Senior Flutter Developer / Mobile Team for Production iOS & Android Career App

We are planning a future production mobile application for an existing maritime career platform and are looking for an experienced Senior Flutter Developer / Flutter Lead or a small specialised mobile team. Important: development is not starting immediately. At this stage, we are conducting technical market research and requesting a preliminary budget range, timeline and assessment from experienced candidates. Shortlisted candidates may later be invited to a paid Technical Discovery before the full development contract. The existing platform already includes a Telegram Bot + Mini App, backend/database, admin tools and core business logic. The future iOS/Android application should reuse this backend/API rather than become a separate system. Expected mobile scope The future production MVP is expected to include: * Personalised maritime jobs feed * Search, filters and saved jobs * Backend-provided Match Score / Eligibility / Readiness information * Job detail and recommendation explanations * Application history and follow-up workflow * Integration with existing application/email logic * Maritime Career Profile and Sea Service * Active CV, preview/export and vacancy-specific CV improvements * Secure document vault * Camera/file upload for PDFs and images * OCR with user review/confirmation * Certificate/document expiry reminders * Biometric protection for sensitive documents * Context-aware AI integration through backend services * Push notifications and exact deep links * Apple StoreKit subscriptions * Google Play Billing * Unified subscription entitlement with existing web/Stripe users * Offline/weak-connectivity caching for selected data * English and Russian localisation * Analytics and crash monitoring * App Store and Google Play production release The application may process sensitive maritime documents such as Passport, Seaman’s Book, CoC, Medical and professional certificates, so mobile security and production experience are important. Technology Preferred: Flutter / Dart — iOS + Android We are open to technically justified recommendations, but Flutter is currently our preferred architecture. Please assume for this preliminary estimate that the core backend already exists and a documented API will be available. If you believe additional mobile-specific backend work will be required, estimate it separately. Professional Figma UX/UI will be prepared before final development. Please state whether your estimate assumes UX/UI is supplied by us or included by your team. Experience we are specifically looking for Please apply only if you have relevant published production mobile applications. Experience with several of the following is strongly preferred: * Flutter architecture for complex applications * REST/API integration * Secure authentication * Offline/cache architecture * Camera/document scanning * OCR * Secure file storage * Keychain / Android Keystore * Biometrics * Push notifications * Deep links * Apple StoreKit * Google Play Billing * Backend subscription entitlement synchronisation * CI/CD * TestFlight / Google Play testing * Production App Store / Google Play releases Please include in your proposal 1. Preliminary project budget range Assuming the backend/API is largely ready: USD ___ – ___ Please give an estimated total mobile project range, not only your hourly rate. 2. Estimated timeline How many weeks/months would you expect for a production MVP of this scope? 3. Relevant production apps Please provide 2–4 live App Store / Google Play links. For each, briefly explain what you personally or your proposed team actually built. Screenshots, templates or unpublished demo apps are not sufficient. 4. Team Would you work alone or with a team? Please identify who would cover: * Flutter/mobile development * QA * UX/UI if applicable * release/support 5. Technical risks Please identify the 3 biggest technical or cost risks you see in the project based on this description. We prefer developers who identify risks realistically rather than simply saying everything is easy. 6. Architecture In a few sentences, explain how you would approach architecture for: * API-driven application * offline caching * secure documents * subscriptions Ownership requirements Please confirm that you are comfortable with the following: * Client-owned GitHub/GitLab repository from the beginning * Source code committed throughout development * Client-owned Apple Developer / App Store account * Client-owned Google Play account * Client-owned production cloud/accounts * Project-specific deliverables transferred to the client under contract * No mandatory vendor lock-in Current project stage This is currently a budgetary assessment and candidate research stage, not an immediate development start. The full specification, architecture details and confidential product information will only be provided to shortlisted candidates under NDA. Shortlisted candidates may first receive a paid Technical Discovery assignment before the full development contract is awarded. Please start your proposal with the words “FLUTTER PRODUCTION” so we know you have read the full description.