker FAQ says uploads stay encrypted until your plan's document-history period ends (15 days on Academic, 30 on Writing and Ultimate).

The privacy policy, last updated February 10, 2024, says it was made with an online privacy policy generator. It does not address the text you submit, and it names the company "ISGEN LLC" rather than ISGEN LTD, the company on the UK register.

Isgen pricing (as of October 2026)

Isgen sells three paid plans with monthly or yearly billing. The US dollar prices below come from the Isgen pricing page as of October 2026; visitors in some countries see local currencies such as euros. Yearly billing is labeled "5 Months Free."

How Essai compares: Isgen pairs its paid humanizer with its detector only on Ultimate, at $40 a month or $288 a year. Essai includes both on every paid plan, starting with Basic at $14.99 a month, or $9.99 a month billed yearly, with unlimited AI detection, as of October 2026. Full details are on the Essai pricing page.

Billing and refunds

• Word allowances. Words reset each month and do not roll over. Paid subscribers can buy extra words, but the public pricing page does not list add-on prices.
• Refunds. The refund policy covers requests made within 12 hours of your first subscription with fewer than 10,000 words used, and refunds 50% of the price on eligible yearly plans. The pricing FAQ describes a different test, usage below 15% of your plan's maximum, so confirm with support before you buy.

Is Isgen accurate?

Isgen makes strong accuracy claims but publishes little you can check, and a 2025 study that ran Isgen directly recorded serious errors.

What Isgen says

Isgen's FAQ says the detector reached 96.4% accuracy on a benchmark where "the most used AI Detector tool in the market" reached 81.22%, and that its false-positive ratio is nearly zero. The FAQ does not describe the benchmark's texts, size or languages, and it does not name the rival tool.

The same FAQ concedes that no detector, Isgen included, is fully accurate. It also warns that a student who wrote most of a piece but followed an AI-suggested structure can still be flagged, because its models consider how an AI would organize a topic. And the pricing page reserves the "Advanced AI detector" for paid plans without explaining how it differs from the free checker.

What research found

• A direct test of Isgen. A 2025 preprint by Saleh Almohaimeed and colleagues (full text on arXiv), which the authors submitted to the Journal of Big Data, ran four commercial detectors on Arabic articles written by people and by 10 language models. Isgen recognized only 43% of the human-written articles as human, a 57% false-positive rate, and caught 53% of the AI-generated ones, for 48% accuracy overall.
• A risk for multilingual writers. Isgen's FAQ says AI text tends to have low "perplexity and burstiness," meaning predictable word choices and an even rhythm. A Stanford study published in Patterns (Liang et al.) found that seven popular detectors were near-perfect on essays by US eighth-graders but labeled, on average, 61.22% of TOEFL essays by non-native English students as AI-generated, as Stanford HAI reported. Isgen was not part of that study, but its pitch to multilingual users makes the finding hard to ignore.

Arabic appears on Isgen's own language list, and a 57% false-positive rate is a long way from the near-zero rate Isgen advertises, even if its models have changed since the preprint.

Essai's AI detector returns an AI probability score from 0 to 100% and works best on 150 words or more, and a free account lets you rescan as often as you need. In Essai's internal testing, our detector outperformed Isgen on many of the criteria we track.

Why does human writing get flagged at all? Our guide to AI detection false positives explains the causes, and teachers can follow this fair process for checking student essays before acting on any score.

What users say

Public feedback on Isgen is thin and mostly negative. As of October 16, 2026, the Trustpilot page for isgen.ai is unclaimed, displays the name "GEN.AI" and shows a TrustScore of 2.5 out of 5 from nine reviews, 78% of them one-star.

The complaints follow a pattern:

• Human work labeled as AI. Two reviewers say their own writing received a 100% AI rating.
• Image misfires. A third says the image detector labeled 3D artwork made in Blender and ZBrush as AI.
• Language gaps. One reviewer says the tool did not work for Dutch.
• Input limits. Another says a premium account's input limit forced them to split a small document into 20 parts.

What Essai users say

Essai users describe the difference in their own words:

"I've tested many alternatives, but nothing comes close to the quality Essai provides." (Priya Sharma, Essai user)

"Essai has greatly simplified my physics studies. The ability to humanize essays while keeping my original meaning intact has been incredibly helpful for my assignments." (Marcus Thompson, Essai user)

"Essai has revolutionized my business management studies. The text humanizer has significantly improved my reports and presentations. This all-in-one solution is a student's dream!" (David Williams, Essai user)

Isgen vs Essai

Isgen spreads its tools across three plans, so its paid humanizer and full detector only meet on Ultimate. Essai keeps both halves of the job together: an AI humanizer designed to keep your meaning while making phrasing, rhythm and word choice read naturally, and a free AI detector to check the result. Prices are as of October 2026.

Why Essai is the better Isgen alternative

• Both tools on every plan. Isgen keeps its paid humanizer on Writing and its full detector on Academic, and only Ultimate, at $40 a month, includes both. Every Essai paid plan includes both, starting at $14.99 a month as of October 2026.
• Unlimited detection. A free Essai account adds unlimited scans and detailed reports, and every paid plan includes unlimited AI detection. Isgen's free tier stops at 12,000 words a month and Academic at 350,000.
• Humanize and check in one place. Essai's humanizer and detector live in the same web app, so you can revise a draft and check it again in one workflow.
• A score you can read at a glance. Essai returns a single AI probability score from 0 to 100%, so you know where a draft stands before you submit or publish.
• A humanizer that keeps your meaning. Essai's humanizer is designed to make phrasing, rhythm and word choice read naturally, so AI-assisted text reads as human-written, and to help it pass popular AI detectors.
• Free to start. The humanizer's free tier handles up to 125 words per request with no signup and no credit card.

Best Isgen alternatives

• Essai: best overall. Our top pick for students and writers: a free AI detector with unlimited scans on a free account, plus an AI humanizer in the same app. Paid plans start at $14.99 a month, or $9.99 billed yearly, as of October 2026.
• Copyleaks: the closest match to Isgen on breadth, with AI detection in 30 languages, according to its documentation, and a plagiarism checker, but no AI humanizer. Paid plans start at $16.99 a month as of October 2026, and its Trustpilot score was 2.7 out of 5 from 365 reviews.
• GPTZero: a classroom-focused detector with a free plan of 10,000 words a month and no humanizer. Premium costs $23.99 a month, or $12.99 billed annually, as of October 2026, and its Trustpilot score was 2.1 out of 5 from 145 reviews.
• Originality.ai: a credit-based AI and plagiarism checker for publishers and editors. The free tier allows three AI scans a day of up to 2,000 words each, and its help center says it does not offer an AI humanizer.
• Winston AI: AI text and image detection for educators and publishers, with 16 languages listed for text detection. The free option is a 14-day trial with 2,000 credits, and paid plans start at $18 a month as of October 2026.

For the full ranking, see our guides to the best AI detectors and the best AI humanizers.

Verdict: our Isgen AI review

Isgen packs a lot into one account, from an AI detector aimed at more than 80 languages to plagiarism checks and free image and video detectors. The weak points are evidence and value: its accuracy figures come without a published method, a 2025 preprint recorded a 57% false-positive rate on Arabic text, its Trustpilot reviews repeat the same complaint, and you need the $40 Ultimate plan to get its paid humanizer and detector together. In our view, Essai is the best Isgen alternative in 2026 and our top pick overall. You get a free AI detector with unlimited scans on a free account, an AI humanizer designed to keep your meaning, and both tools on every paid plan from $14.99 a month, as of October 2026.