Errors: model them once, catch them once

Fri, 23 Oct 2026 00:01:28 +0200

Errors: model them once, catch them once

Modeling errors in a useful, standard way is really important. An error has two goals:

Tell the user (or the client) what is wrong, so they understand it and maybe can fix it themselves.
Make debugging easy for you.

This post shows how to design errors for both goals: a schema, one way to propagate them, a few rules on where to catch them, and one place to log and render them. The main examples come from an Elixir/Phoenix backend, with a short JavaScript version at the end.

Logging on Buro notes

Errors: model them once, catch them once

Errors: model them once, catch them once