Two is a beautifully designed app for testing your responsive designs. View the mobile view and desktop view side by side to quickly diagnose differences and issues.

Featuring resizable views for mobile and desktop, plus handy responsive breakpoints built in, Two gets out of your way and let's you do what you do best.

What's New

Version 1.2

Two isn't dead yet! This is a quick point release to introduce the ability to have Two be a target to send your HTML files to via the "send to" or "open with" menus. More great things to come!

Ratings and Reviews

Very Important App


This app is actually very important and needs to be brought up-to-date with some functionality.

The table of breakpoints need to be updated to various browsers and sizes with their accompanying names. Likewise agents. This list needs to be perpetually updated or community.

The functionality of Safari's "Responsive Design Mode" can be used to also refine the experience, but to make it overall much more robust and comprehensive.

Indispensible for RWD testing


I’ve been using Two since it was in Beta and I’ve been seriously impressed with how well it works and how it’s gotten better with each release.

I can’t imagine not having it in my arsenal now. It’s well worth the price.

Invaluable for Responsive Web Design (RWD)


Updated review: I don’t know enough about coding to know how this works, but Two is not showing up as a "web browser” so when a web building app like RapidWeaver gives a choice to open a site in a browser, Two is not showing up in the list—so Two becomes almost unusable. Whatever missing code is absent to enable Two to be seen as a web browser needs to be put back in. Or added. Or whatever is needed.

When Two works, it’s exceptional and deserves at least 5 stars. Right now, Two gets a 2.

This is a fabulous resource to have on hand when checking your work live. It’s also great for doing a live demo with prospective clients for demonstrating RWD. I’d give it 10 stars if I could. I’m surprised it’s not 19.99 instead of just 1.99.


Christopher Davis
3.3 MB
Developer Tools
Age Rating
You must be at least 17 years old to download this app.
Unrestricted Web Access
© Chris J. Davis


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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