I need a complete cross-platform mobile marketplace that runs smoothly on both iOS and Android. The app will open with two distinct portals: one tailored to sellers, the other to buyers. On the buyer side I must be able to browse the full catalogue with fluid search and category filters, select a suitable offer, and then pay through a secure, widely-supported gateway. For the seller experience, I want a straightforward dashboard where products(services) can be uploaded, edited, and orders monitored in real time.More than that,the app should be user friendly,not complicated.Finally, this app should based on a win to win strategy so a requirment is a bonus offer to be used for both parties Code-sharing frameworks such as Flutter or React Native make sense to keep the build economical, but I am open to your preferred stack as long as the final binaries reach both App Store and Play Store without compromise. Please outline: • the toolset you propose (language, framework, back-end, payment API) • the milestones you recommend from prototype to store submission • the testing approach you will follow for both OS versions I am looking for precise, cost-effective offers that cover development, basic UI/UX, and post-launch bug support so we can get this marketplace live quickly and reliably.