Karma vs Rainforest QA: What are the differences?

Karma: Spectacular Test Runner for JavaScript. Karma is not a testing framework, nor an assertion library. Karma just launches a HTTP server, and generates the test runner HTML file you probably already know from your favourite testing framework. So for testing purposes you can use pretty much anything you like; Rainforest QA: Front-end QA as a service. Rainforest gives you the reliability of a QA team and the speed of automation, without the hassle of managing a team or the pain of writing automated tests.

Karma and Rainforest QA can be primarily classified as "Browser Testing" tools.

Some of the features offered by Karma are:

• Test on Real Devices
• Remote Control
• Testing Framework Agnostic

On the other hand, Rainforest QA provides the following key features:

• Infinitely Scalable, On-Demand QA Team
• Cross Browser Testing
• Regression, Functional, and Exploratory Testing

"Test Runner" is the primary reason why developers consider Karma over the competitors, whereas "Cross-browser testing" was stated as the key factor in picking Rainforest QA.

Karma is an open source tool with 10.7K GitHub stars and 1.61K GitHub forks. Here's a link to Karma's open source repository on GitHub.