# How Discord Scaled Elixir to 5,000,000 Concurrent Users  ## Metadata - Author: [[Stanislav Vishnevskiy]] - Full Title: How Discord Scaled Elixir to 5,000,000 Concurrent Users - Category: #articles - Source: medium - Last Highlighted: 2024-10-30 10:08:51.642220+00:00 - URL: https://medium.com/p/f9b8e1e7c29b ## Highlights - Sending messages between Erlang processes was not as cheap as we expected, and the reduction cost — Erlang unit of work used for process scheduling — was also quite high. - Erlang processes are effectively single threaded, and the only way to parallelize the work is to shard them. - if Erlang sees a function that always returns the same constant data, it puts that data into a read-only shared heap that processes can access without copying the data.