So you want to develop a DID/OSDD mobile app: A reality check
To even consider this you need to have experience with at least the following:
Graphic Design (for icons, etc)
Human Computer Interaction (user interface design)
Database design and administration. This includes things like migrating to a new schema as the app grows and changes are needed without breaking it for anyone who is using the app.
REST API design and development, this includes things like API Version management so that your app doesn’t break for people who haven’t updated yet.
Backend / server development
Mobile UI development whether that’s jetpack compose or swift UI or whatever applies to the platforms you are targeting.
Programming In Kotlin, java or swift (depends on platform)
Writing and running automated tests
Server administration or cloud dev ops
Release management, which includes google play / app store polices and requirements.
(if targeting both iOS and android) cross platform development experience
Bug tracking / Project management
Backup and Disaster recovery.
Security (this includes incident response when your app gets hacked, which it will eventually).
Legal and Compliance (DID/OSDD related data could be considered health data and is subject to laws about how data is processed and stored in certain countries, which the vast majority of DID/OSDD apps are probably breaking).
Developing bug fixes and updates (google play requires an app to be updated every so often or it will be removed, I am unsure as to what apple’s policies are)
Fixing security vulnerabilities (yes you will have them)
That’s a lot of skills for one person to have. I have assumed that you are already an advanced programmer in at least one programming language. That’s not enough.
All of these things take a lot of time, and you only have one body.
You probably also already have a full time job.
In an actual software company, there would be a full-time employee responsible for each of those areas who specializes in doing just that.
There is a reason all the apps developed by a single person don’t work properly.
There is no such thing as a full stack developer anymore, there hasn’t been for years.