How Pinterest uses Elixir
Pinterest used Elixir for high-volume notification delivery and API rate limiting. It also built Guardian, a real-time query and rules engine for detecting spam.
Guardian combines user events and spam signals into a dataset that analysts can query and use to create rules. Elixir coordinates concurrent work, with lower-level performance-sensitive operations implemented in C. These are documented implementations from 2015-2021, not a claim about the entire current Pinterest stack.