Index - Erlang/OTP

fact(0) -> 1; %% Pattern matching for control-flow fact(N) -> N * fact(N-1). %% Recursion to create loops > example:fact(10). %% Interactive shell for fast iterations 3628800 > [{I, example:fact(I)} || I <- lists:seq(1,10)]. [{1, 1}, {2, 2}, {3, 6}, {4, 24}, {5, 120}, {6, 720}, {7, 5040}, {8, 40320}, {9, 362880}, {10, 3628800}]

> Fruits = ["banana","monkey","jungle"]. %% Immutable variables ["banana","monkey","jungle"] > lists:map(fun string:uppercase/1, Fruits). %% Map values using stdlib functions ["BANANA","MONKEY","JUNGLE"] %% Fold over lists using custom functions > lists:foldl(fun(Str, Cnt) -> string:length(Str) + Cnt end, 0, Fruits). 18

> Parent = self(). %% Get own process id <0.376.0> > Child = spawn(fun() -> receive go -> Parent ! lists:seq(1,100) end end). <0.930.0> > Child ! go. %% Send message to child go > receive Reply -> Reply end. %% Receive response from child [1,2,3,4,5,6,7,8,9,10,11|...]

-spec even(list(integer())) -> list(integer()). even(Numbers) -> mapreduce(Numbers, fun(Number) -> Number rem 2 == 0 end). mapreduce(Numbers, Function) -> Parent = self(), [spawn(fun() -> Parent ! {Number, Function(Number)} end) || Number <- Numbers], lists:flatten( [receive {Number, true} -> Number; _ -> [] end || Number <- Numbers]).

What is Erlang?

Erlang is a programming language used to build massively scalable soft real-time systems with requirements on high availability. Some of its uses are in telecoms, banking, e-commerce, computer telephony and instant messaging. Erlang's runtime system has built-in support for concurrency, distribution and fault tolerance.

Erlang Quickstart

What is OTP?

OTP is set of Erlang libraries and design principles providing middle-ware to develop these systems. It includes its own distributed database, applications to interface towards other languages, debugging and release handling tools.

Getting Started with OTP

News

Erlang/OTP 29.1 Release September 16, 2026 by Henrik Nord: Erlang/OTP 29.1 is the first maintenance patch package for OTP 29, with mostly bug fixes.
Björn on BEAM on the BEAM There, Done That Podcast June 26, 2026 by Björn Gustavsson: Björn on BEAM on the BEAM There, Done That Podcast
Native Records on the Podcast BEAM There, Done That May 28, 2026 by Björn Gustavsson: Native Records on the Podcast BEAM There, Done That

Practical functional programming
for a parallel world

What is Erlang?

What is OTP?

News

Erlang/OTP 29.1 Release

Björn on BEAM on the BEAM There, Done That Podcast

Native Records on the Podcast BEAM There, Done That

Participate

Practical functional programming for a parallel world

What is Erlang?

What is OTP?

News

Erlang/OTP 29.1 Release

Björn on BEAM on the BEAM There, Done That Podcast

Native Records on the Podcast BEAM There, Done That

Participate

Practical functional programming
for a parallel world