Undetectable.ai is one of the most recognized brand names in the AI rewriter category. The product was built and marketed around rewriting AI text so it slips past common detectors, and a detector view was added later mainly to validate the AI rewriter's own output. TextSight comes at the same problem from the other direction. The detector is the centre of the product, with sentence-level highlights and a published methodology, and the AI rewriter is bundled for the pre-publish calibration workflow rather than as the headline score-reduction feature. This page is the honest comparison: where Undetectable is the better pick, where TextSight wins, and how the two products map to different jobs to be done.
A short feature table first. The narrative sections below go deeper on each row, with the parts where Undetectable is genuinely the better call called out clearly.
| Feature | TextSight | Undetectable.ai |
|---|---|---|
| Primary product | Detector-first with bundled ethical AI rewriter | AI Rewriter-first with score-reduction focus; detector secondary |
| Detector accuracy / scope | Real impartial detector on arbitrary writing, published methodology | "Detector" exists to validate its own AI rewriter output (proxy, not impartial classifier) |
| Sentence-level evidence | Yes — colour-coded per sentence with per-line rationale (rhythm, vocabulary, cadence, length variance) | No — UI does not surface per-sentence detector signals |
| ESL false-positive rate (Indian/Filipino/Chinese student writing) | ~6% (TextSight internal benchmark, 600 ESL essays, verified) | Not publicly tested for ESL (their AI rewriter rewrites whole doc anyway) |
| Free tier | 3 scans/day at 1,500 words per scan, permanent, no signup for first scan | Limited free credits gated behind signup |
| Pro monthly price | $19.99/mo flat (or $14.99/mo on annual billing) — bundled detection + AI rewriter | Starts ~$9.99/mo then scales with usage (word allowance pricing) |
| .edu student discount | $13.99/month (verified .edu email) | No published .edu rate |
| Pro annual effective price | $14.99/month flat ($179.88/year, predictable) | Steep annual discount on AI rewriter-only allowances; effective rate roughly half of monthly |
| AI Rewriter aggression levels | 3 modes (Light / Balanced / Maximum) — all rhythm-aware | 3-4 aggression levels — no "preserve voice" mode |
| Voice / cadence preservation | Yes — authentic-voice calibration, preserves source vocabulary and citations | No — Maximum mode willing to break source voice to drive scores to zero |
| Ethical scope / framing | Authentic-voice calibration for pre-publish editing | Explicit score-reduction framing in product name and marketing |
| TextSight catch rate on Light Undetectable output | 82% (TextSight detects most Light-mode rewrites) | Light mode (Undetectable claims 95% pass rate on its own loop) |
| TextSight catch rate on Balanced Undetectable output | 71% (TextSight still catches majority) | Balanced mode |
| TextSight catch rate on Maximum Undetectable output | 58% (arms race is real — Maximum gets past detection ~42%) | Maximum mode is the most aggressive in the category |
| Best fit | Client work, grant applications, academic submissions, editorial pre-publish calibration | SEO content at scale, raw score-reduction need where score-to-zero is the only metric |
Prices, features, and benchmark numbers reflect our internal testing + Undetectable.ai's public pricing as of . Undetectable.ai is an AI rewriter-first product; its bundled detector validates its own rewrites rather than scoring arbitrary writing, which is why this page frames the two tools as solving different jobs. "Win" markers reflect our reading of the feature gap, not a third-party audit.
Four things Undetectable does better than TextSight today. Acknowledging them is the point of writing this page in the first place.
Undetectable.ai has been shipping an AI rewriter-centred workflow since 2023 and the focus shows. The rewrite engine, the multi-pass aggression slider, and the Chrome extension are polished in the way that only a singularly-focused product team delivers. TextSight ships a competitive AI rewriter inside a broader detect-plus-rewrite workflow, but the depth Undetectable has built on the rewrite surface specifically is genuinely deeper.
This is the core reason most users pick Undetectable, and it is not marketing. On their Maximum mode the AI rewriter runs multiple rewrite passes and is willing to break voice and cadence to drive scores toward zero on a basket of common detectors measured by the company itself. For a workflow where the only metric is a low score on a target detector, the multi-pass approach delivers. TextSight's single-pass rhythm rewrite trades a few points of score reduction for output that still reads like the source writer.
"Undetectable.ai" is one of the most searched AI rewriter brand names in writing forums and freelance groups. If a client or editor asks which AI rewriter you use, brand recognition is real marketing value. TextSight is younger and competes on substance and bundle math rather than name recall. For solo writers whose buyers already know the name, the recognition shortcut matters in the sales conversation.
Undetectable's annual billing is the most aggressive in the category, with effective monthly rates dropping by roughly half on a year commitment. For users who can prepay a year and only need an AI rewriter, the annual per-word math is competitive with TextSight Starter and beats TextSight on raw AI rewriter credits. The commitment risk is the catch, but for predictable high-volume workflows the annual plan wins on cost.
If you fit any of those patterns, the rest of this page is informational rather than persuasive. Undetectable is the tool for the job.
For freelancers, agencies, SEO teams, editors, and individual students pre-scanning their own English drafts, here is where TextSight beats Undetectable on the work that matters.
Undetectable's bundled detector exists to validate the AI rewriter's own output. It tends to clear content that other detectors still flag because the two are tuned together. TextSight's detector is the centre of the product, tuned to score arbitrary writing honestly, with a published methodology. For a writer running a calibration check before publishing, an SEO lead auditing a contributor's draft, or a teacher evaluating a student essay, an independent detector is what you actually need, not a validation loop on a rewriter's output.
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 draft. Undetectable returns a confidence score and a rewrite, which is useful for the score-reduction workflow but not for the editing workflow. For working writers iterating on a draft, the per-line rationale cuts editing time roughly in half on a 1,000-word piece compared to a score plus a wholesale rewrite.
Detectors built on perplexity tend to over-flag formally-taught English from non-native writers and casual first-person blog voice because both patterns have lower-than-average word predictability. Undetectable's detector is not primarily tuned for ESL accuracy, since the detector exists mainly to validate the AI rewriter's own output. TextSight's rhythm scoring weights structural variance, which separates cleanly from vocabulary choice. In internal testing on Indian, Filipino and Chinese student writing plus first-person blog drafts, TextSight's false-positive rate is roughly 25 to 35 percent lower than perplexity-led detectors on identical-quality content.
Undetectable's free path is a small preview gated behind email signup, with meaningful use requiring a paid plan. TextSight's free tier is 3 scans a day at 1,500 words per scan, permanent, no card and no signup for the first scan. For ongoing evaluation, occasional student use, or freelancers between drafts, the permanence is the real differentiator. On the paid side, verified .edu emails get TextSight Pro at $13.99 monthly, a price point Undetectable does not match.
"Undetectable.ai" leans into score-reduction framing in its name and marketing. That resonates in writing communities but creates awkward conversations in academic and enterprise settings where a buyer has to defend the choice to a dean, a compliance lead, or a procurement committee. TextSight positions as a detection and rewrite workflow tool with a published Authenticity Score, which is easier to defend in compliance and editorial contexts. Both tools can be used ethically. The brand framing is what differs, and it matters more in some buying contexts than others.
Undetectable.ai is not designed as an honest detector — its detection function exists to validate its AI rewriter's own output, not as an impartial classifier. So a head-to-head TPR/FPR table is fundamentally misleading. What we CAN measure is whether TextSight detects raw Undetectable.ai-rewritten output.
| Undetectable mode | n | TextSight detection rate | What Undetectable claims about its mode | Read |
|---|---|---|---|---|
| Light | 50 | 82% detected by TextSight | Lightest rewrite pass; Undetectable claims ~95% pass rate on its own loop | TextSight catches most Light-mode rewrites |
| Balanced | 50 | 71% detected by TextSight | Moderate aggression; default for most paying users | TextSight still catches majority |
| Maximum | 50 | 58% detected by TextSight | Aggressive multi-pass rewrite; willing to break voice to drive scores to zero | Maximum gets past detection ~42% — arms race is real |
| Combined (all modes) | 150 | ~70% mean detection rate | 3 aggression levels tested | TextSight catches 7-in-10 AI rewriter rewrites on average |
The honest read: The detection arms race between AI rewriters and detectors is real and ongoing. Undetectable's Maximum mode is genuinely aggressive — it gets past TextSight 42% of the time. Most modes (Light + Balanced) are caught at 71-82%. No single tool gives you 100% certainty either way.
For agencies running editorial review — TextSight + ESL-aware writers writing in their own voice is still the safest combination. The lower-aggression Undetectable modes (where most users actually operate, because Maximum mode breaks too much voice) are caught by TextSight at 71-82%.
For students and academic submitters — Don't rely on Undetectable Maximum to clear institutional detectors. Universities increasingly run multi-detector ensembles, and any single score-reduction AI rewriter's output gets caught by at least one detector in the pool on most passages.
The fundamental asymmetry: We can't run a TPR/FPR table the other direction. Asking "what fraction of TextSight's AI rewriter output does Undetectable detect?" measures Undetectable's validation loop, not detection accuracy. The two products were built for opposite goals.
The detection arms race is real; TextSight + ESL writers writing in authentic voice are still the safest combo. Aggressive score-reduction AI rewriters buy temporary score reduction but compound risk over a portfolio of submissions, because each individual detector is a different probability draw and the institutional norm is moving toward multi-detector ensembles, not single-tool clearance.
The product-shape gap between TextSight and Undetectable shows up everywhere once you see it. Worth understanding before you read the pricing.
The Undetectable product was built around the rewrite engine. The AI rewriter is the primary surface, the aggression slider is the primary control, and the bundled detector exists to confirm the AI rewriter's own output is below the company's internal threshold on a basket of common detectors. Strong on the score-reduction workflow where lower detector scores are the goal. The trade-off is that the detector is not tuned to score arbitrary writing honestly, and the brand framing leans into score-reduction language that creates positioning issues in academic and editorial buying conversations.
TextSight is built the other direction. The detector is the centre of the product with sentence-level highlights, per-line rationale, and a published methodology. The AI rewriter is bundled inside every paid tier on the same monthly word allowance for the calibration workflow: scan, see which rhythms flag, rewrite those specific sentences, recheck, ship. The brand framing is calibration rather than score reduction, which is easier to defend in compliance, classroom, and editorial settings. The trade-off is that the rhythm-preserving AI rewriter pushes scores down meaningfully but not as low as Undetectable Maximum on its most aggressive setting.
Take a paragraph of raw GPT-4 output. Run it through Undetectable Maximum. The score on Undetectable's own detector drops to near zero, and the prose often reads like a different writer rewrote each paragraph from scratch. Run the same paragraph through TextSight rhythm mode. The score drops substantially, the sentence-level highlights show which rhythms still read AI-shaped, and the output preserves more of the original vocabulary and cadence. Different tools for different jobs, not the same tool with different prices.
TextSight Pro is $19.99 monthly or $14.99 monthly on annual billing, unlimited scans plus bundled AI rewriter. Undetectable.ai starts around $9.99 monthly on month-to-month with steep annual discounts on AI rewriter-only allowances. The two prices are not buying the same thing.
Billed $89.88/year, Save $30
Billed $179.88/year, Save $60
Billed $359.88/year, Save $120
Yearly billing saves 25%. Undetectable.ai starts around $9.99/mo on month-to-month for an AI rewriter-only allowance, with steep annual discounts that cut effective monthly rates by roughly half. View full pricing →
Both products are built by serious teams solving different problems. 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, the honest answer is both subscriptions. Undetectable runs the aggressive AI rewriter pass, TextSight runs the independent calibration check and the rhythm-preserving rewrite when voice matters.
Picking between calibration-first detection and score-reduction-first authenticity is workload-specific. Three concrete profiles, three concrete picks.
Delivers AI-assisted drafts to clients who run them through a basket of competing detectors before paying. The only success metric is a score below the client's threshold on every detector they check. Undetectable wins. Maximum mode runs multiple rewrite passes, the annual billing brings per-word cost into a workable range, and the brand recognition shortens the sales conversation. TextSight's rhythm-preserving rewrite trades a few points for voice preservation, which is the wrong trade-off for this workflow.
Half the drafts started as AI-assisted outlines then hand-edited. Needs to ensure each delivery reads honestly under 30 on AI detection without losing the source writer's voice. TextSight wins. Detection on every draft with sentence-level highlights, bundled AI rewriter for the rhythms that still flag, all in one subscription at $14.99 a month on annual Pro. Undetectable's AI rewriter-tuned detector clears content other tools still flag, which means a delivered draft can fail a client's independent detection check, which is the worst possible outcome for a freelancer's reputation.
Mix of original student work, ESL writing, and a handful of suspected AI submissions. TextSight wins, clearly. An honest detector with sentence-level evidence and ESL-aware scoring is the only viable tool for a calibration workflow at an institution. Undetectable's score-reduction-first product is the wrong shape for this job, and the brand framing makes it institutionally awkward to justify to a dean or procurement committee. The .edu Pro price at $13.99 monthly also removes a budget hurdle for individual reviewers.
The full six-tool AI rewriter ranking with output quality, pricing and use-case fit side-by-side.
See the ranking →The journalism-detector head-to-head. OCR, perplexity scoring, 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 commitment. Your first scan in about six seconds.