Adding your existing Julia code into Genie apps

If you have existing Julia code (modules and libraries) which you'd like to quickly expose on the web without building an app from scratch, Genie provides an easy way to add and load your code into an app.

Adding your Julia code to a Genie app

If you have an existing Julia application or standalone codebase which you'd like to expose over the web through a Genie app, the simplest thing is to add the files to the lib/ folder. The lib/ folder is automatically added by Genie to the LOAD_PATH, recursively.

This means that you can also add folders under lib/, and they will be recursively added to the LOAD_PATH. Beware though that this only happens when the Genie app is initially loaded. Hence, an app restart might be required if you add nested folders after the app is started.


In most cases, Genie won't create the lib/ folder by default. If the lib/ folder is not present in the root of the app, just create it yourself:

julia> mkdir("lib")

Once your code is added to the lib/ folder, it will become available in your app's environment. For example, say we have a file called lib/MyLib.jl:

# lib/MyLib.jl
module MyLib

using Dates

function isitfriday()
  Dates.dayofweek( == Dates.Friday


Then we can reference it in routes.jl and expose it on the web as follows:

# routes.jl
using Genie.Router
using MyLib

route("/friday") do
  MyLib.isitfriday() ? "Yes, it's Friday!" : "No, not yet :("

Use the lib/ folder to host your Julia code so that Genie knows where to look in order to load it and make it available throughout the application.