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Version: v1.16.0

Refined

What is Refined?​

Refined is Newtype + validation. It lets you model validated domain values as types instead of using raw primitives everywhere.

A refined value keeps:

  • the original value type (String, Int, etc.)
  • validation logic (predicate)
  • a clear error message (invalidReason)

Import​

import refined4s.*

Why Use Refined Types?​

  • Avoid primitive obsession by modeling domain meaning in the type.
  • Catch invalid literals at compile-time when possible.
  • Keep runtime validation explicit and total with Either.
  • Make boundaries safer without sacrificing plain Scala values.

More About Refined Types:​