Social Networking App for Multiple OS

I'm looking for an experienced app developer who can design and build a social networking app compatible with iOS, Android, and Windows. Since the main purpose of the app is social networking, it is crucial that the freelancer possesses expertise in constructing interactive features, user-friendly interfaces, and excellent security measures. Seeing as I skipped the question on design style, feel free to apply your creative discretion on the look and feel of the app. I look forward to collaborating with you to bring this project to life. Ideal skills you need to have include:

- Experience in app development for iOS, Android, and Windows
- Proficiency in social networking app designing
- Strong understanding of best practices for app security.