Why C# Overtook Java in 2023: Insights from the TIOBE Index

The 2023 TIOBE Index officially announced C# as the Programming Language of the Year, marking the first time in 23 years that C# reached the top spot.

C# showed a 1.43% increase in popularity, outpacing competitors like Scratch (0.83%) and Fortran (0.64%). The index also notes that C# is gradually eroding Java's market share, especially in web back‑ends and game development.

Java’s parent company Oracle switched to a subscription model based on total employee count in early 2023, prompting many companies to abandon Java projects due to the steep £72 million annual fee, which contributed to a 4.34% loss in Java’s market share from January 2023 to January 2024.

C# remains free and open‑source since 2014, benefits from deep integration with Microsoft tools, and enjoys strong community support on GitHub.

Microsoft’s official language, tightly coupled with Visual Studio and .NET, offers high interoperability on Windows and other Microsoft platforms.

79% of C# developers use Windows, and 99% of .NET projects are written in C# (JetBrains 2023 Developer Ecosystem report).

Static typing and robust compile‑time checks catch many errors early.

C# 12 introduces modern features such as primary constructors, collection expressions, and inline arrays.

Visual Studio provides a powerful IDE with extensive debugging and automation tools.

.NET Core and .NET 8 enhance cross‑platform capabilities, allowing development on Windows, Linux, and macOS.

C# is widely used for desktop, mobile, IoT, web, cloud‑native, and Unity‑based game development.

Other languages also saw notable movements: Fortran re‑entered the Top 20, reflecting its continued use in scientific and engineering simulations, while Kotlin climbed to rank 17 after years of Android adoption. COBOL surprisingly appeared in the Top 20 due to high demand for legacy banking and unemployment‑benefit systems in the United States, prompting IBM to launch an AI‑driven code‑generation assistant to translate COBOL to Java.

Looking ahead to 2024, TIOBE CEO Paul Jansen predicts that Dart (with Flutter) and TypeScript may break into the Top 20, while Julia needs a more mature ecosystem to regain its position.

The TIOBE Index measures programming language popularity based on the number of skilled engineers, courses, and third‑party vendors, but it does not claim to rank languages by quality or code volume.

Historical rankings from 1988 to 2024 show long‑term trends, and a “language celebrity” list highlights the most influential languages over the past two decades.