Thank you, I’m happy you liked the article!

Doing inline validation correctly is a complex task, I completely agree with you there. Vitaly Friedman mentioned that feedback often occurs either too late or too early and emphasized the importance of adapting the feedback delay to the type of input field.

I can’t always remember the different input types and appropriate feedback, so I keep a guide by Vitaly Friedman bookmarked to double-check whenever I have doubts: https://www.smashingmagazine.com/2022/09/inline-validation-web-forms-ux/

Also, there is a great usability testing by Baymard Institute https://baymard.com/blog/inline-form-validation