// the find
devonestes/fast-elixir
:dash: Writing Fast Elixir :heart_eyes: -- Collect Common Elixir idioms.
fast-elixir is a benchmark-backed catalog of Elixir idioms where more than one semantically equivalent way to write something exists, showing which is actually faster using benchee. It's for intermediate-to-advanced Elixir developers who want real numbers instead of folklore about things like ets vs GenServer or list concatenation vs cons.
Every idiom ships with actual benchee output (ips, deviation, memory usage) rather than just an assertion, and the runnable .exs source for each example is linked so you can reproduce or extend it. The selection covers genuinely non-obvious BEAM tradeoffs — ets/persistent_term/GenServer state access, IO lists vs string interpolation, `++` vs cons+flatten — that documentation rarely quantifies. It's inspired by and structured like fast-ruby, so the format is proven and easy to skim.
Last push was November 2023 and the benchmarks themselves are pinned to Elixir 1.11-rc / OTP 23, so several comparisons may no longer hold on current BEAM versions with newer JIT and binary optimizations. There's no CI that re-runs the benchmarks, so a reader has no way to know if a given result is still accurate versus quietly stale. It's a static reference, not a library, so there's nothing to actually adopt — the real risk is treating a three-year-old micro-benchmark as current truth for a production decision.