Main image of article JavaScript, SQL Top Skills That Employers Test For

If you apply for a job as a developer, chances are good that the company will subject you to a coding test of some sort. If you’re lucky, such coding tests mimic how you actually work; for example, you might be asked to complete a small task online, with access to Google and everything else you need. However, some employers are still locked into the idea of using whiteboards to test candidates on esoteric programming points.

Because there are so many different approaches to testing, it’s helpful when a company surveys the industry to find out what companies are actually testing for. Devskiller, a platform for screening and technical interviews, did just that; and it found that JavaScript was the most tested-for language on its platform (cited by 40 percent of respondents), followed by SQL (33 percent), Java (31 percent), HTML/CSS (20 percent), and .NET/C# (2 percent). (No, that doesn’t add up to 100 percent, because respondents could select multiple options.)

“This just goes to show how important the front-end has become to software development,” read the note accompanying Devskiller’s data, which was drawn from 213,782 coding tests in 143 countries. “It just goes to show that while large back-end teams are still important, the overwhelming need for developers to work on web apps has eclipsed the need for them to create large back-end systems.”

Companies are looking for JavaScript developers, in other words; they also need SQL developers who can successfully work with databases: “What these findings show is that when it comes to full-stack development, the combination of IT skills required are increasingly JavaScript on the front-end along with SQL to [complement] a server-side tech stack.”

For anyone who tracks the relative popularity of programming languages, the dominance of JavaScript shouldn’t come as too much of a shock. The language regularly dominates lists that attempt to rank languages, such as the TIOBE Index and RedMonk. According to Stack Overflow’s annual Developer Survey (which is quite extensive), JavaScript remains the most popular programming language (with 67.8 percent of respondents favoring it), well ahead of HTML/CSS (63.5 percent), SQL (54.4 percent), and Python (41.7 percent). 

If you’re interested in learning JavaScript, check out, which lists a variety of courses and tutorials for various languages. Mozilla’s site also has a very nice rundown of the language’s basics, including a crash course in comments, operators, variables, and other elements. offers an extensive walkthrough of fundamentals, including the ever-popular “Hello, world!” For those willing to self-learn, the free resources are definitely out there.