Microsoft’s C# has won the Tiobe Index Programming Language of the Year designation for the second time in three years, with the largest year-over-year increase in ranking in the company’s programming language popularity index. Meanwhile, another Microsoft language, TypeScript, may crack the index’s top 20 this year, according to Tiobe CEO Paul Jansen.

Tiobe announced C# as its language of the year for 2025 on January 4. C# rose 2.94 percentage points year over year, with a rating of 7.39% and ranking of fifth this month. C#’s winning the award had been expected; the language was also Tiobe’s language of the year for 2023. “From a language design perspective, C# has often been an early adopter of new trends among mainstream languages,” wrote Paul Jansen, CEO of the software quality services vendor, in a bulletin accompanying the January 2026 index. “At the same time, it successfully made two major paradigm shifts: from Windows-only to cross-platform, and from Microsoft-owned to open source. C# has consistently evolved at the right moment.” Jansen added that he had expected C# to prevail against Java for dominance in the business software market, but the contest at this point remains undecided. “It is an open question whether Java—with its verbose, boilerplate-heavy style and Oracle ownership—can continue to keep C# at bay, said Jansen. Java was rated third in this month’s index behind Python and C, with an 8.71% rating.

Jansen concluded his bulletin with a prediction about TypeScript, Microsoft’s JavaScript with syntax for types. “I have a long history of making incorrect predictions, but I suspect that TypeScript will finally break into the top 20,” Jansen said. The language is currently ranked 32nd. “The reason why I think TypeScript will grow is because I see that a lot of front-end software (user interfaces) are written in TypeScript instead of JavaScript nowadays,” Jansen said. “The advantage of TypeScript over JavaScript is that it is type-safe.” If developers use TypeScript in the right way, it is much harder to shoot yourself in the foot, Jansen said. “Adopting TypeScript is without any risks because TypeScript compiles to JavaScript. Hence, you can always go back to JavaScript if you don’t like TypeScript.”

Tiobe’s monthly index ratings are based on a formula that assesses the number of skilled engineers worldwide, courses, and third-party vendors pertinent to a language. Popular websites such as Google, Amazon, Wikipedia, Bing, and more than 20 others are used to calculate the ratings. Elsewhere in the index for January 2026, Jansen said Go appears to have permanently lost its place in the top 10 last year. The same seems true for Ruby, which fell out of the top 20 and is unlikely to return anytime soon, according to Jansen. But Perl made a surprising comeback, rising from position number 32 in January 2025 to number 11 by the end of the year. Another resurgent language is R, which returned to the top 10 in 2025, driven largely by continued growth in data science and statistical computing, Jansen said. The C language, now ranked second, and C++, now in fourth place, swapped positions in the index over the past year.

The Tiobe index top 10 for January 2026:

1. Python, 22.61%
2. C, 10.99%
3. Java, 8.71%
4. C++, 8.67%
5. C#, 7.39%
6. JavaScript, 3.03%
7. Visual Basic, 2.41%
8. SQL, 2.27%
9. Delphi/Object Pascal, 1.98%
10. R, 1.82%

The alternative Pypl Popularity of Programming Language Index assesses language popularity based on a formula that analyzes how often language tutorials are searched on in Google.

The Pypl index top 10 for January 2026:

1. Python, 24.61%
2. C/C++, 14.13%
3. Objective-C, 13.35%
4. Java, 10.45%
5. R, 6.18%
6. JavaScript, 4.68%
7. Swift, 3.68%
8. PHP, 2.95%
9. C#, 2.79%
10. Ada, 2.71%