# Commercial Humanizer Tools — Commercial

_Research angle D — the commercial humanizer products themselves: pricing, API availability, claimed techniques, and detector coverage._
_Research conducted April 2026._

**Research value: high** — the category is crowded (30+ live products), pricing and API details are well-documented, and techniques/positioning reveal clear patterns and gaps.

## Executive Summary

The "AI humanizer" category barely existed before April 2023. By 2026 it has crystallized into a ~$500M+ annual-revenue market (Supwriter estimate, ~20% CAGR to 2032) with three structural segments:

1. **Dedicated detector-bypass humanizers** (Undetectable.ai, StealthGPT, StealthWriter, BypassGPT, Humbot, Phrasly, WriteHuman, HIX Bypass, Humanizer.org, AIHumanizerPro, Conch.ai "Stealth", ZeroGPT Humanizer, Netus AI, GPTinf, Rephrasy, Humanize AI, Humanize AI Pro, Deceptioner, TextToHuman, Rewritely) — dedicated SaaS whose explicit value proposition is evading GPTZero, Turnitin, Originality.ai, Winston AI, Copyleaks, Scribbr, and Content at Scale. Most launched 2023, direct response to first-wave detectors.
2. **General AI writing suites with humanizer sub-features** (Grammarly Humanizer, Jasper Brand Voice, QuillBot, Copy.ai, Writesonic, TextCortex, Smodin, Surfer SEO's in-editor humanizer, Content at Scale's Humanize) — larger platforms that bolted humanization onto existing workflows, usually framed as clarity/voice rather than detection evasion.
3. **Rewriter/spinner legacy tools retrofitted** (Spinbot, Rephrasely, Article Rewriter Tool) — pre-LLM synonym-swap rewriters rebranded as humanizers; consistently the weakest bypass performance.

Undetectable.ai remains the market-reference point: ~11M users (updated; the "15M+" claim from the Feb 2025 Reuters press release is the vendor's figure; Tracxn/G2 profiles show ~11M active as of 2026), ~34 employees (Latka, Sep 2025), $3.7M ARR (Latka, Sep 2025), bootstrapped, no external funding, co-founded by Bars Juhasz — a Loughborough PhD candidate whose prior RAF research on AI-text detection is marketed as the foundation of the humanization model. It is no longer the performance leader: Ryter Pro achieves higher Turnitin and GPTZero bypass rates in 2026 independent testing. Consolidation is emerging (Humanloop → Anthropic, 2025–26) and the API economy is now the real revenue center, with every serious vendor publishing REST endpoints and $100+/month business minimums.

The category is defined by an explicit arms race with detectors and an unresolved ethical cliff: vendors advertise "99.8%" and "100% undetectable" while independent 2026 testing shows wide variance (45% to 94% bypass across the same tool set), the EU AI Act transparency obligations come into force August 2026, and even the best-performing tools degrade meaning in ~10% of samples.

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## Catalog (28 products)

### Dedicated detector-bypass humanizers

#### 1. Undetectable.ai
- **URL**: https://undetectable.ai
- **Vendor**: Undetectable AI (co-founders Christian Perry, Bars Juhasz, Devan Leos). Bootstrapped, no VC, ~34 employees (Sep 2025, Latka data), 11M+ users (down from "15M+" claim in Feb 2025 Reuters release; current G2/Tracxn profiles show ~11M).
- **Launched**: May 1, 2023.
- **Revenue**: $3.7M ARR (September 2025, Latka).
- **Pricing** *(updated April 2026)*: Free (2 humanizations/day, 1K-char cap). Monthly: $14.99/mo (15K words). Annual: from ~$5/mo for 10K words, with a "50% off" yearly deal marketed as 300K words/year. Business "non-expiring credits." API bundled with annual plans; includes unlimited Human Auto Typer and Job Application Bot features added in 2025–2026.
- **API**: Documented REST API. Parameters: `readability`, `purpose` (essay/article/marketing), `strength` (Quality / Balanced / More Human), `model` (v2 / v11 / v11sr). Additional bundled tools: AI Essay Writer, AI SEO Writer, Human Typer, Word Counter.
- **Claimed techniques**: Multi-model routing ("trained to recognize and rewrite detector-sensitive patterns"). 99.8% success rate marketing claim.
- **Detector coverage**: Markets against GPTZero, Turnitin, Originality.ai, Copyleaks, Winston AI, ZeroGPT. Independent 2026 testing: 73–88% bypass. Consumer-grade detectors (GPTZero, ZeroGPT) see 96–97% bypass; Turnitin holds at ~89%; Originality.ai drops performance to ~68%. No longer the clear performance leader — Ryter Pro and Walter Writes AI now benchmark ahead of it in several independent 2026 tests.

#### 2. StealthGPT
- **URL**: https://stealthgpt.ai
- **Pricing** *(updated April 2026)*: Base plan $32/mo (billed weekly) or $40/mo (higher tier, billed weekly) — a significant restructuring from the previous Essential $14.99 / Pro $19.99 / Exclusive $29.99 tiering. Optional "Samurai" engine add-on remains at $4.99/mo. A 7-day free trial is now offered (no free permanent tier). Token-based API. Note: XYZ AI Inc (StealthGPT parent) announced a new funding raise at higher valuation in late 2025.
- **API**: Yes, token-metered. Browser extensions and Google Docs / Gmail integrations added on higher tiers.
- **Claimed techniques**: Proprietary "Ghost" (standard) and "Samurai" (premium) engines. Bundled essay generator with real-citation insertion and auto-bibliography — heaviest academic positioning in the category.
- **Detector coverage**: Markets universal bypass. 2026 independent testing: 60–82% bypass depending on test and content length. Consistently fails against Originality.ai and Turnitin in rigorous tests. One AIXRadar test showed 100% AI on GPTZero. Phrasly's 2026 review put it at the bottom third of dedicated humanizers for Turnitin performance.

#### 3. StealthWriter.ai
- **URL**: https://stealthwriter.ai
- **Vendor**: AiVantage LLC (founder Maher Mansour, Dubai). Bootstrapped.
- **Launched**: 2023.
- **Pricing**: Free tier; Basic $20/mo (2K words/input); Premium $50/mo (5K words/input). Largely no-refunds.
- **API**: **No** — web-only, English-only, explicit.
- **Claimed techniques**: Light / Medium / Aggressive rewrite levels; per-sentence alternative rewrites with per-sentence detection scores; built-in detector for before/after comparison.
- **Detector coverage**: Internal multi-detector scan. Independent 2026 testing: 53–60% average bypass — middle-tier. Trustpilot 2.1/5 with "scam" complaints (UndetectedGPT review).
- **Notable**: Strongest published privacy posture — FAQ states text "not stored after processing" and "not used for training"; ToS explicitly prohibits academic misconduct.

#### 4. BypassGPT
- **URL**: https://bypassgpt.ai
- **Pricing**: Free 150 words/month (80 words/input); Basic $8/mo (5K words); Pro $12/mo (30K words); Unlimited $30/mo. Flash-sale volatility is notable. 3-day money-back under 1,000 words used.
- **API**: Yes, 250-word free test allowance, sliding-scale pricing.
- **Claimed techniques**: "Advanced humanization model trained on 200M+ AI and human texts." Fast / Creative / Enhanced modes. Multilingual UI.
- **Detector coverage**: "100% undetectable" marketing against all major detectors. No published methodology. ToS disclaims HIPAA.

#### 5. Phrasly
- **URL**: https://phrasly.ai
- **Vendor**: Phrasly.AI (California HQ, distributed team). Reports 2M+ users, 50M+ documents processed.
- **Pricing**: Free tier; Unlimited ~$10.99/mo billed annually (~$19.99/mo monthly). **Business API: $100/month minimum** at $0.14/1K words (humanize) + $0.02/1K words (detect).
- **API**: Yes, business tier. Early docs show AI Detector + Balance endpoints (phrasly-api.readme.io), humanizer endpoint in progress per 2026 docs.
- **Claimed techniques**: "100% proprietary AI model trained on over 1 million pages of human-written content" — explicitly positions against synonym-swap paraphrasers ("restores cadence and voice, not synonym swapping"). Modes: Easy / Medium / Aggressive. Per-process 5K-word cap.
- **Detector coverage**: Markets all major detectors. 2026 independent testing: 45% average — bottom of list in one Humanizer AI benchmark (ranked 7th of 10).

#### 6. HIX Bypass (HIX.AI)
- **URL**: https://bypass.hix.ai
- **Vendor**: HIX.AI (broader multi-tool writing suite). **Trustpilot: 2.6/5** across ~169 reviews (April 2026); common complaints include unauthorized charges after cancellation and random gibberish in humanized output.
- **Pricing** *(updated April 2026)*: Pro $29.99/mo (billed monthly) or $14.99/mo (billed yearly, 50K words/mo). Unlimited $59.99/mo (billed monthly) or $39.99/mo (billed yearly). 300-word free trial for API.
- **API**: Yes, gated via `support@hix.ai`. Endpoint `bypass.hix.ai/api/hixbypass/v1/`. 2,000-word/request cap.
- **Claimed techniques**: 50+ language support, "Aggressive" and "Latest" modes. "Comprehensive privacy safeguards" (marketing).
- **Detector coverage**: 2026 independent testing places overall bypass at ~75%, meaning one in four detectors still catches the output. Turnitin bypass is inconsistent (20–76% AI flagged across runs). Cannot reliably bypass Turnitin in current testing. Value proposition is best for users already inside the HIX.AI ecosystem.

#### 7. WriteHuman
- **URL**: https://writehuman.ai
- **Pricing** *(updated April 2026, major revision)*: Web platform restructured — Basic $9/mo, Pro $12/mo, Ultra $36/mo. API: Standard $29/mo (125K words/mo, 10 req/min, 2K words/request, 2 concurrent) or Premium $69/mo (400K words/mo, 60 req/min). Word packs $25/125K. Effective rate ~$0.17–0.23/1K words (unchanged). March 2026 update: full website redesign and significant humanizer model upgrade with improved scores across major detectors.
- **API**: `POST https://api.writehuman.ai/v1/humanize`, Bearer token, 40+ languages, <2s response. API formally launched and documented in 2025.
- **Claimed techniques**: Three intensity modes, built-in "naturalness scanner," Google Docs history-replay Chrome extension.
- **Detector coverage**: Markets all detectors. 2026 independent reviews rate WriteHuman lower than BypassGPT on raw bypass but note stronger output quality for human readers. The canonical internal-vs-external scorecard gap (internal "100% human" vs GPTZero "100% AI" on the same text) remains the most-cited example of vendor-scorecard illusion. AIXRadar: weaker bypass than BypassGPT but cleaner ethics framing.

#### 8. Humbot
- **URL**: https://humbot.ai
- **Pricing**: Free ($0, 200 basic words/mo, 100-word input cap); Basic $7.99/mo (3K words); Unlimited $9.99/mo; Pro $9.99/mo (30K words). 7-day refund under 1,000 words used.
- **API**: Yes (advertised), docs partially gated/JS-rendered.
- **Claimed techniques**: Quick / Enhanced / Advanced modes. "Gemini 3-powered article rewriter" (vendor claim). Bundled multi-detector AI checker, plagiarism, grammar, translator, citation generator, ChatPDF reading. "Basic words vs advanced words" split credit model.
- **Detector coverage**: 2026 testing: 60% average bypass (Humanizer AI benchmark, rank 4); 45.5% against Originality.ai specifically (weakest Originality.ai performance of major vendors).

#### 9. GPTinf
- **URL**: https://gptinf.com
- **Pricing**: Lite $4.99/mo (5K words); Pro $12.49/mo (25K words); Unlimited $29.99/mo. Cheapest entry tier in the category. ~240-word free across guest + account.
- **API**: Not emphasized.
- **Claimed techniques**: "Ultra Humanizer." Encrypted per-user history dashboard. Unusual claim that it "doesn't even use AI" to humanize (vendor claim, unverified) and doesn't train on user text.
- **Detector coverage**: Markets universal bypass.

#### 10. Netus AI
- **URL**: https://netus.ai
- **Pricing**: Free 50 credits/mo (≈500 words for bypasser); Basic $14/mo; Standard $30/mo. **1 credit = 10 words** for bypasser; unlimited AI detector on paid tiers.
- **API**: Not primary focus.
- **Claimed techniques**: "Algorithm modifies AI content to mimic human writing style." Credit-based rather than subscription word-pool.
- **Detector coverage**: Generic "all detectors" marketing.

#### 11. Deceptioner
- **URL**: https://deceptioner.com
- **Pricing**: Standard and Premium tiers (~$10/mo entry) + separate rewriter/generator word pools + top-up packs.
- **API**: **v2, task-based (create → poll), 10,000-char per-task cap.** Most transparent API in the category.
- **Claimed techniques**: **Detector-profile selector** (Turnitin, GPTZero, Winston AI, Originality.ai) + **stealth slider 0–1** that explicitly trades readability for evasion. "Optimization rather than generic paraphrasing."
- **Detector coverage**: Explicit per-detector targeting. Marketing does not overclaim.
- **Privacy**: History stored **locally in browser for 30 days**, not server-side — most privacy-forward server architecture.

#### 12. Humanize AI (humanizeai.com / humanizeai.io)
- **URL**: https://humanizeai.com, https://humanizeai.io
- **Note**: Two separate products with similar names. `.com` pricing: Essential $7/mo (30K words), Standard $12/mo (75K), Pro $29/mo (225K). `.io` pricing: Standard $4/mo billed annually, Premium $6/mo, Elite $7/mo (up to unlimited words).
- **API**: Varies by product.
- **Claimed techniques**: Keyword/phrase freezing (3–12 slots by tier); Standard / Shorten / Expand / Simplify transforms; "4x ultra-fast" processing on Elite.
- **Detector coverage**: 2026 independent testing (TwainGPT): Against major detectors on raw GPT output — GPTZero 100% AI, Turnitin 100%, ZeroGPT 88%, QuillBot 100%. Only partial reduction on ZeroGPT; failed the others. Illustrates the gap between marketing and reality in the budget tier.

#### 13. Humanize AI Pro (AIHumanizerPro / thehumanizeai.pro)
- **URL**: https://www.aihumanizerpro.ai
- **Pricing**: Free (9K words/mo, 300 words/request); Essential $4.16/mo annual (300K words/mo); Premium $8.33/mo annual (600K words/mo, 2K words/request).
- **API**: Not prominent; positioned as consumer.
- **Claimed techniques**: "Zero AI Mode," customizable tonality, DOCX/PDF/TXT input, real-time AI detection scoring. Testimonials cite 96% → 2% detection drops.
- **Detector coverage**: Marketed against Turnitin, GPTZero, Originality.ai. Separately, `thehumanizeai.pro` markets itself as free/unlimited with a 99.8% bypass claim.

#### 14. AIHumanizer.com / HumanizerAI.com
- **URL**: https://humanizerai.com
- **Pricing**: Starter $10/mo (10K words/mo); Pro $21/mo (50K); Business $35/mo (200K). Annual billing discounted.
- **API**: Yes, included with paid tiers.
- **Claimed techniques**: Light / Medium / Bypass modes. Document storage, in-platform detector.
- **Detector coverage**: Claims 80% average bypass in own benchmark; positions as budget API alternative.

#### 15. Humanizer.org
- **URL**: https://humanizer.org
- **Pricing**: Standard $19.99/mo (8K words/mo); Premium $29.99/mo (80K); Unlimited $49.99/mo (unlimited). Annual plans heavily discounted (as low as $9.99 Standard annual).
- **API**: Not primary.
- **Claimed techniques**: 50+ languages, "preserves original meaning," plagiarism prevention. Per-tier input limits (500 words → unlimited).
- **Detector coverage**: Markets Turnitin, GPTZero, Originality.ai.

#### 16. Conch.ai (Conch AI / Stealth Writer)
- **URL**: https://www.getconch.ai
- **Pricing**: Monthly $9.99, Quarterly $7.99/mo, Yearly $3.99/mo (billed $47.88). `.edu` 10% discount. 7-day money-back.
- **API**: Not prominent.
- **Claimed techniques**: "Stealth" humanizer + "Enhance" mode for detection bypass. **Personalized-style cloning** — upload a PDF of your writing to mimic voice. Bundled study suite: flashcards, mindmaps, citations.
- **Detector coverage**: Generic. Positioning: student-first writing assistant, not a dedicated bypass tool.

#### 17. ZeroGPT Humanizer
- **URL**: https://zerogpt.com/ai-humanizer (built into the detector product)
- **Pricing**: Free tier (basic); PRO $7.99/mo; PLUS $14.99/mo; MAX $18.99/mo. All paid tiers include humanization.
- **API**: Not primary for the humanizer mode.
- **Claimed techniques**: Fast / Creative / Enhanced modes, real-time side-by-side comparison with ZeroGPT's own detector. Unusual **self-detector + humanizer vertical integration**.
- **Detector coverage**: Optimized primarily against ZeroGPT's own detector (obvious conflict of interest); third-party detectors frequently still flag the output.

#### 18. Rephrasy
- **URL**: https://www.rephrasy.ai
- **Pricing**: From $13/mo. Sister site Rephraser.co: $4.95/week, $9.95/mo, $49.95/yr. Bulk API credit packs.
- **API**: **Multi-model API**: `v3` (recommended), `Undetectable Model v2`, `Undetectable Model`, `SEO Model`. Flat 0.1 credits + 0.1 credits per 100 words. Language auto-detection. Response includes Flesch Score. Companion Detector API.
- **Claimed techniques**: **Writing-style cloning** (upload sample), creative/journalistic/professional voices on v3. Bypass GPTZero, Turnitin, Copyleaks claimed. 50+ languages.
- **Detector coverage**: Markets comprehensive coverage; no independent reproducible benchmarks published.

#### 19. TextToHuman
- **URL**: http://texttohuman.com
- **Pricing**: **Free, unlimited, no signup.** 25+ languages.
- **API**: No public API.
- **Claimed techniques**: **"Autopilot Mode"** — auto-iterates 2–3 passes until detection drops below ~15%. **Smart Alternatives** — clickable sentence-level rewrites with per-sentence detection scores. Two engines: Stealth Model (bypass) vs Premium Model (readability). SEO keyword preservation.
- **Detector coverage**: Ranked #1 in multiple 2026 review roundups; privacy-first, no storage.

#### 20. Rewritely
- **URL**: https://rewritelyapp.com
- **Pricing**: Free plan (5,000 words/mo) + paid tiers.
- **API**: Not prominent.
- **Claimed techniques**: **33-signal transparency report** — uniquely shows *what* was changed and *why*, by signal. <5s processing. Targets specific weak signals rather than aggressive vocabulary substitution.
- **Detector coverage**: 2026 independent tests cited Rewritely as top performer in naturalness and voice preservation.

#### 32. Walter Writes AI *(added April 2026)*
- **URL**: https://walterwrites.ai
- **Launched**: ~2024–2025; emerged in Reddit threads as a consistent top performer by early 2026.
- **Pricing**: Plans from ~$8/mo (30K words) or $10/mo (10K words, Starter) → $19/mo (55K words, Pro). Free trial: 300 words, no credit card or login required.
- **Claimed techniques**: Structural rewrite rather than synonym swap; positions around output quality as much as bypass rate. Suits writers who prioritize finished quality over raw evasion.
- **Detector coverage**: 79.7% Turnitin bypass in pre-Aug-2025 testing. Post Turnitin's August 2025 "AI bypasser" detection update, ~38% of content is now flagged as AI on Turnitin; Originality.ai catches ~45% of output. Strong on consumer-grade detectors (GPTZero, ZeroGPT). Featured heavily in r/BypassAiDetect threads and r/ChatGPTPro in 2025–2026 as a top community recommendation.
- **Notable**: Turnitin's August 2025 model update hit Walter Writes harder than most dedicated humanizers. TikTok paid-promotion wave (Oct 2025–Feb 2026, 12+ creators with 100K+ followers) inflated community hype.

#### 33. Ryter Pro *(added April 2026)*
- **URL**: https://www.ryter.pro
- **Launched**: 2025.
- **Pricing**: Free limited tier. Basic $6/mo billed annually (100 credits/mo, 5K chars/session). Professional $12/mo billed annually (500 credits/mo, 10K chars/session, full API access, priority support, faster response, Pro Algorithm and New Model).
- **API**: Full API access on Professional plan.
- **Claimed techniques**: "Pro Algorithm" and "New Model" — specific implementations not publicly documented. Fastest processing speed in 2026 independent tests: >5,000 words/minute.
- **Detector coverage**: Leading independent bypass rates in April 2026 roundups — 97% on GPTZero, 94% on Turnitin; no other tool tested within five percentage points of its Turnitin score in AI Natural Write's 2026 evaluation. Multilingual capability rated genuine (unlike many competitors who support 50+ languages with uneven quality). Least manual cleanup required of any platform in the same evaluation set.

#### 34. GPTHuman.ai *(added April 2026)*
- **URL**: https://gpthuman.ai
- **Launched**: ~2024–2025.
- **Pricing**: Free tier (300 words/output). Paid: $9.99/mo unlimited (2K words/output cap). Steep word-limit ceiling on paid plan is the primary complaint.
- **API**: Not prominent.
- **Claimed techniques**: Tone selector (Standard / High School / College / PhD); mode selector (Professional / Balanced / Enhanced). Bundled humanizer + detector + paraphraser in single interface. Supports PDF and Word file import. Reports a "Stealth Score" on output.
- **Detector coverage**: 2026 independent testing (Leap AI): 37.4% average bypass — well below marketing claims and below free competitors. Consistently passes Winston AI in some tests. Per Substack reviewer (Apr 2026): top-4 pick in a 30-tool test based on output quality more than raw bypass numbers.

### General writing suites with humanizer features

#### 21. QuillBot (with Humanizer)
- **URL**: https://quillbot.com
- **Pricing**: ~$8.33/mo Premium (annual).
- **API**: Commercial API for paraphrasing exists; humanizer mode separately gated.
- **Claimed techniques**: Six paraphrase modes (Standard / Fluency / Formal / Simple / Expand / Shorten) **plus a dedicated humanizer mode** added to compete with 2023-era bypass entrants. Grammar, plagiarism bundled.
- **Detector coverage**: Positioned for clarity; detector-bypass framing is secondary.

#### 22. Copy.ai (AI Humanizer tool)
- **URL**: https://www.copy.ai/tools/free-ai-humanizer
- **Pricing**: Free tool; Copy.ai workflow platform paid tiers ($49/mo+).
- **API**: Copy.ai workflows API, not humanizer-specific.
- **Claimed techniques**: NLP pattern/tone/style adjustment. Positioned as "makes AI content conversational, relatable, authentic" — deliberately avoids detector-bypass framing. Brand voice controls at the workflow layer.
- **Detector coverage**: Not marketed for bypass.

#### 23. Writesonic AI Text Humanizer
- **URL**: https://docs.writesonic.com/docs/ai-text-humanizer
- **Pricing**: Part of Writesonic ($16/mo+).
- **API**: Bundled.
- **Claimed techniques**: In-editor "Humanize" icon. **"Enhanced Readability" toggle explicitly warns it may increase AI detection risk** — rare vendor honesty about the readability/stealth tradeoff.
- **Detector coverage**: Marketed against major detectors but disclaims guarantees.

#### 24. Grammarly Humanizer Agent
- **URL**: https://www.grammarly.com/ai-humanizer
- **Pricing**: Grammarly Premium $12/mo+.
- **API**: Grammarly Enterprise API covers tone; humanizer agent consumer-only.
- **Claimed techniques**: Dedicated Humanizer agent for ChatGPT/Claude/Gemini output. Four preset voice styles + **custom voice profile trained on user writing sample**. Six languages (EN/ES/FR/DE/PT/IT). Paired with tone-rewrite suggestions for framing/confidence/friendliness.
- **Detector coverage**: **Explicitly framed as clarity/voice, not detection evasion** — legitimacy play from a mainstream vendor.

#### 25. Jasper Brand Voice (+Brand IQ)
- **URL**: https://www.jasper.ai/brand-voice
- **Pricing**: Pro $59–69/mo; Business custom.
- **API**: Yes.
- **Claimed techniques**: Per-org Brand Voice profiles, Visual Guidelines, Style Guides, Jasper IQ for brand-logic governance. Paraphrasing tool with tone modes.
- **Detector coverage**: Not a bypass product; brand-voice humanization for enterprise marketing.

#### 26. TextCortex
- **URL**: https://textcortex.com
- **Pricing**: Free (20 daily creations); Premium 150/500/1000 at $23.99/mo+; Unlimited $119.99/mo ($83.99 annual). 20% annual discount.
- **API**: Yes — included in Unlimited plan; requestable on others.
- **Claimed techniques**: Model-agnostic access to all major LLMs; 30K+ app integrations; 25+ languages; rewriting and translation tools; GDPR-compliant EU servers with no-data-collection enterprise policy.
- **Detector coverage**: Positions as writing-productivity platform; rewriting is a generic feature, not a bypass product. **Note**: TextCortex itself markets a paraphraser/rewriter, not a dedicated "humanizer" — the "humanizer" comparisons in review sites refer to a separate tool (AI Humanizer) rather than a TextCortex feature.

#### 27. Smodin (Rewrite & Recreate API)
- **URL**: https://smodin.io
- **Pricing**: Free ($0, 1,000 words/day, 3 rewrites/day); Essentials $10/mo (6K words/day); Productive $29/mo (25K words/day, unlimited rewrites).
- **API**: Yes — **Rewrite and Recreate API** with explicit "AI detection removal," uniqueness, and **"AI watermark removal"** options. Plagiarism Checker API and AI Content Remover API as separate products. 50+ languages.
- **Claimed techniques**: Rewriter + translator + plagiarism + citation generator + content detector bundle. "Fast real-time responses."
- **Detector coverage**: 2026 testing: 81% average bypass across Turnitin, GPTZero, Copyleaks, Originality.ai — but meaning-preservation issues in 10% of samples.

#### 28. Surfer SEO Humanizer
- **URL**: https://surferseo.com (inside Surfer AI editor)
- **Pricing**: Surfer Discovery $49/mo (humanizer included); Standard $99/mo; Pro $182/mo; Peace of Mind $299/mo; Enterprise $999/mo.
- **API**: No standalone humanizer API.
- **Claimed techniques**: **Credit-based**; humanization consumes article credits (10–30 articles/mo depending on tier). English only. Integrated only within Surfer AI editor.
- **Detector coverage**: 2026 testing: 76% average bypass — materially weaker than dedicated humanizers (99.2% cited in same test). Adequate only for users already subscribed for SEO.

#### 29. Content at Scale — Humanize
- **URL**: https://contentatscale.ai
- **Pricing**: Paid subscription; humanizer bundled with AI detector and SEO content writer. Detector standalone has free tier + paid API.
- **API**: AI detector API; content-writer API.
- **Claimed techniques**: Multi-model ensemble detector (neural classifiers + perplexity + burstiness) with three-dimensional scoring (predictability, probability, pattern). Humanizer co-developed to beat the vendor's own detector.
- **Detector coverage**: Vertical integration (detector + humanizer from same vendor). One 2026 test: after processing through a third-party humanizer (Humanizer PRO), Content at Scale's detector dropped from 67% AI to 6% AI across 50 samples (94% bypass).

#### 30. Spinbot
- **URL**: https://spinbot.com
- **Pricing**: Free plan (135 words/mo, ads); Premium $9.95/mo; from $4.17/mo.
- **API**: No public API.
- **Claimed techniques**: Basic synonym-swap paraphrasing; no tone or AI controls. English-mostly.
- **Detector coverage**: 2026 head-to-head benchmarks: ~81% bypass vs competitors at 82–99.6%. 9–15s processing (vs 2–3s modern tools). Reviewers consistently describe Spinbot as "no-frills free spinner" that predates the humanizer category and has not adapted to perplexity/burstiness-based detectors.

#### 31. Scribbr Humanizer
- **URL**: https://www.scribbr.com/ai-humanizer/
- **Vendor**: Scribbr (academic proofreading brand owned by QuillBot / Learneo parent group).
- **Pricing**: Free limited humanization checks; Scribbr's paid plagiarism+AI checker bundles include access. Per Scribbr positioning: humanizer is a supporting utility to their detector, not a primary product.
- **API**: No public humanizer API.
- **Claimed techniques**: Framed as "improving flow and clarity" rather than bypass — mirrors Grammarly's posture. Academic-integrity warning surfaced prominently.
- **Detector coverage**: Scribbr's own detector claims 85–92% accuracy on unedited AI, 60–75% on edited; 8–14% false positive rate. Humanizer positioned as ethical editing aid within that context.

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## Pricing Patterns

| Segment | Entry price | Typical mid-tier | API minimum |
|---|---|---|---|
| Budget consumer | $4.17–7.99/mo (Spinbot, GPTinf Lite, Humbot Basic) | $9.99–12.99/mo | N/A |
| Mainstream humanizer | $6–9.99/mo (Ryter Pro Basic, Undetectable annual, Conch, ZeroGPT PRO) | $12–19/mo | $29/mo (WriteHuman) |
| Premium humanizer | $9–12/mo (WriteHuman Basic/Pro, Ryter Pro Professional) | $19–36/mo | $69–100/mo (WriteHuman Premium, Phrasly API) |
| Suite-bundled | $49/mo+ (Surfer), $59/mo (Jasper), $119/mo (TextCortex Unlimited) | $99–199/mo | enterprise custom |

*Note: Undetectable.ai's pricing restructured in 2025–2026. Monthly plan now $14.99/mo (was $9.99). Annual "50% off" deal markets at ~$5/mo for 10K words. WriteHuman restructured web pricing to $9/$12/$36 (was $18/$27/$48). StealthGPT moved to weekly billing at $32–40/mo, departing from the monthly $14.99–29.99 tiering.*

**Per-1K-words API economics** where disclosed: WriteHuman $0.17–0.23; AIHumanizerAPI ~$0.20; Phrasly $0.14 humanize + $0.02 detect; Rephrasy ~0.1 credit/100 words. Business API minimums cluster at $99–100/month — a de facto threshold for "serious" humanizer API usage.

## Detector Coverage (vendor-reported vs independent)

*Updated April 2026. Turnitin's August 2025 "AI bypasser" detection model and February 2026 recall update mean pre-Aug-2025 Turnitin numbers are now stale for all tools.*

| Humanizer | Vendor claim | Independent 2026 testing |
|---|---|---|
| Ryter Pro | n/a | 97% GPTZero, 94% Turnitin — highest in category (AI Natural Write Apr 2026) |
| Undetectable.ai | 99.8% | 73–88% avg; 96–97% on GPTZero/ZeroGPT, 89% Turnitin, 68% Originality.ai |
| Phrasly | "most advanced" | ~80% avg in Apr 2026 tests (up from 45% in earlier benchmark — model updated) |
| HIX Bypass | 99%+ | ~75% avg; inconsistent Turnitin (20–76% flagged) |
| Walter Writes AI | n/a | Pre-Aug 2025: 79.7% Turnitin; post-Aug 2025 update: ~62% Turnitin, 55% Originality.ai |
| Humaniser | n/a | 93% (own benchmark); 96% AI on GPTZero in AIXRadar test |
| Humanizer PRO | 94% vs Content at Scale | 94% (own test) |
| StealthGPT | universal | 60–82% range; fails Originality.ai/Turnitin in rigorous tests |
| Smodin | n/a | 81% avg (4 detectors) |
| HumanizerAI.com | n/a | 80% avg |
| Humbot | universal | 60% avg, 45.5% on Originality.ai (weakest) |
| StealthWriter | universal | 53–60% avg |
| GPTHuman.ai | n/a | 37.4% avg (Leap AI); strong on output quality vs raw bypass |
| Humanize AI (.com) | all detectors | 0% bypass on GPTZero/Turnitin/QuillBot (TwainGPT) |
| Surfer Humanizer | n/a | 76% avg |
| Spinbot | n/a | ~81% (mechanical) |

The pattern is unambiguous: **no vendor's marketing claim survives independent testing**, and the gap between internal scorecards and third-party detectors is so wide (WriteHuman's internal scanner disagreed with GPTZero by 100 points on the same text) that vendor scores are functionally meaningless.

## Claimed Techniques (what vendors actually do)

Consolidating across the catalog:

1. **Stealth ↔ readability slider.** Deceptioner (`stealth` 0–1), Undetectable.ai (`strength`: Quality/Balanced/More Human), Phrasly / StealthWriter / BypassGPT (Easy/Medium/Aggressive, Fast/Creative/Enhanced). Writesonic alone explicitly warns "readability increases detection risk."
2. **Detector-target profiles.** Deceptioner, Undetectable.ai, Humaniser let users pick Turnitin / GPTZero / Originality.ai / Winston / Copyleaks. Implies per-detector adversarial tuning or heuristic routing.
3. **Multi-model routing / portfolios.** Undetectable.ai ships v2/v11/v11sr; Rephrasy ships v3 + Undetectable v2 + SEO Model; Humbot claims Gemini 3; TextToHuman splits "Stealth Model" from "Premium Model." Internal A/B across multiple engines rather than one tuned model.
4. **Sentence-level alternatives / diffs.** StealthWriter, TextToHuman, and Rewritely surface per-sentence alternatives with individual detection scores. Reframes humanization as curated choice rather than opaque black box.
5. **Iterative auto-pass ("autopilot").** TextToHuman explicitly iterates 2–3 passes until detection drops below ~15%. Reflects the independent research finding that three passes through a quality humanizer reliably defeats GPTZero.
6. **Citation / keyword freezing.** Humbot, StealthGPT, Phrasly, Humanize AI — "freeze references and keywords" to prevent rewrites from corrupting academic citations or SEO targets. A workflow concession to academic use cases the same vendors disclaim in their ToS.
7. **Transparency reports.** Rewritely (33 signals, "what changed and why"), Deceptioner's explicit stealth/readability curve. Counter-trend in a black-box category.
8. **Training-data provenance as a marketing wedge.** Phrasly ("1M+ real human articles, not synthetic"), BypassGPT ("200M+ AI and human texts"), Undetectable.ai (Juhasz's RAF detection research). Dataset sourcing as differentiator.
9. **Writing-style cloning.** Grammarly (user writing sample), Jasper (per-org Brand Voice), Conch.ai (PDF upload), Rephrasy (style sample + creative/journalistic/professional presets). Shift from generic "sound human" to "sound like *me/us*."
10. **AI watermark removal as an explicit API parameter.** Smodin's Rewrite API exposes this as a flag — the most direct acknowledgement of Google/OpenAI's SynthID-style provenance systems as adversarial targets.
11. **Self-detector + humanizer vertical integration.** ZeroGPT, Content at Scale, and Undetectable.ai all ship both sides. Conflict of interest is obvious — internal detectors are tuned against the same model that the humanizer optimizes past.

## Marketing / Technique Quotes

- **Undetectable.ai homepage**: "Best AI Detector & Humanizer Tool" with a claimed **"99.8% Success Rate"**.
- **Humanize AI Pro**: **"99.8% bypass rate"**, "free, no signup required," "unlimited usage."
- **HumanifyLab**: **"Neutralize Every Detector in Seconds"**, **"99.9% bypass rate"**, "#1 Rated Humanizer 2026."
- **Phrasly**: "100% proprietary AI model trained on **over 1 million pages of human-written content**" — framing humanization as "cadence and voice restoration rather than synonym swapping."
- **Deceptioner docs**: a `stealth` parameter (0–1) that **"controls the readability vs. evasion balance"** and an explicit **target-detector selector** — "an explicit optimization approach rather than generic paraphrasing" (Nerdbot 2026 summary).
- **StealthWriter FAQ**: Submitted text is **"not stored after processing"** and **"not used for training"**. ToS: "not a cheating tool."
- **Smodin API**: Rewrite and Recreate endpoints ship with explicit **"AI detection removal," "uniqueness," and "AI watermark removal"** options (smodin.io API docs).
- **Writesonic docs (rare honest tradeoff)**: The humanizer's Enhanced Readability toggle "may **increase AI detection risk**."
- **BypassGPT**: "Advanced humanization model trained on **200M+ AI and human texts**"; service "**not tailored for HIPAA**."
- **Grammarly AI Humanizer**: Positions as **clarity and voice, not bypass** — "four preset voice styles or a custom voice profile trained on a user writing sample."
- **Surfer SEO Humanizer review (Humanize AI Pro 2026)**: "76% bypass rate… compared to 99.2% for dedicated humanizers." **"Adequate if you already subscribe to Surfer for SEO."**
- **Nerdbot 2026 synthesis**: The category is **"an arms race between detector heuristics and paraphrasing/rewriting strategies"** — "if your goal is 'guaranteed bypass,' treat that as inherently unstable and ethically risky."
- **Hayim Salomon, Medium (April 2026)**: The detector/humanizer arms race is **"structurally unwinnable"**; after "three passes through a quality humanizer, no tested detector consistently identified content as AI-generated," with GPTZero's detection rate dropping to 18%.
- **TwainGPT review of Humanize AI**: "Only partially reduced detection on ZeroGPT but failed to bypass other major detectors… marketing claims about bypassing 'ALL detectors' **not substantiated by testing**."

## Trends

1. **API-first is now the real revenue center.** Every serious vendor (Undetectable, WriteHuman, Phrasly, HIX, BypassGPT, Rephrasy, Smodin, AIHumanizerAPI, Humbot, Ryter Pro) publishes REST endpoints. $99–100/mo business minimums have become the de facto entry. Consumer subscriptions funnel into higher-margin B2B integration.
2. **Writing-style cloning displaces generic "sound human."** Grammarly (user sample), Jasper (org voice), Conch (PDF upload), Rephrasy (style preset). The 2026 product narrative is shifting from "evade detectors" to "sound like you."
3. **Vertical integration of detector + humanizer.** ZeroGPT, Content at Scale, Undetectable.ai, and GPTHuman.ai all sell both sides. The conflict of interest is unresolved and increasingly disclosed in independent reviews.
4. **Multi-pass / autopilot is table stakes.** TextToHuman's auto-iteration pattern is being adopted by competitors. Reflects the independent research finding that 3 passes reliably defeats GPTZero.
5. **Transparency as differentiation.** Rewritely (33-signal report), Deceptioner (explicit stealth curve + detector target), StealthWriter (no-storage FAQ). In a black-box category, explaining the diff is a feature.
6. **AI watermark removal as an exposed flag.** Smodin's API explicitly offers `watermark_removal` as a parameter — the clearest acknowledgement yet that SynthID-style provenance is the next adversarial target.
7. **Legitimacy positioning by mainstream vendors.** Grammarly (September 2025 dedicated humanizer launch), Jasper, Copy.ai, Writesonic, Scribbr, Surfer all frame humanization as clarity/voice — deliberately distancing from detector-bypass framing. QuillBot added a dedicated humanizer mode in late 2025, though it achieves only ~47% average bypass, making it effectively a coin flip.
8. **Free-unlimited budget tier is a real product.** TextToHuman, Humanize AI Pro, Humaniser, and Ryter Pro's limited free tier offer free humanization with no signup — a direct commoditization threat to the $10–20/mo paid tier.
9. **Consolidation into LLM vendors.** Humanloop → Anthropic (2025–26) signals that prompt-management infrastructure is being absorbed; expect Anthropic/OpenAI-native humanization tooling within 12–18 months.
10. **Regulatory hedge in ToS.** Vendors who once marketed "100% undetectable" now insert academic-integrity disclaimers (StealthWriter, Humbot, Phrasly, Deceptioner). Marketing headers haven't caught up with legal footers.
11. **Turnitin's counter-move is operational and improving.** Turnitin shipped AI bypasser detection in August 2025, updated the model again in February 2026 to improve recall while keeping false positives below 1%. The August 2025 update measurably degraded several top humanizers' Turnitin bypass rates (Walter Writes: from 79.7% to ~62%). English-only for now. Vendors that previously marketed Turnitin bypass now caveat or omit that claim.
12. **New entrants competing on speed and Turnitin performance.** Ryter Pro (2025 launch) achieved the strongest independent Turnitin bypass numbers in 2026 testing while being the fastest processor (>5K words/minute). Walter Writes AI built a quality-first positioning that attracted organic community growth before a paid influencer wave in 2025–2026. These tools are displacing StealthGPT and HIX Bypass in recommendation threads.

## Gaps / Open Questions

- **No reproducible benchmarks.** Every vendor cites internal success rates; none publishes methodology or test corpora. Independent tests on the same tools vary by 20–40 percentage points. "99.8%" claims cannot be independently verified.
- **Detector-scorecard illusion.** A humanizer's built-in "100% human" scanner is routinely 100 percentage points off from external detectors on the same text. Vendor-internal scoring is not a credible product feature.
- **False positives on non-native English.** Stanford research: detectors flag 61% of non-native human essays as AI. This creates real demand for humanizers as a **defensive tool for actual humans** — but **no vendor has built a product narrative around this legitimate case.**
- **Pricing volatility.** BypassGPT in particular uses flash-sale pricing. Any price in this catalog may drift within weeks.
- **No dominant enterprise brand-voice humanizer.** Jasper owns marketing brand voice; Grammarly owns knowledge-worker tone. **Enterprise agent-output humanization** (support agents, internal docs, customer-facing AI agents) is an open commercial space — no clear winner.
- **No provenance-preserving humanizer.** Academic work (Naunyn-Schmiedeberg 2026) suggests retrieval- or provenance-based defenses; no commercial product currently markets "humanize while preserving verifiable authorship signal." Potentially the most defensible positioning once EU AI Act transparency obligations bite.
- **No open-source reference humanizer** analogous to jailbreak prompts like "DAN." The commercial category has no OSS anchor; prompt-marketplace listings ($2.99–$6.99 on PromptBase) are the closest thing, and they converge on the same rules (vary sentence length, use contractions, ban "delve" / "tapestry" / "furthermore" / "in conclusion").
- **Legal exposure unquantified.** Vendors simultaneously market detector-bypass and disclaim academic misconduct in ToS. No public enforcement action yet, but **EU AI Act transparency obligations (August 2026) and FTC's "AI to trick, mislead, or defraud is illegal" framing are the next inflection point.**
- **Meaning preservation is unmeasured.** Smodin's 10% meaning-drift rate is one of the only published numbers. Most vendors don't measure semantic fidelity at all — yet this is where user complaints concentrate in Trustpilot / Reddit reviews.
- **Watermark removal is quietly becoming a feature.** Smodin exposes it as an API flag; most other vendors imply it. Google SynthID, OpenAI watermarking, and C2PA provenance will turn this into either (a) a regulatory liability or (b) the next competitive moat — no consensus yet.

## Sources

- [Nerdbot — Best AI Humanizers That Work in 2026 (April 2026)](https://nerdbot.com/2026/04/12/best-ai-humanizers-that-work-in-2026-a-rigorous-evaluation-of-undetectable-text-rewriters/) — most rigorous independent comparative evaluation; per-vendor pricing, API schemas, privacy posture.
- [Humaniser — Best AI Humanizer 2026 rankings](https://humaniser.com/blog/best-ai-humanizer-2026) — vendor-published but cites per-detector bypass numbers (93% Humaniser, 86% Undetectable AI, 74% StealthGPT, 69% HIX Bypass).
- [aixradar — 7 AI humanizers tested against GPTZero](https://aixradar.com/best-ai-text-humanizer/) — independent head-to-head GPTZero testing.
- [Humanizer AI — 10 tools tested and ranked, 2026](https://humanizerai.com/blog/best-ai-humanizer-2026) — cross-tool bypass comparison including Humbot, StealthWriter, Phrasly.
- [TwainGPT — Humanize AI review](https://www.twaingpt.com/blog/humanize-ai-review/) — concrete per-detector results showing marketing vs reality gap.
- [Undetectable.ai Developer API docs](https://help.undetectable.ai/en/article/developer-api-1fvasec/) — `readability` / `purpose` / `strength` / `model` parameters.
- [Undetectable.ai Wikipedia entry](https://en.wikipedia.org/wiki/Undetectable.ai) — founding narrative, May 2023 launch.
- [Reuters — Undetectable AI surpasses 15M users (Feb 2025)](https://www.reuters.com/press-releases/undetectable-ai-surpasses-15-million-users-2025-02-06/) — vendor press release figure; subsequent Tracxn/G2 profiles show ~11M as of 2026. [Latka — Undetectable AI revenue](https://getlatka.com/companies/undetectable.ai) — $3.7M ARR, ~34 employees, Sep 2025.
- [WriteHuman API docs](https://writehuman.ai/api/docs) and [AI Humanizer API pricing](https://aihumanizerapi.com/pricing/) — REST endpoint, Bearer auth, per-1K-word economics.
- [HIX Bypass API guide](https://explinks.com/blog/how-to-get-hix-bypass-api-key-step-by-step-guide) — endpoint structure, 2K-word/request cap.
- [Phrasly API docs](https://phrasly-api.readme.io/reference/introduction) — current endpoints (Detector + Balance; humanizer endpoint noted "in development").
- [Rephrasy API solution](https://www.rephrasy.ai/api-solution) — v3 / Undetectable v2 / SEO model options and credit pricing.
- [Humanizer.org pricing](https://humanizer.org/pricing), [Humbot pricing](https://humbot.ai/pricing), [Conch AI pricing](https://www.getconch.ai/pricing), [ZeroGPT pricing](https://www.zerogpt.com/pricing), [AIHumanizerPro pricing](https://www.aihumanizerpro.ai/pricing), [HumanizerAI.com pricing](https://humanizerai.com/pricing), [Humanize AI (.io) pricing](https://www.humanizeai.io/pricing/), [Humanize AI (.com) pricing](https://humanizeai.com/pricing/), [Smodin signup/pricing](https://smodin.io/app/id/signup), [Spinbot pricing via Rephrasely review](https://rephrasely.com/blog/spinbot-review-2026-features-pricing-honest-verdict).
- [Surfer SEO humanizer review](https://thehumanizeai.pro/articles/surfer-seo-humanizer-review-2026) — 76% vs 99.2% dedicated-humanizer gap.
- [Content at Scale bypass analysis (Humanizer PRO)](https://texthumanizer.pro/bypass/content-at-scale) — 67% → 6% detection after humanization.
- [Scribbr AI Humanizer page](https://www.scribbr.com/ai-humanizer/) and [bypass analysis](https://humaniser.com/bypass-scribbr).
- [Grammarly AI Humanizer](https://www.grammarly.com/ai-humanizer).
- [Jasper Brand Voice](https://www.jasper.ai/brand-voice).
- [Writesonic AI Text Humanizer docs](https://docs.writesonic.com/docs/ai-text-humanizer).
- [Copy.ai Free AI Humanizer](https://www.copy.ai/tools/free-ai-humanizer).
- [TextCortex pricing](https://textcortex.com/pricing).
- [Rewritely — 12 tools tested 2026](https://rewritelyapp.com/blog/best-ai-humanizers-2026-comparison-test) and [TextToHuman 2026 review](https://marketspur.com/texttohuman-com-review-features-pricing-real-results/).
- [Medium (Hayim Salomon, April 2026) — the arms race is unwinnable](https://medium.com/@hayimsalomon/the-arms-race-between-ai-detectors-and-humanizers-is-unwinnable-heres-what-we-should-do-instead-ec8a1d94a129).
- [Supwriter — AI Humanizer Market 2026](https://supwriter.com/blog/ai-humanizer-market-2026) and [QYResearch Bypass AI Detector market forecast](https://www.qyresearch.com/reports/6240618/bypass-ai-detector-tool) — market sizing and CAGR.
- [Data Science Collective (Medium, Feb 2026) — The engineering behind AI humanization systems](https://medium.com/data-science-collective/the-engineering-behind-ai-humanization-systems-4cf2b597dedb) — perplexity/burstiness technique explainer.
- [UndetectedGPT — 7 techniques to rewrite AI text (2026)](https://www.undetectedgpt.ai/blog/how-to-rewrite-ai-text) and [Why AI Humanizers Don't Work](https://thehumanizeai.pro/blogs/why-ai-humanizers-dont-work-and-what-does) — technique taxonomy; 12-of-14-tools-fail finding.
