Life & fun · alternatives · 2026

24 alternatives to Duo

Dual-paned web browser for responsive web design.

Duo is a dual-paned web browser designed for developers and QA professionals who need to preview responsive web design layouts. The application displays two browser windows side-by-side, allowing users to view how… Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes. Duo launched in 2013; newer entries below may have overtaken it.

1
Duo▲4
A new way to see Responsive Web Development.
2014 · its alternatives →
2DA
Duo – a next-generation package manager for the front end▲168
2014 · duojs.org · its alternatives →
3
DUO by Mobile Pixels▲114
A second screen for your laptop
2018 · mobilepixels.us · its alternatives →
4
Duo Screen▲68
Providing the most advanced second screen for your laptop.
2014 · its alternatives →
5
Sidekick Browser▲1,050
A productivity browser for becoming focused and unstoppable
2020 · perplexity.ai · its alternatives →
6
Google Duo▲688
One-to-one video calling. Google's FaceTime competitor.
2016 · accounts.google.com · its alternatives →
7
Responsively▲458
Develop responsive web-apps 5x faster
2020 · responsively.app · its alternatives →
8
Tandem 2.0▲537
Unlock serendipity with the most powerful virtual office
2021 · tandem.chat · its alternatives →
9
STUDIO 2.0▲516
Design to live website in one click.
2019 · studio.design · its alternatives →
10
Duo▲412
Personal AI computer for your home. Like JARVIS. 🗣.
2017 · duo.computer · its alternatives →
11
Duet Display▲749
Use your iPad as a second display for your Mac
2014 · duetdisplay.com · its alternatives →
12
COLLABORATE By Sariska▲404
Browse any website together without screen sharing
2023 · kaostogel2d.com · its alternatives →
13
Tandem▲919
A virtual office for remote & distributed teams
2019 · tandem.chat · its alternatives →
14
Duet▲211
A self-hosted alternative to Trello
2016 · its alternatives →
15
My weekend project (split screen surfing)▲71
I wanted to surf the 'net with my girlfriend, so I built this.
2011 · chrome.google.com · its alternatives →
16
Artboard Studio 2.0▲373
Design, collaborate and present all in the browser
2019 · artboard.studio · its alternatives →
17
Polypane (Beta)▲104
Cross-platform responsive design and dev browser
2017 · polypane.app · its alternatives →
18
Allo and Duo▲375
Google’s new smart messaging and video calling apps
2016 · blog.google · its alternatives →
19AS
A self-hosted alternative to Trello, Basecamp, and Freshbooks▲396
2016 · duetapp.com · its alternatives →
20
I saw this mind-blowing experiment, so I made a simple version of it▲403
Two browser windows (acting as socket clients) communicate their: - Screen dimensions - (screen.width, screen.height) - Window dimensions - (window.innerWidth, window.innerHeight) - Window X/Y position - (window.screenX, window.screenY) ...or whichever calculation works best for you. The original work by Bjorn Staal https://twitter.com/_nonfigurativ_/status/172732259457002734 used localStorage, but I found sockets more fun, because if tweaked a bit, this can be shared with friends. Here's a demo of how it works and the codebase:…
2023 · github.com · its alternatives →
21
Relate Preview▲386
Create the web together
2020 · relate.app · its alternatives →
22
Relate 1.0▲343
Create the web together
2021 · relate.app · its alternatives →
23
Stack 2.0▲313
Stack is an internet launchpad for multitaskers
2019 · stackbrowser.com · its alternatives →
24
LT Browser 2.0▲182
Experience 6X faster responsive web development
2023 · testmuai.com · its alternatives →

Also compare

Ranked by how close each launch is in meaning, then by votes. Prices were read from each product’s own site when checked and can change. Refine with your own description →