Keep it contained

Keep each mistake inside a small box, so it cannot spread.

  1. Stop 1, next

    One real copy single source of truth

    Think of it when the same fact, such as a price or a rule, is written down in two places.

    StartAbout 3 minutes. The word for it comes at the end.

  2. Stop 2, next

    Simple outside, deep inside deep module

    Think of it when every caller of some code has to know the same many details to use it.

    StartAbout 3 minutes. The word for it comes at the end.

  3. Stop 3, next

    Check at the door boundary validation

    Think of it when data arrives from a user, a file, a config or another company's API, or the same check appears in many places.

    StartAbout 3 minutes. The word for it comes at the end.

  4. Stop 4, next

    Know what it can break blast radius

    Think of it when you decide how carefully to check a change, and how many places to check.

    StartAbout 3 minutes. The word for it comes at the end.