If you are replacing Isgen you want another detector, so this comparison is narrower and more direct than most. The deciding factors are usually four: what languages you write in, how much text goes through per scan, whether you need image detection, and what the output has to look like when you hand it to someone else. Isgen wins several of those outright.
Runs on /api/tools/score. Anonymous use gives 3 checks per day, pooled between the AI Detector and Document Detector, with input capped at 1,000 words. A free account gives 60 checks per day at 5,000 words, kept in history. Starter allows 200 per day, Pro and above are unlimited. Minimum input is 25 words. Results band at under 30 for likely human-written, 30 to 69 for mixed signals, 70 and above for likely AI-generated.
Paste some text or load the example to estimate AI likelihood.
This section is not a formality. On several measurable points Isgen is ahead of us, and if any of them is your priority you should stay.
Languages. Isgen states that its AI Content Detector supports "over 80 languages" and lists them individually, from Portuguese and Ukrainian through to Tamil, Uzbek and Xhosa (isgen.ai, checked 16 August 2026). TextSight's detector is English-only. It is an ensemble of DeBERTa, RoBERTa and ELECTRA, and it carries a known false-positive bias against writers who learned English as a second language. If your text is not in English, or if you are an ESL writer who has been wrongly flagged before, Isgen's multilingual models are a real and material advantage. We would rather lose the sale than have you discover that afterwards.
Volume per scan. Isgen's feature comparison lists a ceiling of 60,000 characters per AI detection scan on both the Academic and Ultimate tiers (isgen.ai/pricing, checked 16 August 2026). Our marketing paste box caps at 5,000 words for a free account. If you routinely check whole dissertations in a single pass, that gap matters.
Word allowances. Academic at $8 per month billed annually lists 350,000 detection words per month, and Ultimate at $24 per month billed annually lists unlimited words (isgen.ai/pricing, checked 16 August 2026). Both also list "Unlimited calls per day".
Image detection. Isgen lists an AI Image Detector among its tools (isgen.ai, checked 16 August 2026). TextSight does not detect AI-generated images at all. If part of your job is checking submitted images, nothing in this comparison replaces that.
Bulk and shareable reports. Isgen's comparison table lists 100 bulk AI scans on Academic and 150 on Ultimate, plus "Shareable Report" and "Downloadable Report" on all three tiers, with 15 days of document history on Academic and 30 days on Ultimate and Writing (isgen.ai/pricing, checked 16 August 2026).
Two claims on Isgen's site should be read as the company's own statements rather than as independent findings: "isgen boasts an accuracy of 96.4% on a benchmark where the most used AI Detector tool in the market has an accuracy of 81.22%", and "Our AI Detection tool provides a false positive ratio of nearly 0%" (isgen.ai, checked 16 August 2026). Those are vendor figures on a benchmark the vendor selected. We publish no accuracy figure of our own, because no shared public benchmark exists that would make one comparable, and a single number tends to hide the false positive question rather than answer it.
Neither of these is a criticism, but both surprise people.
First, the tiers are not a ladder. Isgen's own feature comparison marks the $15 Writing tier as "AI Detector: No" and "Plagiarism Checker: No", while the cheaper $8 Academic tier marks both "Yes" (isgen.ai/pricing, checked 16 August 2026). Writing is a humanizer and proofreading tier that happens to cost more, not an upgrade over Academic for detection. Its detection scan ceiling is also 6,000 characters against Academic's 60,000 (same page and date).
Second, the refund condition is specific. Isgen's FAQ states: "If your account's usage falls below 15% of the maximum allowed under your chosen plan, you can submit a refund request" (isgen.ai/pricing, checked 16 August 2026). The same FAQ states that unused words do not roll over month to month.
All figures read from vendor pages on 16 August 2026. Blank means the vendor does not publish that number.
| Tool | Detection scope | Verified price | Verified detection limits | Source |
|---|---|---|---|---|
| Isgen | Text detector, over 80 languages stated, plus an AI Image Detector | Academic $8, Writing $15, Ultimate $24 per month, billed annually ("Save 40%" yearly toggle) | Academic 350,000 words/mo, 60,000 chars per scan, 100 bulk scans, 15 day history. Ultimate unlimited words, 150 bulk scans, 30 day history. Writing: no AI Detector | isgen.ai/pricing, isgen.ai |
| Smodin | Detector inside a full writing suite; homepage states "Languages 100+" | Starter $12.99/mo or $10/mo annually; Premium $19.99/mo or $16/mo annually | Premium adds bulk processing, API access and a Chrome extension | smodin.io/pricing, smodin.io |
| Netus AI | Detector inside an 18 tool suite; "36 languages support" | Free $0, Basic $14, Standard $30, Premium $59, Elite $99 per month | Free tier lists "AI Detector - unlimited usage" | netus.ai/pricing |
| Monica | Detector inside a general AI assistant; combines GPTZero, Copyleaks and ZeroGPT per its own page | Not quoted (see note) | Detector paste box capped at 250 words; page states "2 detectors are locked. Upgrade to unlock" | monica.im/tools/ai-content-detector |
| TextSight | English-only ensemble detector, text and documents | Starter $9.99 ($7.49 annual), Pro $19.99 ($14.99), Business $39.99 ($29.99), Enterprise $79.99 ($59.99) | Anonymous 3 checks/day at 1,000 words; free account 60/day at 5,000 words; Starter 200/day; Pro and above unlimited; minimum 25 words | textsight.ai |
Note on Monica pricing: Monica's plan prices are not present in its own published pricing page, so we do not quote a figure. Check monica.im/pricing directly.
Stay on Isgen if you check non-English text, need image detection, scan very long documents in one pass, or rely on bulk scanning and shareable reports. On those four points it is ahead of everything else here.
Try Smodin if you also need plagiarism checking and translation from the same subscription. Its Starter tier at $12.99 per month lists the AI Content Detector alongside a plagiarism checker, translator, rewriter and writer (smodin.io/pricing, checked 16 August 2026).
Try Netus AI if you want unlimited detector usage at zero cost as a permanent fallback. Its free plan carries that explicitly (netus.ai/pricing, checked 16 August 2026), though the rewriting side of the free tier is capped at 500 words per month.
Try Monica only if detection is a small part of a much larger assistant workflow. Its paste box takes 250 words per check and its own detector page says two of its three integrated engines are locked until you upgrade (monica.im/tools/ai-content-detector, checked 16 August 2026).
Try TextSight if your work is in English and you want the detection output to be defensible rather than just a number. Concretely, that means sentence-level analysis from Starter upward so you can see which passages drove the score, PDF export from Starter upward, file upload, URL scan and bulk scan, a Chrome extension and a REST API from Pro upward, and teams with branded reports from Business upward. Our bands are deliberately conservative: 30 to 69 is reported as mixed signals rather than forced into a verdict.
Being blunt about the trade: you are giving up more than 79 languages, image detection, and a much larger per-scan ceiling. Take that seriously.
All pages read directly from the vendor's own live site on 16 August 2026.
The deeper head-to-head: feature table, where GPTZero wins, where TextSight wins, and migration steps.
Read the comparePerplexity, burstiness, and transformer scoring explained, so you can read any detector's verdict critically.
Read the guideWhy detectors over-flag ESL and formal writing, and how sentence-level evidence helps you defend real work.
Read the guideThe full ranking with detection approach, pricing, and use-case fit side by side.
See the rankingStart with TextSight's free tier. No card, no signup, no commitment. Your first scan in about six seconds, with the evidence shown line by line.