Post
Change your code or assets and see the results instantly without restarting the entire game.
Hot reloading is the ability to modify code, shaders, textures, scripts, or other assets in a running game and see the changes reflected immediately without restarting. It transforms the iteration loop from 'make a change, recompile, relaunch, navigate back to where you were testing' into 'make a change, see it live.' Unreal Engine's Live Coding, Unity's hot reload for C# scripts, and Godot's scene reloading all implement versions of this. For scripting languages like Lua, hot reloading is often trivial. For compiled languages, it requires sophisticated memory management to swap out functions while keeping game state intact.
Example
Naughty Dog built a custom hot-reload system for The Last of Us Part II that let designers tweak enemy AI behavior, animation timing, and encounter scripting in real-time during playtesting sessions, dramatically accelerating iteration on the game's intense combat encounters.
Why it matters
Development speed is directly tied to iteration speed. If every small tweak requires a 30-second recompile and relaunch, developers make fewer experiments and settle for 'good enough' sooner. Hot reloading turns game development from a slow feedback loop into a creative conversation.
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