I just faced an amazing tool, called Direnv, which I immediately put in my toolbox. The name reveals the intention - it manages environment variables per folder. It knows how to hook into different shells and load variables from a configuration file just per that particular folder.

Let's install it:

brew install direnv  

Then attach to your shell of choice:

eval "$(direnv hook bash)"  

Now we are good to create a configuration file, where all the variables per directory/project will be stored:

echo export SENDGRID_KEY=SOME_KEY > .envrc  

The format of the file is quite simple. You just export key/value pair. That's it:

export KEY1=<VALUE>  
export KEY2=<VALUE>  

To load the variables run (usually when you edit or add new):

direnv allow  

To summarize there is the following workflow:

• Create .envrc file per project/directory
• Fill .envrc with variable
• Use the variables in the scope of the directory