Since the introduction of Mailer Previews and ActiveJob in Rails 4.1, the framework has truly set itself apart from others in the comprehensiveness and comfort of its workflow around emails. The framework’s creator, DHH, has espoused a perspective that mailers are views, and accordingly Rails now gives us an email workflow that is nearly identical to that around ordinary controllers and views.

I will walk through my complete email stack and workflow, which I have used very effectively across several production apps.

Validation contexts are a little-appreciated but immensely practical feature of Ruby on Rails’ object-relational mapper, ActiveRecord. I cannot count the number of times I have seen hacks around a problem for which a validation context would have been a perfect fit simply because this feature lives a bit under the radar and isn’t in every Rails developer’s toolbox.

What is a validation context, precisely? It is a way to constrain a model validation to a particular usage context for a record. This is similar to what you might achieve with something like state_machine, but far more lightweight.