44% of developers most often use two programming languages in their work.
But «entering IT» is also possible with one language — 37% of developers who started working in 2023 use only one language in their work.
About it says in the DOU statistics.
TypeScript and JavaScript are most often used together. C#/.NET, Java, PHP, Python, Ruby, Salesforce are often combined with TypeScript and JavaScript. Backend developers are more likely than other developers to use only one language in their work.
However, the more experienced a developer is, the more languages they use. Only 21% of SEs with 10 years of experience can get by with one language, while 43% write in three or more languages.
Full Stack and Mobile developers have to learn the largest number of languages. 85% of full stackers use 2-3 programming languages at the beginning of their career.
Mobile developers can start working with knowledge of one language: 59% of those who have been working in this field for less than a year write in only one. However, the need to learn other languages quickly arises. Among developers with up to two years of experience, 44% already use one language, and —34% with up to five years of experience. Among mobile developers who have been in the industry for more than nine years, more than half use three or more languages, the highest rate among all specializations.
Almost a third of Back-end specialists use only one programming language in their work. Even among developers with 10 years of experience or more, 24% use only one language, the highest rate among all specializations.
Front-end developers, both experienced professionals and beginners, mostly need two programming languages.
Backenders can get by with one language more often than others
10% of backenders use only Java, 8% use only C#/.NET, and 5% use only Python. They most often choose JavaScript as a second language: 7% combine it with PHP, 4% each with Java, C#/.NET, and TypeScript.
The combination of Python and JavaScript is gaining momentum: 12% of newcomers who entered backend development less than a year ago write in these languages, compared to 3% of all backenders. The combination of JavaScript and TypeScript is also becoming more popular — it is used by 9% of newcomers versus 4% of all backend developers.
The majority of front-end developers use JavaScript and TypeScript — 76% write only in these two languages or one of them. About half of front-end developers use both JavaScript and TypeScript. 14% use JavaScript only, 8% use TypeScript only. Some front-end developers add PHP to these languages.
Full stackers also like JavaScript and TypeScript (though not as much as front-enders). 16% of Full Stack developers use only these two languages, another 7% use only JavaScript, and 2% use only TypeScript. Another common variant is a combination of these languages with C#/.NET: 11% of Full Stack developers choose these three languages, 6% — C#/.NET and JavaScript, 5% — C#/.NET and TypeScript. Less often they are combined with PHP: 8% write in PHP and JavaScript, 5% in PHP, JavaScript, and TypeScript.
Like backenders, full stack developers are starting to use a combination of JavaScript and TypeScript more often (26% of newcomers vs. 16% of all full stack developers) and Python and JavaScript (5% of newcomers vs. 2% of all full stack developers).
The most popular combination of languages among mobile development specialists is Kotlin and Java (17% code only in these two languages), and another 7% use Kotlin alone. Only Swift is chosen by 12% of mobile developers, and another 7% — Swift together with C and Objective-C (mostly developers with 10 years of experience). 6% prefer only C#/.NET, and 5% — only Dart.
The popularity of Kotlin and Dart in mobile development is growing. 24% of Mobile developers who have been working for less than a year write only in Kotlin (vs. 7% of all Mobile developers). 10% of newcomers work only with Dart vs. 5% of all Mobile developers in general.
C#/.NET, Java, Python, Swift, and Dart are used more often than other languages on their own and less often combined with other programming languages.
TypeScript and JavaScript are most often used together. Only a small part of developers can use only JavaScript (28% of those for whom it is the main language) or only TypeScript (16%).
C#/.NET, Java, PHP, Python, Ruby, Salesforce are often combined with TypeScript and JavaScript.
C and C++ are often used together with Python and C#/.NET.
Go is combined with Python, and somewhat less often with JavaScript. Python is often used by those whose main programming language is Rust.
Almost half of the developers whose primary programming language is Kotlin choose Java. Swift users tend to work only with it or combine it with C and Objective-C. Dart is used alone or combined with Kotlin, Swift, and Java.