Duet Air vs HTML Previewer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Duet Air
Transform your iPad or iPhone into an advanced remote desktop or an extra display for your Mac or PC. Experience unparalleled performance and zero lag, with touch and gesture support. Offers professional-grade drawing capabilities with Apple Pencil integration for artists and designers.
- Remote desktop functionality
- Extra display for Mac/PC
- Touch and gesture support
- Apple Pencil integration for drawing
- Wireless and wired connectivity
- Zero lag performance
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#1 best-selling iPad app in US, Japan, UK, Germany, and 17 other countries! Duet turns your iPad or iPhone into the most advanced Remote Desktop or extra display for your Mac & PC. Developed by a team of ex-Apple engineers, Duet offers unparalleled performance and display quality - all with zero lag. — DO MORE — Be twice as productive by multitasking with two screens. And for those that travel, have a portable way to stay productive. — INCREDIBLY SIMPLE — To get started, plug your iPad into your desktop using your charging cable or choose the desktop to wirelessly connect to. The Duet desktop app will automatically detect your device, and transform it into a high performance touchscreen display. — TOUCHSCREEN — Interact with Mac & PC like never before, with touch & gestures, including two-finger scrolling, pan and zoom. And with our latest release, you can even add a touch bar to any iPad with any Mac. — PERFECT FOR APPLE PENCIL — With Duet Pro, you can turn your iPad and Apple Pencil into a professional graphics tablet. We’ve re-engineered our rendering algorithms for ultra-responsive drawing, optimized specifically for designers, illustrators and artists. Duet Pro also unlocks pressure & tilt sensitivity, hover, palm rejection, and more to seamlessly draw in the most powerful programs for professionals. Get precise control in Photoshop, Corel Painter, Lightroom, ToonBoom, Illustrator, Manga Studio and more. — PRESS — TechCrunch - "Feels Like Magic" TIME - "Getting Work Done Faster and More Efficiently" The Guardian - "Lag-free" Forbes - "The simple thing to note is this...Duet Display works." The Verge - "Glorious Fluidity" Lifehacker - "It's fast, easy to use, and works great" Business Insider - "Zero lag and true retina resolution” Wall Street Journal - “It’s as easy as just plugging it in" — REVIEWS — “Awesome! My iPad Pro can be an extra monitor! Cool app” ~CEO of T-Mobile, John Legere “Very smooth and responsive indeed, plus you could use the touch screen to “click” on screen interfaces!” ~Photographer, Lok Cheung “Love the ability to use my iPad as a monitor with Duet.” ~Former Chief Evangelist of Apple, Guy Kawasaki “Just started using this app called Duet… Kinda love it so far.” ~Comedian and Youtube, Phillip DeFranco “All my mac folks look at the Duet app… GREAT!” ~Actor and Comedian, Sinbad "I really like the app, I suppose the biggest compliment I can give is that it's so easy to setup it almost seems like an Apple product.” ~Early Adopter, M. Nightingale "Amazing solution for me by the way. Works as I was hoping for and actually my main reason for getting an iPad : )” ~Early Adopter, M. Gemzoe Duet Works With: All iPhones and iPads with iOS 11.0 and later All Macs with 10.11 (Mavericks) and later All PCs with Windows 10 64-bit and later Duet Air is a $24.99 per year service built for professionals and remote workers. Price may vary by location. Duet Air subscriptions will be charged to your credit card through your iTunes account. Your subscription will automatically renew unless canceled at least 24 hours before the end of the current period. You will not be able to cancel the subscription once activated. Manage Duet Air in Account Settings after the optional upgrade. Learn more at http://www.duetdisplay.com Terms: https://help.duetdisplay.com/duet-terms-services Privacy Policy: https://help.duetdisplay.com/duet-privacy-policy
HTML Previewer
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Open received HTML and ZIP reports, read Markdown notes, and inspect JSON or YAML on iPhone and iPad. Files are processed on your device. Read the content, keep the formatting - View HTML layouts, graphics, and animations. - Read Markdown tables and highlighted code, with one-tap code copying. - Display Markdown math equations and Mermaid diagrams offline. - Browse HTML and Markdown pages inside ZIP reports with local CSS and image assets. - Search within HTML and Markdown, navigate headings, adjust reading appearance, and reopen at your saved reading position. Inspect JSON and YAML - Expand nested objects and arrays, search fields and values, and check highlighted source with line numbers. - Copy values or field paths and jump to the corresponding source line. - View and copy large JSON numeric IDs without rounding their digits. - Locate syntax errors by line and column. YAML also supports multiple documents. Import, organize, and share - Open files from Files, Mail, AirDrop, messaging apps, cloud drives, or other apps. Open/share menu availability depends on iOS and the source app. - Select multiple documents or ZIP packages. Update duplicates, keep both copies, or skip individual files, then review import results. - Paste HTML, Markdown, JSON, or YAML text to create a local preview. - Find saved files by filename, pin frequent documents, and rename display titles. - Share original files or complete ZIP packages. Export HTML and Markdown previews as PDF. - Try the built-in HTML, Markdown, JSON, YAML, and ZIP samples. Supported extensions: .html, .htm, .md, .markdown, .json, .yaml, .yml, and .zip. JSON and YAML previews are read-only and share the original file. JSONC comments and trailing commas are not supported. PDF export is available for HTML and Markdown. Privacy and purchase Files are processed on device; the app does not upload your files. No account or ads. Paid download with no subscription or in-app purchase. New HTML files, including HTML inside ZIP packages, open in Interactive mode with page JavaScript and external resources enabled. The HTML content can make network requests. Select Safe Preview to block page scripts and external HTTP/HTTPS resources. External navigation and form navigation remain blocked in both modes. Saved preview choices are preserved when reopening files.
Screenshots
Verdict
The clearest difference is price: Duet Air at Free against HTML Previewer's $5.99. Duet Air also leads on iOS requirement (12.0 vs 17.0). HTML Previewer's advantage is in-app purchases (none vs 2) and ads (none vs shown). On device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Duet Air is free to download; HTML Previewer costs $5.99 up front. Duet Air sells 2 in-app purchases, starting at $49.99 per year. HTML Previewer asks for nothing beyond the download.
Duet Air ships an update every 3 weeks, HTML Previewer every 4 days. The most recent releases landed on October 18, 2026 and October 11, 2026 respectively.
| Parameter | Duet Air | HTML Previewer |
|---|---|---|
| Price | Free — better | $5.99 |
| Rating | 4.3 (1.9K ratings) — better | — |
| Positive reviews | 23.8% of reviews | — |
| Number of ratings | 1.9K — better | — |
| Update frequency | Every 3 weeks | Every 4 days — better |
| Ads | Yes | No — better |
| In-app purchases | Yes | No — better |
| Monetization | Subscription | — |
| Best chart rank | — | #192 — better |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 12.0 — better | 17.0 |
| Further details — not scored | ||
| Size | 67 MB | 9 MB |
| Age rating | 4+ | 4+ |
| Developer | Duet, Inc. | SHIFENG ZHANG |
Bugs and requests
Duet Air
Reported bugs
5 issues- Incompatible with Citrix
- Breaks Windows network
- Bricked user's PC
- Login screen issues
- Inconsistent performance
Requested features
5 requests- Support for older devices
- Improve wireless stability
- Add audio support
- Better integration with drawing apps
- Easier subscription cancellation
HTML Previewer
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Duet Air
- Duet Air (Annual)7 Days trial$49.991 Year
- Duet Pro (Annual)7 Days trial$79.991 Year
HTML Previewer
No in-app purchases









