Undetectable AI vs Passed.AI – Comparison & Alternatives

Undetectable AI

Detect AI-generated content for free and humanize it so it passes every major AI checker — trusted by 22 million users worldwide.

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Passed.AI

The only academic integrity tool that shows you exactly how a document was written — Passed.AI's Replay Tool, Document Audit, Flow Score, and Originality.ai-powered detection give educators complete writing process visibility for $9.99/month with unlimited scans.

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Quick Comparison: Undetectable AI vs Passed.AI

A high-level overview of pricing, key strengths, and use cases to help you choose the right tool fast.

Features

Undetectable AI

Passed.AI

Quick View

Undetectable AI is an AI detection and humanization platform co-founded in January 2023 by Christian Perry and Devan Leos, headquartered in Boise, Idaho. The tool…

Passed.AI is an educator-focused academic integrity platform co-founded in 2022 by Andrew Rains through Fractional SAAS Inc. (Canada). It provides AI Detection and Plagiarism Checking…

Pricing

Freemium: Starting at $14.99/mo

Freemium: Starting at $9.99/mo

Key Strength

• Multi-Model AI Detector (Free) — Checks your text against 8 major AI detectors at once — including GPTZero, Originality.ai,…

• Replay Tool — Watch exactly how a student wrote their document at adjustable playback speed; see every keystroke, deletion,…

Best For

Undetectable AI works best for anyone producing or evaluating AI-assisted content who needs fast, affordable detection and humanization in one…

Passed.AI is purpose-built for educators, academic institutions, and students navigating academic integrity disputes — not for content marketers, SEO professionals,…

Detailed Feature Breakdown

Go deeper into the specific capabilities, pros, cons, and integrations of both platforms.

Features

Undetectable AI

Passed.AI

Overview

Undetectable AI is an AI detection and humanization platform co-founded in January 2023 by Christian Perry and Devan Leos, headquartered in Boise, Idaho. The tool gives you a permanently free multi-model AI detector that checks text against 8 major detectors simultaneously, plus a paid humanizer that rewrites AI-generated content to pass GPTZero, Turnitin, Copyleaks, and Originality.ai. With over 22 million users and 50+ language support, it is one of the most widely used AI content tools globally.

Passed.AI is an educator-focused academic integrity platform co-founded in 2022 by Andrew Rains through Fractional SAAS Inc. (Canada). It provides AI Detection and Plagiarism Checking powered by Originality.ai, a writing process Replay Tool, Document Audit with Paste-In Analysis, Revision Tracking, Flow Score, Contribution Analysis, Time Investment Assessment, and a Chrome Extension for Google Docs.

It also offers Academic Honesty Reports for students wrongly accused of AI use. Pricing is $9.99/month for unlimited scans with 200 included credits, plus a 14-day free trial. AI detection is English-only; the Document Audit and Replay Tool work in all languages.

Key Features

• Multi-Model AI Detector (Free) — Checks your text against 8 major AI detectors at once — including GPTZero, Originality.ai, Copyleaks, and ZeroGPT — delivering a consolidated human score instantly with no account or signup required.

• AI Humanizer with Writing Level Matching — Rewrites AI-generated text at your chosen reading level (Elementary, High School, College, PhD, or Custom) so the output naturally fits your target audience without manual editing.

• Chrome Extension — Brings detection and humanization directly into Google Docs, Gmail, social media platforms, and any webpage, letting you humanize content without switching tabs.

• Smart Job Applier — Automatically generates tailored cover letters and job application responses that read as naturally human-written, optimized to avoid AI flags from employer screening tools.

• Human Auto Typer — Simulates authentic keyboard input behavior to produce text that bypasses behavioral AI detection systems that analyze typing patterns in addition to content.

• 50+ Language Support — Detects and humanizes content in over 50 languages with multilingual AI detection and rewriting, with English offering the highest verified accuracy.

• Money-Back Guarantee — If any humanized output is flagged as AI-generated by a covered detector, Undetectable AI refunds the cost of that humanization — a unique confidence guarantee in the market.

• Business API — Available on custom Business plans; enables developers and enterprise teams to programmatically submit text for detection and humanization at production scale with resale, support, and customization options.

• Replay Tool — Watch exactly how a student wrote their document at adjustable playback speed; see every keystroke, deletion, paste, and revision in chronological sequence; the only tool in the reviewed academic integrity market that provides full writing visualization rather than a static score.

• Document Audit — Comprehensive per-document report including AI Reliance Score, Plagiarism Score, Paste-In Analysis (all pasted content with timing and source), Revision Tracking (detailed change history with timestamps), Flow Score (natural writing progression vs. AI insertion patterns), Contribution Analysis (individual inputs in collaborative documents), and Time Investment Assessment (duration spent on the document).

• AI Detection (Powered by Originality.ai) — Originality.ai is partnered directly into the Passed.AI platform for best-in-class AI detection accuracy; trained on ChatGPT, GPT-2, GPT-3, GPT-J, and GPT-4 outputs; returns sentence-level Human vs. AI probability scores; English only.

• Plagiarism Check (Powered by Originality.ai) — Identifies non-cited passages against external online sources; returns specific source matches; integrated into the same Document Audit report as AI detection for a unified submission review.

• Chrome Extension (Google Docs Integration) — Integrates Passed.AI's full Document Audit directly into Google Docs; enables in-app analysis without exporting documents to an external dashboard; the primary workflow path for educators using Google Workspace.

• Academic Honesty Reports — Students wrongly accused of AI use can submit their documents to Passed.AI for a formal, evidence-backed report using the same Document Audit and Replay Tool that educators use — providing a documented defense mechanism accessible directly through the platform.

• Credits System (Pay-As-You-Go) — Each subscription includes 200 credits per month that roll over and never expire; each credit covers up to 200 words at one cent per credit; credits unlock advanced AI detection and plagiarism scan features beyond the base unlimited scans included in the subscription.

• Flow Score — Measures the natural progression and coherence of writing within a document to distinguish organic human drafting patterns from AI-generated content blocks inserted in unnatural uniformity — a secondary check layer that reduces false positives from stylistically consistent human writers.

Pros

Permanently free AI Detector with no signup required checks text against 8 major detectors simultaneously in one click
Forbes-nominated best AI detector; independently validated at 100% accuracy in a 2024 peer-reviewed study in the Indian Journal of Psychological Medicine
Yearly plan starts at $5/month billed annually (6 months free included) — one of the most affordable humanizer subscriptions available in 2026
Money-back guarantee covers any humanized output that gets flagged, removing financial risk from the paid plan
50+ language support for both detection and humanization — broader multilingual coverage than most direct competitors
Chrome Extension enables detection and humanization inside Google Docs, Gmail, and social media without switching apps
Smart Job Applier is a unique value-add that no direct AI humanizer competitor currently offers

Replay Tool is unique in the academic integrity market — watch the full document writing process at adjustable speed; no other reviewed tool provides live writing visualization at any price point
Originality.ai partnership delivers best-in-class AI and plagiarism detection accuracy without Passed.AI needing to maintain a proprietary detection engine
Document Audit secondary checks (Paste-In Analysis, Flow Score, Revision Tracking, Time Investment) significantly reduce false positives and false negatives versus single-score detection tools
$9.99/month for unlimited scans is dramatically more affordable than Turnitin's institutional per-seat pricing for comparable academic integrity functionality
Chrome Extension integrates directly with Google Docs — the dominant writing platform in K-12 and higher education — enabling real-time monitoring without document exports
Academic Honesty Reports for students create a dual-purpose platform that serves both detection and defense — addressing the student fairness concern that most academic integrity tools ignore
Credits roll over and never expire — unused credits accumulate across months, providing budget flexibility for irregular detection workloads
14-day free trial with full feature access and no credit card required

Cons

Free humanizer trial is only 250 words over 3 days — not enough to evaluate output quality on real content before committing to a paid plan
Bypass success rates against Originality.ai's Turbo model are inconsistent, with some users reporting 70-85% human scores rather than the claimed 100%
All paid plans offer the same feature set — the only difference is word count and billing cycle, giving power users no premium tier with advanced controls
Word counts on monthly plans reset each cycle with no rollover, so unused words are lost and occasional users overpay for idle credits
No native WordPress plugin or CMS integration — all humanization requires either the web app or Chrome Extension manually
The Smart Job Applier and Human Auto Typer raise ethical transparency concerns when used in academic submissions or professional hiring contexts

AI Detection and Plagiarism Checking are English-only — the Originality.ai engine is not trained on non-English languages, limiting the platform for educators in multilingual classrooms or international institutions
No API integration — documents must be submitted via the web dashboard or Chrome Extension; no programmatic bulk processing for institutions with high-volume automated review workflows
Requires Google account login — no email/password registration option, creating a dependency on Google authentication that may create friction in non-Google Workspace institutions
Limited payment methods — third-party reviewer confirms reduced accessibility due to narrow payment options versus credit card and PayPal standard coverage
No live chat support — the absence of real-time support is a gap for educators dealing with urgent academic misconduct cases requiring immediate platform assistance
Credits system adds billing complexity — determining credit costs per feature requires consulting the pricing documentation rather than a flat-rate all-inclusive subscription
Document Audit and Replay Tool require the Chrome Extension for real-time Google Docs integration — users on non-Chrome browsers or non-Google Docs platforms must use the manual paste-and-scan workflow

Best For

Undetectable AI works best for anyone producing or evaluating AI-assisted content who needs fast, affordable detection and humanization in one place.

• Content marketers and SEO bloggers — process AI-drafted articles through the humanizer before publishing to ensure they pass detector audits and maintain authentic readability for both readers and Google.

• Students and academics — use the free multi-model detector to self-check essays and assignments before submission; users are solely responsible for complying with their institution's academic integrity policies.

• Freelance writers and copywriters — speed up client deliverables by drafting with AI tools and humanizing the output in seconds, preserving their personal voice and meeting client AI-free content requirements.

• Job seekers and recruiters — use the Smart Job Applier to generate cover letters and application materials that read as genuinely human and do not trigger AI screening tools used by employers.

• Developers and enterprise content teams — integrate detection and humanization at scale via the Business API, with resale and customization options for building humanization into existing publishing pipelines.

Passed.AI is purpose-built for educators, academic institutions, and students navigating academic integrity disputes — not for content marketers, SEO professionals, or general AI writing workflows.

• Teachers and university professors — use the Document Audit and Replay Tool to evaluate submitted assignments with full writing process visibility; the secondary checks (Paste-In Analysis, Flow Score, Revision Tracking) provide defensible, context-rich evidence for academic misconduct conversations rather than a single contestable percentage score.

• Academic institutions and departments — the $9.99/month flat-rate unlimited scan pricing makes Passed.AI accessible for individual educators without institutional procurement; the Chrome Extension integrates into existing Google Workspace environments with no IT infrastructure change.

• K-12 schools using Google Classroom — the Chrome Extension's Google Docs integration is optimized for the Google Workspace for Education environment dominant in K-12, making Passed.AI the most frictionless AI integrity tool for this specific technology stack.

• Students wrongly accused of AI use — Academic Honesty Reports provide formal, evidence-backed documentation of genuine human authorship using the same tools educators use, giving students an accessible professional-grade response to false positive accusations.

• Academic integrity officers and department heads — the Contribution Analysis feature for collaborative documents, combined with timestamped Revision Tracking and the Replay Tool, provides the level of documented, timestamped evidence required for formal academic misconduct proceedings.

Pricing Details

Free Tier ($0): 250-word humanizer credit (3-day trial), AI Humanizer access, free AI Detector (unlimited, no signup), Smart Job Applier access, Human Auto Typer, multi-language support.

Yearly Plan (from $5/mo billed annually): Starts at 10,000-15,000 words/month (scales up to 300,000+), all core features including AI Humanizer, AI Detector, Smart Job Applier, Human Auto Typer, Chrome Extension, writing level matching, money-back guarantee, 6 months free included with annual commitment.

Monthly Plan (from $14.99/mo): Starts at 15,000 words/month (scales up to 380,000+), all core features including AI Humanizer, AI Detector, Smart Job Applier, Human Auto Typer, Chrome Extension, writing level matching, money-back guarantee, cancel anytime, no annual commitment required.

Business Plan (Custom pricing): Unlimited Human Auto Typer, AI Detector, Smart Job Applier, full API access with resale and customization, non-expiring bulk credits, redistribution options, priority support, dedicated account management.

Free Trial (14-Day, No Credit Card Required): Full access to all features including Document Audit, Replay Tool, AI Detection (Originality.ai), Plagiarism Check, Flow Score, Chrome Extension, and Academic Honesty Reports. No usage limitations stated during the trial period. Best for educators evaluating the platform before committing to a paid subscription.

Pro ($9.99/mo — Unlimited Scans): Unlimited document scans, access to the full suite of features (Document Audit, Replay Tool, History Report, AI Detection, Plagiarism Check, Chrome Extension, Academic Honesty Reports), 200 credits included per month. Credits roll over and never expire.

Credits System (Pay-As-You-Go add-on): Each credit costs $0.01 and covers up to 200 words. Scanning a 200-word document for AI detection plus plagiarism costs 2–4 credits depending on chosen advanced tools. Credits are purchased in addition to the standard subscription when the 200 monthly included credits are exhausted. Institutional and bulk credit pricing: contact Passed.AI directly for volume discounts.

Unique Features

Undetectable AI differentiates itself through its permanently free multi-model detector, a money-back humanization guarantee, and job application tools that no other AI humanizer offers.

• 8-Detector Simultaneous Scoring (Free, No Signup) — Rather than checking against a single detector, the free tool runs your text through GPTZero, Originality.ai, Copyleaks, ZeroGPT, and four other major models at once, giving you a complete picture of how your content will perform across the detectors your audience actually uses.

• Money-Back Humanization Guarantee — If the humanized output still gets flagged as AI-generated by a covered detector, Undetectable AI refunds the cost of that specific humanization — the only guarantee of its kind in the AI humanizer market, making the paid plan effectively risk-free.

• Writing Level Matching — The humanizer lets you specify the exact reading level (Elementary through PhD or Custom) so the rewritten text naturally fits your specific audience, not just a generic human-sounding output.

• Smart Job Applier — A built-in tool that automatically drafts AI-undetectable cover letters and job application responses tailored to specific job descriptions — a completely unique feature that no direct AI humanizer competitor currently offers.

• Human Auto Typer — Simulates authentic keyboard behavior patterns in addition to rewriting content, helping users bypass behavioral detection systems that analyze how text was typed, not just what it says.

Passed.AI's differentiators are the Replay Tool, the Document Audit's multi-layer secondary checks, the Academic Honesty Report for students, and the Originality.ai partnership — creating the only academic integrity platform that addresses both institutional detection and student defense in one subscription.

• Replay Tool (Writing Process Visualization) — No other reviewed academic integrity or AI detection tool allows educators to literally watch a document being written. The Replay Tool plays back every keystroke, paste event, deletion, and revision at adjustable speed — transforming the adjudication conversation from 'your AI score was 87%' to 'here is the documented evidence of exactly how this document was created.' This shifts the burden of proof from contested percentages to observable behavior, which is fundamentally more defensible in a formal academic misconduct process.

• Document Audit Multi-Layer Secondary Checks — The combination of AI Reliance Score, Plagiarism Score, Paste-In Analysis, Flow Score, Revision Tracking, Contribution Analysis, and Time Investment Assessment in a single report is unique in the market. Single-metric tools (GPTZero, Copyleaks, Winston AI) return one number; Passed.AI returns a contextualized behavioral profile of how the document was created — dramatically reducing false positive risk.

• Academic Honesty Report (Student Defense Tool) — Passed.AI is the only reviewed academic integrity platform that builds an explicit student-side service: providing formal, evidence-backed reports for students facing wrongful AI accusations. This dual institutional/student positioning is unique in the category and directly addresses the AI detection fairness concern raised by academic researchers and covered in major press including NPR and NBC News.

• Originality.ai Partnership (Detection Accuracy) — Rather than maintaining a proprietary detection engine (which requires continuous retraining as LLMs evolve), Passed.AI partners with Originality.ai — the provider independently rated as the highest-accuracy AI detector in the market. This partnership gives Passed.AI access to state-of-the-art detection accuracy without the engineering overhead of maintaining a competing detection model.

Integrations

Undetectable AI is browser-based with a Chrome Extension and Business API, covering the most common content creation and publishing environments.

• Web App (undetectable.ai) — Fully browser-based dashboard accessible on any modern desktop or mobile browser; paste text or upload content for instant detection and humanization with no installation required.

• Chrome Extension — Integrates directly into Google Docs, Gmail, LinkedIn, social media platforms, and any webpage; run AI detection and humanization without leaving your current tab or copying text into a separate tool.

• Business API — Available on custom Business plans; REST-based integration for developers and enterprise teams to submit text programmatically for detection and humanization at scale, with resale, redistribution, and customization support.

• GPTZero, Originality.ai, Copyleaks, ZeroGPT, Turnitin (Detection Targets) — The platform is specifically tested and optimized against these eight detectors, so humanized output is calibrated to pass the scanners your editors, professors, or clients actually use.

• 50+ Languages — Multilingual detection and humanization are supported natively across all plans; English delivers the highest accuracy, with broad functional coverage across Latin-script and other major world languages.

Passed.AI is a web app with a Chrome Extension — optimized for Google Workspace for Education environments and accessible on any modern browser through the dashboard.

• Web App (passed.ai) — Fully browser-based dashboard accessible on any modern desktop browser (Chrome, Firefox, Safari, Edge); paste-and-scan interface for AI detection, plagiarism checking, and Document Audit without Google Docs; suitable for non-Google Workspace institutions.

• Google Chrome Extension (Google Docs Integration) — The primary integration path for K-12 and higher education Google Workspace environments; integrates the full Document Audit (AI Detection, Plagiarism Check, Paste-In Analysis, Revision Tracking, Flow Score, Replay Tool) directly into the Google Docs interface; monitors document writing in real-time without requiring manual exports.

• Google Docs (Full Native Integration) — The platform is specifically designed around Google Docs as the primary document environment; Document Audit features including Contribution Analysis, Time Investment Assessment, and Replay Tool leverage Google Docs' native version history and collaboration metadata for maximum data richness.

• Originality.ai (Detection Engine Partnership) — AI Detection and Plagiarism Checking are powered by Originality.ai's proprietary engine, trained on ChatGPT, GPT-2, GPT-3, GPT-J, and GPT-4 outputs; English language only; returns sentence-level probability scores embedded within the Passed.AI Document Audit report.

• All Languages (Document Audit and Replay Tool) — The Document Audit, Replay Tool, History Report, Paste-In Analysis, Revision Tracking, Flow Score, and Contribution Analysis features work regardless of document language; only AI detection and plagiarism checking are limited to English content due to the Originality.ai engine's training scope.

Alternatives

Originality.ai

Freemium: Starting at $14.95/mo

BypassGPT

Freemium: Starting at $8/mo

WriteHuman AI

Freemium: Starting at $12/mo

BypassAI.io

Freemium: Starting at $4.14/mo

Undetectable AI

Freemium: Starting at $14.99/mo

GPTinf

Freemium: Starting at $9.99/mo

Frequently Asked Questions

Which is better, Undetectable AI or Passed.AI?

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What does Undetectable AI do better than Passed.AI?

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Can I use Undetectable AI and Passed.AI together?

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Is Undetectable AI or Passed.AI better for beginners?

Do Undetectable AI and Passed.AI offer free plans?

Which has better support, Undetectable AI or Passed.AI?

Expert Verdict

Final Analysis: Which is better?

The honest verdict: Undetectable AI excels for Undetectable AI works best for anyone producing or evaluating AI-assisted content who needs fast, affordable. at Freemium: Starting at $14.99/mo. Passed.AI is stronger for Passed.AI is purpose-built for educators, academic institutions, and students navigating academic integrity disputes — not. at Freemium: Starting at $9.99/mo. The AI tool category has room for both — your decision should be driven by which specific capabilities matter most to your team in 2026.

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Chosen by 2M+ students and writers, BypassAI.ai delivers a 99.7% pass rate across GPTZero, Turnitin, Originality.ai, ZeroGPT, Winston AI, Content at Scale, and Copyleaks — with three humanization modes, a built-in tri-detector AI Checker, ChatGPT watermark removal, and 30+ language support from $6.99/month.

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Undetectable AI

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Quick Comparison: Undetectable AI vs Passed.AI

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Final Analysis: Which is better?

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