Introducing BrowserSwarm – Spend less time testing your next JavaScript project

September 26th, 2013

Today, along with appendTo and Sauce Labs, we are releasing BrowserSwarm – an open source tool that helps Web developers automate testing of their JavaScript frameworks and libraries across devices and browsers. Quality frameworks are the foundation for the modern Web, but framework developers often do not have the resources to test across browsers. BrowserSwarm helps developers build great, interoperable frameworks. The project complements modern.IE, which provides a set of free tools and resources to help developers build Web sites for all modern browsers.

You can set-up your BrowserSwarm account in minutes here.

BrowserSwarm: Fast, Actionable Test Results

BrowserSwarm connects directly to your team’s code repository on GitHub and uses Sauce Labs’ cloud to automatically run Unit Tests using QUnit. A simple report separates which test cases passed and failed so you can quickly see what needs to be fixed.

BrowserSwarm provides test results using top frameworks and libraries such as prototype.js and Modernizr. You receive an overall pass rate across browsers and devices, along with individual test pass rates for top browsers.

Here is an example from a recent Job for underscore.js:

Sample BrowserSwarm test result page for underscore.js

Sample BrowserSwarm test result page for underscore.js

Individual job reports display only the test cases that fail, so you can quickly focus on what needs to be fixed. You can always view the full test output if you are familiar with running Unit Tests in QUnit.

Sample BrowserSwarm detailed error report

Sample BrowserSwarm detailed error report

Community Contributions Make BrowserSwarm Testing Even Better

The testing power of BrowserSwarm grows as the community contributes to the open source project. Here are a few ways that you can help grow BrowserSwarm:

  • More projects – Add yours to BrowserSwarm here.
  • More test cases – Contribute new Unit Test Frameworks or Test Cases to run.
  • More places you store your code – We have connected BrowserSwarm to GitHub, but you can connect it to your own repository.

Please share your feedback and ideas on how we might improve BrowserSwarm.

Our Commitment to the Web – Interoperability, Tools, and Resources

BrowserSwarm is an open source partnership – continuing our long history of working with the community to make the Web better. We have over 90 Microsoft people involved in 63 W3C working groups, and we have submitted thousands of test cases and hundreds of core reference docs to With the new F12 Developer Tools in IE11, free site scanning tool on, and free virtual machines, we continue to help developers build a new class of modern Web experiences.

Sandeep Singhal

Group Program Manager, Internet Explorer

Questions? Suggestions? Reach out to @IEDevChat.