What are the key features and challenges to consider when developing a salon app?

I’m in the process of developing a salon app and am looking for insights from experienced developers or salon business owners. What are the essential features that must be included in a salon app? Should I focus on appointment scheduling, online payments, or customer loyalty programs?

Additionally, what are some common challenges or pitfalls to watch out for when building such an app? For example, how can I ensure smooth integration with payment gateways, or how can I make sure the app provides a seamless experience for both salon staff and customers?

If anyone has any advice on making the app user-friendly, or any tools and technologies that can speed up development, it would be greatly appreciated!