Immutable database and Datalog query engine in ClojureScript

Immutable, reactive Flux architecture. UI Agnostic.

Efficient, Immutable, Thread-Safe Collection classes for Ruby

A robust library to handle immutable big numbers inside PHP applications

T4 template for immutable type generation

super-opinionated, yell-at-you-for-everything, immutable Flux framework

Scala event-sourcing libary

Flux with immutable data and pure action handlers

easily add # -*- immutable: string -*- comments to the top of all your project's .rb files