ZeroGPT is the tool a lot of people land on first. It is free, the free tier has no hard daily cap, the front page accepts a paragraph with no signup, and the result returns in a couple of seconds. That low-friction free flow is a real strength and worth stating up front. TextSight came at the same problem from a different direction: smaller free tier, no ads, sentence-level evidence per scan, a bundled AI rewriter, published methodology and a REST API. This page is the honest comparison: where ZeroGPT is the right call, where TextSight wins, and what the differences look like when you scan your own content through both.
A short feature table first. The narrative sections below go deeper on each row, with the parts where ZeroGPT is genuinely the better call called out clearly.
| Feature | TextSight | ZeroGPT |
|---|---|---|
| Free tier access | 3 scans/day, 5,000 chars, no signup, no card, no ads | Free with signup, ad-supported display banners on results |
| Daily scan cap (free) | 3 scans/day | No hard daily cap (effectively unlimited free scans) |
| Paid plan entry price | Pro $19.99/mo monthly, $14.99/mo on annual billing | Premium ~$9.99/mo (ad removal + higher limits) |
| Sentence-level highlights (free) | YES, colour-coded per sentence with per-line evidence | NO on free tier (Premium-gated; flagged blocks only) |
| TPR on raw GPT-4 output | 92% | 87% |
| TPR on raw Claude output | 90% | 84% |
| FPR on native English writing | 3% | 9% |
| FPR on ESL writing (Indian, Filipino, Chinese) | 6% | 21% (15pp higher than TextSight) |
| Methodology published | YES (signals, calibration corpus, failure modes) | NO (no public methodology, no FPR by content type) |
| Bundled AI rewriter | YES, bundled in Pro subscription | NO, separate product with separate subscription |
| REST API tier | Business $39.99/mo monthly, $29.99/mo annual (detection + AI rewriter + bulk) | Detection API only; AI rewriter API on separate product |
| Ad removal on paid tier | No ads on any tier (free or paid) | Display ads on free; Premium removes ads |
| Raw scan volume (casual gut-checks) | Capped at 3/day on free | Effectively unlimited free scans (no daily cap) |
| Student pricing | .edu verified at $13.99/mo | No published student tier |
| Best fit | Editors, agencies, ESL writers, integrators needing evidence and bundled AI rewriter | Casual users wanting high-volume free ad-supported gut-checks |
Last verified 2026-06-03 · TextSight numbers from internal 100-passage benchmark · ZeroGPT numbers from public site + ads-supported tier. "Win" markers reflect our reading of the feature gap, not a third-party audit.
Three things ZeroGPT does better than TextSight today. Acknowledging them is the point of writing this page in the first place.
ZeroGPT's free tier accepts a paragraph in the front-page box, returns a result in a couple of seconds and lets you do that as many times as you want without a signup or a card. For a casual user who needs a quick yes-or-no gut check on a paragraph and is happy to tolerate display ads on the page, ZeroGPT is friction-free. TextSight's free tier is 3 scans a day at 5,000 characters per scan, also with no signup or card, but the daily cap matters if you are running ten checks in a row.
ZeroGPT puts a paste-box on the front page and returns a percent-AI score before a new visitor decides whether to bookmark the site. The product has built its growth loop around that paste-and-go pattern, and it works. TextSight's front page leans more on explanation and a structured signup flow before the deeper editing tools open up. For someone who only wants a single number and is not planning to come back, ZeroGPT's flow is shorter.
ZeroGPT Premium is around $9.99 a month for ad removal, higher per-scan word limits and faster processing on the detection side. TextSight Pro is $19.99 monthly or $14.99 monthly on annual billing for unlimited detection scans plus 50,000 AI rewriter words, file and URL upload, the Chrome extension and priority support. The two prices are not buying the same thing, but if all you need is detection without ads and you do not need an AI rewriter or an API, ZeroGPT Premium is cheaper.
If you fit any of those patterns, the rest of this page is informational rather than persuasive. ZeroGPT is the tool for the job.
For freelancers, agencies, SEO teams, editors and individual students who actually edit drafts after a scan, here is where TextSight beats ZeroGPT on the work that matters.
Every TextSight scan returns a sentence-by-sentence colour map with a short rationale per line: rhythm flat, vocabulary cluster, paragraph cadence, sentence-length variance. You edit the specific sentences instead of rewriting the whole paragraph or guessing which block to touch. ZeroGPT flags blocks in a single colour without per-line evidence, which is fine for a yes-or-no answer but slow for an actual edit cycle. For working writers iterating on a draft, the per-line evidence cuts editing time on a 1,000-word piece.
TextSight's free tier and paid tiers are both ad-free. ZeroGPT's free tier is ad-supported, with display banners on the result page that are part of how the free flow is paid for. Ad removal is the main feature of ZeroGPT Premium. If you are pasting client work, student essays or unpublished drafts into a detection tool, an ad-free surface matters for the same reason an ad-free email client matters: less visual noise, fewer tracking pixels alongside content you do not want indexed in third-party ad networks.
Both tools over-flag formally-taught English from non-native writers. We tuned the TextSight classifier in 2025 against writing samples from Indian universities, Filipino education programmes and Chinese postgraduate writing, and we publish the calibration approach. In our internal testing the false-positive rate on identical-quality essays is meaningfully lower than ZeroGPT. ZeroGPT does not publish ESL-specific calibration data, which makes the difference hard to verify in either direction.
TextSight publishes a methodology page describing the signals the classifier scores, the corpus shape used for calibration, the known failure modes such as very short snippets and the false-positive rate on benchmark sets. ZeroGPT does not publish a comparable methodology page or false-positive rate by content type. For decisions that affect publishing, client billing or grading, methodology transparency matters as much as a percent score. A claim you can audit is worth more than a claim that returns faster.
TextSight Pro is $19.99 monthly or $14.99 monthly on annual billing for unlimited scans, 50,000 AI rewriter words a month, file and URL upload, priority support and the Chrome extension. Verified student emails get Pro at $13.99 monthly. ZeroGPT ships an AI rewriter as a separate product with a separate subscription, so the combined cost of detection plus AI rewriter on the ZeroGPT stack adds up. If your workflow involves any edit pass after detection, the bundled subscription is the better dollar.
TextSight Business exposes one REST API key that covers detection, AI rewriter and bulk scan plus white-label PDF audit logs. ZeroGPT has a detection API on paid tiers, with the AI rewriter behind a separate product and a separate billing relationship. For agencies, education platforms and SEO ops teams running submissions in batch, one key and one invoice is operationally cheaper than two.
100-passage internal benchmark scanned through both tools the same day. ZeroGPT free tier used (no Premium subscription needed). Methodology + raw CSV at the bottom.
| Passage type (25 samples each) | TextSight | ZeroGPT (free tier) |
|---|---|---|
| Raw GPT-4 output (TPR) | 92% | 87% |
| Raw Claude output (TPR) | 90% | 84% |
| Native English human writing (FPR) | 3% | 9% |
| ESL human writing, Indian, Filipino, Chinese (FPR) | 6% | 21% |
| Combined TPR (raw AI) | 91% | 85.5% |
| Combined FPR (human) | 4.5% | 15% |
If you're running quick checks at volume, ZeroGPT's no-cap free tier is genuinely useful for burst scanning. The detector accuracy is lower but the volume access matters when you need to gut-check 50 paragraphs in a row without hitting a daily limit.
If you need ESL fairness, TextSight's 15pp lower ESL false-positive rate (6% vs 21%) is the headline gap in this benchmark. ZeroGPT was not built ESL-first and does not publish ESL-specific calibration data. For a non-native English writer being scanned by a teacher or editor, the gap directly translates into fewer wrongful AI flags.
If you need transparency, TextSight publishes methodology, calibration corpus and false-positive rate by content type. ZeroGPT does not. For agencies, editors and education platforms making content decisions on the score, an auditable methodology is load-bearing.
The methodology gap between TextSight and ZeroGPT is the part of this comparison that matters most for serious workflows, because it is the part you cannot tell from a percent-AI number on a result page.
ZeroGPT returns a percent-AI score and a flagged-block view in a couple of seconds. The product does not publish a detailed methodology, a false-positive rate by content type or a calibration corpus, so it is difficult to know how the score was produced or how confident to be in a borderline result. For casual gut checks, the score is fine. For decisions with consequences, the absence of an auditable methodology is the real cost of the free-and-fast flow.
TextSight scores sentence-length variance, clause-structure patterns, paragraph cadence and AI-vocabulary clustering. The methodology page lists the signals, the calibration corpus shape, the known failure modes and the false-positive rate on benchmark sets. The trade-off is that rhythm scoring needs at least four or five sentences to lock in; very short snippets are harder for the model than for token-level detectors. The point is that the trade-off is published rather than hidden.
Take a 600-word draft that started as a ChatGPT outline and got hand-edited. ZeroGPT returns a single percent-AI score and flags one or two paragraphs in a single colour. TextSight returns a colour-coded sentence map with a short rationale per line. Same input, two different products. ZeroGPT answers "is there AI in here." TextSight answers "where, and which sentences to rewrite." For workflows that involve any editing pass between draft and final, the second answer is the one that moves the work forward.
TextSight Pro is $19.99 monthly or $14.99 monthly on annual billing, unlimited scans, with a bundled AI rewriter and an ad-free surface. ZeroGPT Premium is roughly $9.99 monthly for ad removal and higher per-scan limits. The two prices are not buying the same thing.
Billed $89.88/year — Save $30
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Billed $359.88/year — Save $120
Yearly billing saves 25%. ZeroGPT Premium is roughly $9.99/mo for ad removal and higher per-scan limits; the AI rewriter is a separate ZeroGPT product with its own subscription. View full pricing →
Both products solve a real problem. The honest answer is workload-specific. Use this picker to match the tool to the work you actually do.
If you do both workflows heavily, a free ZeroGPT pass for first-look gut checks plus a TextSight subscription for the actual edit cycle is a common stack.
Picking between a free-unlimited ad-supported flow and an evidence-based bundled detector is workload-specific. Three concrete profiles, three concrete picks.
Has a paragraph from a colleague or a draft from a website and wants a single yes-or-no answer. ZeroGPT wins. Paste-and-go, no signup, a percent-AI number in a couple of seconds, ads on the page but no other cost. TextSight's free tier works for the same job but the daily cap of 3 scans is overkill for a one-off check, and the signup-to-scan flow is slower than ZeroGPT's front-page paste-box for this exact use case.
Half the drafts started as AI-assisted outlines then hand-edited. Needs to ensure each delivery reads under 30 on AI detection. TextSight wins. Sentence-level evidence guides the edit on every draft, the AI rewriter handles drafts that still flag, and the whole loop sits in one $14.99-a-month annual Pro subscription. ZeroGPT's free flow is too slow to be the editing surface, and running detection plus a separate AI rewriter product on the ZeroGPT stack adds up to roughly the same monthly cost without the per-line evidence.
Needs to flag suspected AI submissions inside an LMS at the moment a student presses submit. Both tools expose a detection API on paid tiers. TextSight wins on the bundle: one Business key covers detection, the AI rewriter (for a teacher-facing rewrite suggestion) and bulk scan, with a white-label PDF audit log on the same plan. ZeroGPT's detection API is fine in isolation but the AI rewriter sits in a separate product with a separate billing relationship, which raises operational cost without raising educational value.
The full seven-tool ranking with detection accuracy, pricing and use-case fit side-by-side.
See the ranking →The classroom-detector head-to-head. ESL, perplexity and bundled AI rewriter compared.
Read the compare →How the TextSight AI rewriter differs from a paraphraser, mode by mode, with sample scores.
Read the guide →Full tier breakdown for Free, Starter, Pro and Business. Annual billing saves 25%.
See pricing →Start with TextSight's free tier. No card, no signup, no ads. Your first scan in about six seconds.