Best approach for building a simple mobile account management service?

Hello,

I’m exploring different approaches for building a simple web-based service that helps users manage mobile account-related tasks, such as checking account information, viewing payment details, and handling recharge-related actions.

For a project like this, would a REST API-based architecture be the best approach? I’m also interested in learning how developers typically handle authentication, user data security, and integrations with external service APIs.

What architecture or technologies would you recommend for building a reliable and user-friendly service?

Thanks in advance for any advice.