Form validation guidelines
Validation error text
Validation messages are needed when the user input differs from what the system expects and enforces:
- Required fields that are still blank.
- Invalid values, for one or several reasons (forbidden characters, formatting, duplicate).
Use clear language that helps users understand what they have to do.
Name is required.
Do: Use a simple, minimalist format for a required field.
This address is already used. Enter a different one.
Do: Tell users what happened and how to fix it.
The key can't contain the `:` character.
Do: Be as precise as possible to describe the problem.