What Programming Languages Does Jagex Use?

A company built on one language, then forced to diversify

Jagex is often described as “a RuneScape company,” but the more accurate view is that it is a long running live service studio that has had to evolve its technology stack repeatedly as the internet, hardware, security expectations, and player scale changed, which means the answer is not one language but a set of languages that each exist for a specific reason: a stable core that can run forever, client technology that can keep modernizing, and a surrounding ecosystem of web systems that handle accounts, publishing, and delivery.

 

Java is still the center of gravity for RuneScape and OSRS

Historically, RuneScape’s identity is tied closely to Java because the game’s long life began in a world where cross platform delivery mattered more than raw graphics performance, and even today Old School RuneScape still exposes a Java based client configuration flow, which reflects how deeply Java is embedded into the “OSRS era” tooling and distribution model even as launchers and platforms evolve.

 

The NXT era brought C++ into the client conversation

As RuneScape pushed toward a more modern client experience, Jagex publicly discussed moving away from the limitations of Java on the client side, including the creation of a newer C++ client, which fits a common MMO pattern where the gameplay world and server logic can remain stable while the rendering and client performance layer gets rewritten to better match modern graphics expectations and hardware acceleration.

 

Web and platform engineering uses modern JavaScript tooling

Outside the game itself, Jagex has also talked about its web technology direction and the tools used to deliver web experiences, explicitly describing work with TypeScript and Node.js (alongside their content platform choices), which is the same class of stack you would expect from a studio that needs fast iteration, reusable UI components, and reliable content delivery across marketing pages, account flows, and live product surfaces. 

 

Tooling, libraries, and scripting exist around the core loop

Even when a studio’s headline languages are “Java” and “C++,” real production is always wider than that, because content pipelines, build automation, internal editors, data validation, and operations tooling often involve additional languages and scripting, and job descriptions for game development roles commonly reference maintaining large Java code libraries while also working with scripting languages and engine technologies, which is a practical reminder that studios rarely run purely on one language once they have multiple games, multiple deployment targets, and multiple live workflows. 

 

What this means for RSPS developers trying to learn from Jagex

The most important takeaway is not chasing a “secret language,” because there is no single magic choice, it is understanding why Jagex ended up with a split world where long lived, stability focused layers stay conservative while performance and delivery layers modernize, and if you map that thinking onto RSPS development you end up with a healthier mindset: pick a core you can maintain for years, accept that clients and web systems evolve faster than game rules, and build your tooling so you can change parts of the stack without risking the entire world every time you ship.