API Development for Multi-Platform App

I am in need of an experienced developer to create a SOAP API for my upcoming app. The app will be available on iOS, Android, and the Web, handling critical data such as user authentication, product information, and transaction data.

Key Requirements:
- Proficiency in developing SOAP APIs
- Experience in creating APIs for multi-platform apps
- Understanding of handling user authentication, product information and transaction data in APIs
- Knowledge of iOS, Android and Web app development