Due to technical and personal reasons, I'm not able to work on this project anymore. It is now archived and it won't get any further updates.

Thank you everyone for using slashB and for your support and comprehension.

A browser for

Spend half the time designing and developing responsive websites by testing them on multiple screens at once

macOS, Windows, and Linux


Never resize your browser again

Emulate real devices by using their screen sizes, or use responsive CSS breakpoints.

Organize devices

Reorder, clone, delete, hide, and create devices with custom dimensions, user agent, etc.

All your actions are in sync

When interacting with one viewport, slashB will mirror all your actions (click, focus, scroll, forms input) on the others.

Built-in live reloading

If your local setup supports Hot Reloading, you can instantly see all the changes you make across all the devices.

Powerful developer tools

slashB includes Chrome/Chromium's devtools, with support for devtools extensions like React, Vue, Angular, Svelte and more.

Screenshots made easy

Take a screenshot of the visible viewport, or the entire page.

Light and dark modes

Switch between light and dark theme to match your preferences.

... And more!

Customizable device presets

Search in pages

Easily clear cache, cookies and local storage

Quickly rotate devices

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30-day trial


  • Try slashB for free to make sure it fits your needs
  • No feature restrictions
  • No credit card needed



  • One-time payment
  • Indefinite access to all updates to slashB 1.x
Single-user license
Max 3 devices
Price might change depending on your local currency
We are not able to offer refunds at the moment, sorry
More info in the FAQs page
Sold and fulfilled by Paddle, an authorized reseller