TikChecker

TikChecker allows you to check if your brand, business, product, personal name or username is available. 

Using the app is very simple. Type an username in the text field and click on "Search" button. The app will show if the username exist or not. If it does not exist, the app will list some suggestions of usernames that you can try.
The app also saves the usernames in case of you want to check it again. 

I hope you enjoy this app.