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The Move to Python 3 Begins!
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- DeepHorus
CCP Games has announced the beginning of a monumental migration: EVE Online, the iconic space-faring MMO, is moving its codebase from legacy Stackless Python to Python 3. This development was revealed in a post dated August 25, 2026, marking the start of a long overdue update for the game's backend technology.
For over two decades, EVE Online has served as a real-world example of running a complex, large-scale MMO on Python. The game has been built on Stackless Python since its launch in 2003, with the last major upgrade being a move to Stackless Python 2.7 back in 2010—over sixteen years ago.
The migration project is massive in scope, targeting approximately 2.4 million lines of code. The initial phase will employ the automated futurize script to handle the conversion, which will then be followed by a meticulous manual review of around 20,000 specific instances where Python 2 and 3 behaviors diverge, such as the result of integer division.
This upgrade is crucial for the game's long-term health, ensuring access to modern libraries, security updates, and performance improvements inherent to the Python 3 ecosystem. However, the announcement did not detail the plan for replacing the custom Stackless Python runtime, which provides lightweight concurrency essential for the game's architecture.
Speculation within the community suggests CCP may leverage experience from their newer title, EVE Frontier. At a recent conference, the studio presented on "Scheduling in Carbon," describing how they replaced Stackless in the Carbon engine using their now open-source scheduler library.
The project underscores the technical challenges of maintaining living software at a planetary scale. While the full timeline remains unclear, this move is a foundational step toward ensuring EVE Online's infrastructure remains viable for its next decade of gameplay.
