Spectra.jl is a package aimed at helping spectroscopic (Raman, Infrared, Nuclear Magnetic Resonance, XAS...) data treatment written with the Julia programming language (http://julialang.org/). It's aim is to provide the simplest way to perform actions like baseline fitting and removal or peak fitting for instance, while respecting the freedom offered by data treatment through coding. Therefore, Spectra.jl is aimed to be used explicitly with other packages like JuMP for building models (see http://www.juliaopt.org/ for further details on optimisation under Julia). The key is to provide functions for simplifying the life of the spectroscopist, while still leaving him all the freedom offered by treating data with a performant computer language