Angular 2 – Async Validator – Username/email availability check

In this post I will show you, how we can create custom async validator to check for email availability, same logic you can apply for username or other async validations.

Lets create a component:

Here is my user service:

Backed server response for unregistered email will be null and for registered email address will be as shown below –

I hope you like this Post, Please feel free to comment below, your suggestion and problems if you face - we are here to solve your problems.


I am Arjun from Hyderabad (India). I have been working as a software engineer from last 7+ years, and its my passion to learn new things and implement them as a practice. Aside from work, I likes gardening and spending time with pets.

  • Mahaveer Choudhary

    great tutorial keep it up

  • Adrian Dobrowolski

    I got There is no directive with “exportAs” set to “ngModel”

    • Just added the demo files, download it and check. Protection Status