To get the Bullet gem running correctly on a Sinatra app.

Add bullet to your gemfile.

gem 'bullet', require: false

Then in either your config.ru or app.rb. Add the following:

require 'bullet'

Bullet.enable = true
Bullet.alert = true
Bullet.bullet_logger = true
Bullet.console = true

use Bullet::Rack

Now, if you start your app, you should get warnings from Bullet for any N+1’s or unused eager loading.