Env Extra

Jets has the concept of extra environments. This can be controlled by the JETS_EXTRA variable. By setting JETS_EXTRA you can create additional identical environments.

jets deploy # first environment demo-dev
JETS_EXTRA=2 jets deploy # creates a demo-dev-2 environment

Interestingly, since AWS Lambda pricing is based on usage. These extra environments cost you pretty much nothing. They’re literally free until you exceed the free tier. Create 10 extra Development, Staging or UAT environments if you need them 🎉


  1. JETS_EXTRA - takes the highest precedence
  2. config/application.rb extra setting - takes lower precedence

Blue-Green Deployments

With the ability to create entire applications with just a variable change, you can use it to perform blue-green deployments.

  1. Create another environment
  2. Test it to your heart’s content
  3. Switch the DNS over to the new stack
  4. Delete the old environment