I am planning to launch a fully featured productivity app that runs smoothly on both iOS and Android. The core idea is to help individuals and small teams stay organised without juggling multiple services, so code quality, intuitive UX, and efficient data synchronisation matter as much as the features themselves. Scope of work You will build the mobile application end-to-end, covering UI/UX, front-end, back-end, and store submission. I am flexible on the tech stack—Swift / Kotlin, Flutter, or React Native—as long as the final builds feel truly native and the codebase is clean and maintainable. Key features to be delivered • Task management with due dates, priorities, and push reminders • Calendar integration that syncs with native device calendars in real time • Collaboration tools such as shared task lists, comments, and basic role permissions Nice-to-haves (let me know if you can include them) could be offline mode with background sync, dark-mode support, and simple analytics for user engagement. Acceptance criteria 1. Both App Store and Google Play builds approved under my accounts. 2. All three core features working consistently across platforms. 3. Source code, build instructions, and brief technical documentation handed over on completion. If you have already shipped similar cross-platform productivity or SaaS apps, please mention them in your proposal along with the frameworks and architecture you prefer. I look forward to collaborating with someone who values clean design and reliable performance as much as I do.