Recently in a meetup organized by FSharp Paris, I spoke with a beginner in FSharp trying to implement Fibonacci to learn language bases.

This algorithm is often taken as an example in the tutorial of beginners in FSharp. This is because it is very simple and known by all developers. It is very common to want to implement it in recursive. However, this gives a false picture of the FSharp’s performance (this was the case). So I had fun writing this Gist containing 3 implementations (recursive / iterative / tail recursive) with their benchmarks.