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Mike T
27 posts
What languages do Riot use for League of Legends
I was curious when this question came up in the stream and googled it.
This thread on the LoL forums by a "Core Team" person seems to answer this:

Relevant excerpt:
Lima Beans - Core Engineer:
we use at least the following languages here
C++ (the core game is written in this)
Lua (core game)
C# (game tools)
ActionScript (game hud and pvp.net)
Java (platform servers)
Erlang (platform servers)
Php/sql (web team / platform)
Casey Muratori
801 posts / 1 project
Casey Muratori is a programmer at Molly Rocket on the game 1935 and is the host of the educational programming series Handmade Hero.
What languages do Riot use for League of Legends
That looks pretty typical, with the exception perhaps of Erlang (I'm not sure I've heard of that being used in platform servers, but I don't deal much with people who do that sort of thing).

Like I was saying on the stream, the idea here is to minimize the risk that there will be problems with real-time performance, so C/C++ tends to be the safe choice for anything that is time-critical. For things that are not time-critical, such as level editors and such, C# is not uncommon.

Just my personal experience hearing what people tend to do.

- Casey