Every viewport, exactly right
Pages render at each device's true width — layouts wrap, break and reflow just like real life, with live pixel readouts. Pinch to zoom, rotate to landscape.
Every device size.
On the go.
Open any URL at true iPhone, iPad and Mac viewports — straight from your iPhone or iPad, wherever you are. Real layouts at real widths, not a scaled screenshot.
Free for iPhone and iPad (iOS 16.4 or later), with a one-time £4.99 Pro unlock. No accounts, no subscriptions, and the app collects no data.
On your Mac? Point your iPhone camera here to open ViewPortal on the App Store.
Try it right here
Tap a device. Watch it reflow.
A live preview, right on this page — exactly how it behaves in the app.
Tap a device — the page reflows at that exact width, just like in the app. ← → to switch.
Built for developers
Type a URL. Pick a device. Done.
Everything you need to check a layout across every screen — without a laptop in reach.
Dev tools, built in
Tap to inspect any element — size, padding, font, colour — or measure the gap between two. Catch console errors and find layout overflow, right on device.
Side-by-side multi-view
On iPad in landscape, line up phone, tablet and desktop — one URL, three true widths, configured independently.
Capture, annotate & share
Snapshot the preview, mark it up, and send it straight to your team, chat or pull request.
Every preset + your own sizes
iPhone, iPad and 6 Macs — plus any custom width × height. Star the ones you use most.
Localhost, LAN & Tailscale
Point ViewPortal at localhost or a 192.168.x.x dev server — or reach your always-on home Mac from anywhere over Tailscale. Catch breakpoint bugs before you ship.
Private by design
The app has no accounts, no analytics and no tracking. URLs, favourites and preferences stay on your device and are never transmitted.
iPad multi-view
Phone, tablet and desktop — at once.
The hero feature. On iPad in landscape, line up every screen size side by side and watch the same page render at three true widths simultaneously.
- One URL, three viewports. Compare breakpoints in a single glance.
- Configure each pane independently. Different devices, your choice.
- Focus or go fullscreen on any pane for a closer look.
Dev tools
A full dev toolkit. On device.
ViewPortal isn't just a viewer. Inspect any element, watch the console and find layout overflow — the tools you'd reach for on a laptop, right in your pocket.
- Tap to inspect — size, padding, font and colour, or measure the gap between two.
- Console & errors — catch JavaScript issues as the page runs.
- Overflow finder — spot anything spilling past the viewport edge.
How it works
Real viewports, not screenshots.
ViewPortal loads any URL in a real browser engine and forces the page's layout viewport to each device's exact width — so media queries and breakpoints fire correctly. What you see is what your visitors get.
1
Type a URL
Any public site, or your own localhost / LAN dev server.
2
Pick a device
Choose from iPhone, iPad and Mac presets — and rotate to taste.
3
See it for real
The page reflows at the true width, with the exact pixel size shown.
Why I built it
I'm increasingly coding from my phone — prompting AI agents to make changes while I'm on the go.
I kept wanting to check how a desktop-sized layout looked, confirm an agent's change was right, or reproduce a bug report across every device size — without a laptop in reach.
ViewPortal is the tool I wanted: open any URL and see it at true iPhone, iPad and Mac viewports, straight from your iPhone.
Reece · maker of ViewPortal
Pricing
Free to use. Pro once.
Every device preset is free. Pro adds the tools you reach for on a real project, for a single payment. No subscription, no account.
Free
£0
Check any site at real device widths.
- Every iPhone, iPad, iPhone Duo and Mac preset at its true width
- Custom sizes, live pixel readout, device chrome and rotation
- Capture, annotate and share, plus favourites and recents
- Try multi-view free three times
Pro
£4.99 once
For building and debugging, not just looking.
- Multi-view: phone, tablet and desktop side by side
- Your dev server:
localhostand LAN addresses like192.168.1.20:5173 - Dev tools: inspect elements, measure gaps, find overflow, read console errors
- One purchase, no subscription: unlocks on every iPhone and iPad signed in to your Apple Account
Bought ViewPortal before it went free? You already have Pro. It unlocks automatically; if it doesn’t, open Settings and tap Restore Purchases. Prices shown in GBP; the App Store shows your local price.
Questions
Good to know
How much does ViewPortal cost?
ViewPortal is free to download, and you can check any site at every iPhone, iPad and Mac width without paying. ViewPortal Pro is a single £4.99 in-app purchase (US $4.99) that adds multi-view, your own dev servers and the dev tools; try multi-view free three times first. There’s no subscription and no account, and Pro covers every iPhone and iPad signed in to your Apple Account.
I bought ViewPortal before. Do I pay again?
No. Everyone who bought ViewPortal before it went free gets Pro automatically. If Pro doesn’t show as unlocked, open Settings and tap Restore Purchases, or contact support.
Is ViewPortal a web browser?
No — it's a responsive-design testing tool for developers. It uses the same web engine as Safari (WKWebView), but its whole job is to render pages at true device viewport sizes, with device chrome, pixel readouts and multi-view, rather than to browse.
Does it really render at true device sizes?
Yes. It forces the page's layout viewport to each preset's exact width, so the page renders at its real
innerWidth and media queries fire correctly — not a scaled-down screenshot. The live readout shows the precise pixel dimensions you're testing.Can I preview localhost or a LAN dev server?
Yes. Point ViewPortal at
localhost or a 192.168.x.x address to preview work in progress and catch breakpoint bugs before you ship. Local network access is requested only for previewing your own dev servers. Dev-server previews are part of ViewPortal Pro.Does the app collect any data?
No. The app has no accounts, no analytics and no tracking. The web addresses you enter, your favourites and your preferences are stored only on your device and are never transmitted. This website counts visits without cookies, so we can see which pages help people; the privacy policy has the details.
Does it work on both iPhone and iPad?
Yes — it's a universal app for iPhone and iPad. Side-by-side multi-view (phone + tablet + desktop at once) appears on iPad, or on iPhone in landscape, where there's room to show every screen together.
Does it support iPhone Duo?
Yes. Closed, the controls sit in a rail beside the camera so the preview gets the full height; open, previews get big and multi-view sits side by side. There are also iPhone Duo closed and open presets, so you can test your own site at Safari’s real Duo widths from any iPhone or iPad. See iPhone Duo viewport sizes for the numbers.
Is there a responsive design mode on iPhone or iPad?
Not in Safari. Responsive Design Mode is part of Safari on the Mac, and Chrome's device mode is desktop-only too. ViewPortal is the on-device equivalent: pick a preset or type a width and the page reflows at that size. The responsive design mode guide compares the options.
How is it different from Chrome DevTools device mode or Responsively?
Those are desktop tools, and at a desk they do more. ViewPortal runs on the iPhone or iPad you have with you, so you can check a tablet or desktop layout without a laptop. It uses the iOS web engine, so it shows how a page lays out in WebKit at each width; it doesn't emulate Chrome or Firefox.
Need help or want to get in touch?
Happy to help. Email us at support@flavrapps.com or see the support page — ViewPortal has no accounts and keeps everything on your device, so most things are quick to sort. Including your device, your iOS version and what you were doing helps us help you faster. You can also review our privacy policy and terms of use.
Responsive testing, wherever you are.
ViewPortal is free on the App Store for iPhone and iPad, with a one-time Pro unlock when you need it. No accounts, no subscriptions, and the app collects no data.
Download on the App Store