The December TIOBE index shows some interesting shifts in the popularity of programming languages. Particularly striking is the rise of C, which climbs from fourth to second place, while R also returns to the top 10 after a long absence.
The TIOBE index provides a monthly snapshot of the popularity of programming languages and is often used to identify broader trends in software development. The ranking is explicitly not a measure of quality, but provides insight into which languages are visibly gaining or losing ground. It is not an absolute measure of popularity, but measures search queries. The index faces some significant criticism, which is why it is a good thing we also have Stack Overflow’s Developer Survey as well as GitHub data to compare it to.
C has risen to a ‘market’ (read: search) share of 10.11 percent, a clear increase compared to last year. The programming language remains as relevant as ever in areas where performance, hardware proximity, and control are key, such as embedded systems, operating systems, and infrastructure software. The renewed focus on efficiency, security, and energy consumption seems to be reigniting the popularity of C, partly due to the growth of IoT and industrial automation.
In addition to C, R is one of the most notable climbers. The language has climbed from 16th to 10th place, returning to the top 10 of the TIOBE index. R is specifically designed for statistical calculations, data analysis, and visualization. It also has an extensive ecosystem of packages for machine learning, bioinformatics, econometrics, and more.
R very effective for rapid analysis
Although R is less suitable for large-scale production systems and is sometimes seen as a niche language by traditional software developers, it remains highly effective for rapid analysis. It is also useful for experimental research and working with complex data sets. R therefore retains a firm place, particularly in academic environments and data-driven organizations. This is in addition to broader languages such as Python.
It is striking that Rust, a language often mentioned as a modern alternative to C and C++, is only growing moderately in the TIOBE index. Despite a lot of attention to security and memory management, adoption remains moderate according to this measurement.
Little has changed at the top of the index. Python remains by far the most popular programming language. It is also striking that C# is gaining ground again and, according to TIOBE, is currently the strongest contender for the title of Programming Language of the Year 2025. The organization will officially announce this next month.