Key insights
- Validating on submit is too late — users fill ten fields, commit, then get hit with a wall of errors all at once.
- Validating on every keystroke is too early — it flags a field as wrong before they've even finished typing the word.
- The sweet spot is on blur: check a field the moment focus leaves it, so feedback lands after they're done but before they submit.
- Once a field has errored, switch to live validation for that field so the error clears the instant they correct it.
- Success is feedback too — a green check tells users a field is right, not only when something's wrong.
Do / Don't
- Do: Validate a field on blur, once the user has moved on from it.
- Do: After a field errors, revalidate live so the message clears the moment it's fixed.
- Do: Confirm correct fields with a green check, not just flag the broken ones.
- Don't: Hold every error until submit and reveal them all at once.
- Don't: Fire red errors on each keystroke before the user finishes typing.
