I’m ready to commission a cross-platform mobile marketplace where people can post physical-product listings and potential buyers can reach sellers instantly through either WhatsApp or a direct phone call. Product categories must be built in from day one so items are easy to browse. Here’s what I need from you: • A clear timeline estimate that covers design, development, testing, and release • A cost breakdown per phase or milestone • Your recommended technology stack (whether native, Flutter, React Native, etc.) and why it fits this project • Full support for submitting to both the Apple App Store and Google Play, including compliance checks and store assets • A post-launch maintenance plan outlining how you handle bug fixes, minor updates, and version upgrades Core features to develop: • User accounts with the ability to create, edit, and delete physical-product listings • Category-based browsing and search • “Chat on WhatsApp” and “Call Seller” buttons on every listing, automatically opening the chosen channel with the seller’s number • Basic analytics and crash reporting hooks so we can monitor performance from day one When you reply, please attach the requested timeline, budget breakdown, and stack details. If you’ve shipped similar marketplace or classified apps, a short link or store reference will help me gauge fit. Looking forward to your plan and seeing how you’d bring this app to both iOS and Android users smoothly.