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Netwire is a functional reactive programming library that provides both an applicative and an arrow interface. It allows you to express time-varying values with a rich event system.


Here is a list of some of the features of Netwire:

  • applicative interface (or optionally an arrow interface),
  • signal intervals,
  • dynamic switching,
  • rich set of predefined functionality,
  • signal analysis (average, interpolation, peak, etc.),
  • effectful reactive systems.


Netwire's FRP framework is intended to be used for continuous applications. It replaces the traditional big main loop with its global state and event callbacks/branching by a completely declarative model. The following types of applications can benefit from using Netwire:

  • artificial intelligence and bots,
  • canvas-based graphics and animations,
  • continuous signal synthesis (audio waves, etc.),
  • games and game servers,
  • scene-based user interfaces (like OpenGL and vty),
  • simulations.

If you can sensibly break your application down into frames, then Netwire is for you. For other kinds of reactive applications like widget-based UIs you may want to look into reactive-banana instead.

Get started

The documentation is contained within the package itself, but you can also read it online:

Other reading


Model and correctness

Netwire's underlying abstraction is more powerful than the original formulation of time-varying values. It allows you to implement general component systems with local state.

Starting with Netwire 5 there are two module trees Control.Wire and FRP.Netwire. The latter exports a subset of Netwire that closely follows the original model and provides a set of predefined FRP wires.

Signal intervals are an extension of the original model and an integral part of Netwire: A behavior is a partial function of time with the limitation that both the defined and undefined intervals must have a non-zero length. This extension makes it much easier to express switching and multicasting systems.


This project started in 2011 as a replacement for Yampa to provide both a nicer interface and better integration into existing frameworks. Its original purpose was to power game servers and intelligent network bots. That's the origin of the name Netwire.

However, before its first release signal intervals were added (originally under the term signal inhibition). Netwire became a completely new abstraction, so it lost its connection to Yampa.