On-Demand Delivery App Development

I'm seeking an experienced app developer to create an on-demand delivery app for packages and small goods. The app will connect customers with independent couriers for same-day or urgent deliveries.

Key requirements include:
- Platforms: iOS, Android, and Web
- User Roles: Customer, Courier, and Admin
- Delivery Speed: Same-day delivery
- Key Features: Real-time tracking, choice of delivery speed, integrated payments, route optimization, and courier app integration

Ideal Skills and Experience:
- Proven experience in developing multi-platform delivery apps
- Strong understanding of real-time tracking and route optimization technologies
- Expertise in payment integration and app security
- Familiarity with user experience design for seamless navigation

Please provide a portfolio of similar projects and an estimated timeline for completion.