Cross-Platform Secure App Build

I’m ready to take an idea from concept to a fully functioning mobile application and I’m looking for someone who can handle every layer of the stack. The end result should be a polished app that runs smoothly on both iOS and Android, complete with a reliable email-and-password sign-in flow and solid security practices throughout.

Front-end
Design and code the user interface so it feels native on each platform. If you prefer Flutter, React Native, or another cross-platform framework, let me know your reasoning and past successes with it. I’m mainly concerned with performance, clean navigation, and accessibility.

Back-end & APIs
Set up all server-side logic, REST or GraphQL endpoints, and any middleware required to power the app’s core features. Latency must stay low, and the codebase should be easy to extend for future features.

Database
I haven’t locked in a specific technology yet—SQL or NoSQL could both work—so I’m looking for your recommendation. Please outline why your choice fits scalability, maintenance, and cost goals.

Security & Authentication
Implement robust email/password authentication, secure password storage (bcrypt, Argon2, etc.), and token-based session management. Protect all data in transit with HTTPS/TLS, enforce strong password rules, and include rate-limiting or other basic abuse protections.

Deployment & Handover
• Cloud deployment pipeline (AWS, GCP, or similar)
• Source control on GitHub/GitLab with meaningful commit history
• Clear README and setup scripts so I can spin up dev or staging environments easily
• Final walkthrough and knowledge transfer

If your proposal briefly covers preferred technologies, timelines, and any comparable apps you’ve shipped, it will help me make a quick decision.