AI answer engine with real-time web search and cited sources.
Merlin AI vs Undetectable AI
Features, pricing, strengths and trade-offs — and which one fits your situation.
The verdict
Summary
Merlin AI is best for using multiple AI models on any web page through a browser extension, while Undetectable AI is best for checking text against multiple AI detectors and rewriting flagged passages. Only Merlin AI offers answers with citations. Merlin AI has a free plan, while Undetectable AI offers a free trial.
Which should you choose?
Choose Merlin AI if…
- You need using multiple AI models on any web page through a browser extension
- Answers with citations matters to you
- You're one of: knowledge workers who live in the browser, students summarizing videos and articles, professionals drafting emails and linkedin posts
- You want a free plan (Undetectable AI only has a trial)
Choose Undetectable AI if…
- You need checking text against multiple AI detectors and rewriting flagged passages
- You're one of: content marketers polishing ai-assisted drafts, writers checking how their text may be scored by detectors, agencies needing an api
- Detect, rewrite and re-check workflow in one place
At a glance
| Merlin AI | Undetectable AI | |
|---|---|---|
| Best for | Using multiple AI models on any web page through a browser extension | Checking text against multiple AI detectors and rewriting flagged passages |
| Free plan | Yes | Trial only |
| Starting price | From $19/mo | From $5/mo |
| Learning curve | Low | Low |
| Platforms | Web, iOS, Android, Chrome extension | Web, Chrome extension, API |
| Ideal for | Knowledge workers who live in the browser, Students summarizing videos and articles, Professionals drafting emails and LinkedIn posts | Content marketers polishing AI-assisted drafts, Writers checking how their text may be scored by detectors, Agencies needing an API |
Feature comparison
| Merlin AI | Undetectable AI | |
|---|---|---|
| Answers with citations | Yes | No |
| Searches academic papers | — | No |
| Upload & chat with PDFs | Yes | — |
| AI content detection | Yes | Yes |
| Rewrites / humanizes text | Yes | Yes |
| Citation formatting | — | — |
| Browser extension | Yes | Yes |
| Writing editor | — | — |
IncludedLimited / higher plansNot available— Not confirmed
Security & enterprise
| Merlin AI | Undetectable AI | |
|---|---|---|
| Business / enterprise plan | Yes | Yes |
| SSO (SAML / OIDC) | Enterprise plan | — |
| SCIM user provisioning | Enterprise plan | — |
| SOC 2 | Type II | — |
| ISO 27001 | Yes | — |
| HIPAA (BAA available) | — | — |
| GDPR DPA | Enterprise plan | — |
| Data residency options | — | — |
| No training on your data | Yes | — |
| Audit logs | — | — |
| Admin controls | Yes | — |
| Deployment | Cloud | Cloud |
From each vendor's security documentation. "—" = not confirmed. What to ask vendors · Compare all tools
What each tool does
Merlin AI
Merlin AI is a browser extension and web app that gives access to many AI models (from OpenAI, Anthropic, Google and others) in one place. It summarizes web pages and YouTube videos, helps write emails and posts inside Gmail and LinkedIn, and chats with uploaded files. It also bundles tools such as an AI detector and humanizer.
Key features- Chrome extension that opens an AI sidebar on any page
- Access to multiple models from different providers
- YouTube and web page summaries
- Gmail and LinkedIn writing assistance
- Chat with PDFs and other uploaded files
- AI detector and AI humanizer tools
Undetectable AI
Undetectable AI combines an AI detector that aggregates predictions from several third-party detectors with a humanizer that rewrites AI-generated text. It also offers a Chrome extension, an API and a set of writing tools. It is used by content writers and marketers, and is also marketed to students, where undisclosed AI use may breach academic rules.
Key features- AI detector showing likely results across several popular detectors
- Humanizer with modes such as Quality, Balanced and Creative
- Chrome extension that works in Gmail, Google Docs, LinkedIn and other sites
- Auto-typer tool for Google Docs
- API and Zapier integration
- Additional writing tools such as paraphraser and AI writer
Pricing
Merlin AI
Free plan; Pro ~$19/mo, cheaper annually
Undetectable AI
Free trial (250 words); paid from $5/mo billed annually (10k words/mo)
Prices last checked September 2026. Plans change often — confirm on each vendor's site.
Pros and cons
Merlin AI
Strengths- One subscription covers several providers' models
- Works inside the sites you already use
- Free plan with daily queries
- Also available on iOS and Android
- Top models are limited or reduced on the free plan
- Query-based limits can run out quickly with premium models
- Browser extension requires broad page access permissions
- Not a dedicated academic research tool; no specialized paper database
Not ideal for: Researchers who need rigorous academic sourcing should use Consensus, Elicit or Scite instead.
Undetectable AI
Strengths- Detect, rewrite and re-check workflow in one place
- Detector gives a view across multiple third-party checkers
- Extension works inside many common writing sites
- API available for businesses
- Free option is only a small trial
- Humanized output can read awkwardly and needs manual editing
- Auto-typer and humanizer features can be used to disguise AI work, which may breach academic integrity policies
- Detector results are estimates and can produce false positives
Not ideal for: Students should not use it to pass off AI-generated work as their own; it offers no research, source-finding or citation features.
Integrations
Merlin AI
Undetectable AI
FAQ
What is the main difference between Merlin AI and Undetectable AI?
Merlin AI is built for using multiple AI models on any web page through a browser extension; Undetectable AI is built for checking text against multiple AI detectors and rewriting flagged passages. Key differences: Merlin AI offers answers with citations.
Is Merlin AI or Undetectable AI cheaper?
Merlin AI starts from $19/mo and Undetectable AI starts from $5/mo (as of September 2026). On entry price, Undetectable AI is cheaper — but compare what each plan includes, since limits differ. Always confirm current pricing on each vendor's site.
Do Merlin AI and Undetectable AI have free plans?
Merlin AI has a free plan, while Undetectable AI offers a free trial.
Which is easier to use, Merlin AI or Undetectable AI?
Both have a low learning curve.
What are good alternatives to Merlin AI and Undetectable AI?
Other research & study tools worth comparing include Perplexity, Consensus and Monica.
