This is the primary question that you should ask yourself, What is my project all about?

Defining the solution you want to build will allow you to hire developers for startup in the right direction.

Are you targeting mobile users, web users, or both?

Developing a digital solution for mobile and web will require native tools to build.

For a solution that will run on mobile and web, you need a developer who knows about hybrid development technologies.

React NativeXamarinFlutterIonic

Within the purview of Mobile solutions, you may need to decide between Android or iOS.

There are no overlaps in the application development. You cannot expect an android developer to build an extensive and native iOS application.

The same holds the other way around.

Apart from this, both the iOS and Android application development requires a different SDK.

That is why it is crucial to find the platform on which you will run the app before knowing how to hire a programmer for a startup.