Cross-browser and real device testing is a service that keeps real phones, tablets and browser versions in a data centre, and rents them to software teams over the internet. A team's automated tests can run on hundreds of these devices at the same time. A tester can also open any single device in a browser window and use it by hand. The service is often called a cloud test grid or a device cloud.
Why rent phones? An app must work on every phone its customers own. In India, that means dozens of Android models from many brands, many of them low-cost phones with little memory, plus several iPhone models. Each runs a different version of Android or iOS, and each brand changes Android in its own way. A website must also work in Chrome, Safari, Firefox and Edge, in several versions of each. Few teams can buy, charge and update hundreds of devices. The grid company does this once, and rents the devices to thousands of teams.
Real devices matter because a simulator, a program that imitates a phone on a laptop, does not show everything. It does not have the real phone's camera, its battery saving, its notifications or its slower chip.
Say a small finance bank in Kolkata is about to release a new version of its mobile banking app. It has 400 automated tests, from login to a fund transfer. The CI/CD pipeline sends them to the grid, with a list of 60 devices. These are the phone models that most of the bank's customers use, according to the app's own data. The grid runs the tests on all 60 devices in parallel, and finishes in 25 minutes. By hand, the same work would take a team about two days. The report shows that on one older Android model, the "Transfer" button is hidden behind the keyboard. Each failed test comes with a video of the screen and the device's log, a line-by-line record of what the phone did. A tester then opens that model by hand, from her laptop, and confirms the problem.
The tests themselves are written in test automation tools. The grid decides how to run a large set of them through test orchestration. It can measure speed as well as correctness, through mobile app performance testing. Grid companies now also offer AI testing agents that write the tests that run on their devices.
Several of the largest companies in this business were founded in India, in Mumbai and Noida. Their customers are software teams across the world.