Comprehensive Business App Development

I'm looking to develop a robust application that integrates several key systems to enhance my business operations. The app will include a quotation system, billing system, geolocalization for employees visiting customers, a derating system, and a chat system for communication between customers and workers. Additionally, there will be a website component to allow users to access their accounts from a computer.

Key Requirements:
- Development for both iOS and Android platforms
- Integration of all specified features with equal priority
- A website that complements the app, providing seamless access to user accounts
- A design that is both professional and appealing (NICE & PRO)
- Clear and precise communication throughout the project
- Launch target: September 2025

Ideal Skills and Experience:
- Proven experience in developing multi-functional apps for both iOS and Android
- Strong portfolio showcasing similar projects
- Expertise in integrating complex systems such as billing, geolocalization, and chat
- Ability to design professional and user-friendly interfaces
- Experience in server management and deployment

Please provide your portfolio, a serious and competitive price, your proposed deadline, and your method for server management. I am committed to this project and expect the same level of seriousness from potential freelancers.