The TIOBE index for September 2025 brings some notable surprises and at the same time confirms some trends already observed in recent months. At the top of programming languages, Python consolidates its position as the absolute leader, while older languages, considered almost "disappeared" from the forefront, make a spectacular comeback.
Python – an undisputed leader
Python remains in first place, with a share of 25.98%, up by over 5.8% compared to last year. This advance is not only a confirmation of its popularity but also proof that the Python ecosystem continues to expand. Fields such as artificial intelligence, data analysis, machine learning, and automation make it the preferred choice for both beginners and professionals. It is clear that Python has become a de facto standard in many areas of software development.
The fight for places 2–4: C++, C, and Java
In second place is C++, with a share of 8.80%, although down by almost 2% compared to last year. Very close behind is C, with 8.65%, slightly increasing, while Java drops to fourth place, with 8.35%, losing over 1%. These fluctuations show relative stability in the "classic" languages area but also a downward trend for Java, which seems to be gradually eclipsed by more modern and efficient alternatives.
C# and JavaScript maintain their positions
C# holds fifth place, with 6.38%, a modest but steady increase, demonstrating that the .NET ecosystem remains solid. JavaScript, although still essential for web development, stands at 3.22%, declining. The popularity of modern frameworks and the emergence of alternatives for front-end may explain this downward trend.
The surprising comeback of Perl and Ada
The biggest surprise of this ranking is the spectacular return of the Perl language, which jumped from 27th place directly into the top 10, reaching 2.03%. This unexpected rise is largely due to enterprise and infrastructure projects that still rely on Perl, as well as the community that keeps the language relevant in certain niches.
Another winner of the month is Ada, which climbs to 14th place, with a share of 1.27%, up by +0.56%. Although traditionally associated with aviation and critical systems, its growth shows renewed interest in robust and secure solutions.
Other important changes
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Delphi/Object Pascal re-enters the top 10, at 9th place.
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R rises slightly, remaining relevant in statistics and data science.
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Rust and MATLAB lose ground, falling out of the top 15.
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Kotlin, promoted by Google as the main language for Android, stagnates at 0.95%, raising questions about its future.
Conclusion
The TIOBE ranking for September 2025 shows a diverse landscape: on one hand, Python dominates without rival in many modern fields; on the other hand, older languages like Perl and Ada demonstrate that mature technologies do not completely disappear but can come back into focus when the context favors them. For developers, this ranking is a good opportunity to evaluate where it is worth investing time and energy, whether it is about strengthening knowledge in Python or exploring niche languages with surprising potential.
