ВАКАНСІЯ ДЛЯ УКРАЇНСЬКИХ IT ФАХІВЦІВSenior Full-Stack Developer - Mobile Media-Tech• React Native, Mobile Apps• Proven experience in building streaming services is must-have.📍 EU, Ukraine🌍 Remote💼 Permanent💲 Compensation is negotiable🗣 English C1CompanyVertical TelevisionPositionSenior Full-Stack DeveloperProjectBuilding the future of Vertical Television by combining cinematic storytelling with interactive, vertical-first technology. The role focuses on a high-scale mobile app and operational web platforms, scalable application design, and performance optimization.Tech Stack• React Native• React• JavaScript• HLS• StreamingKey Responsibilities • Architect, plan, and lead the development of the mobile app built with React Native and web platforms using React, ensuring a holistic and scalable system design.• Own the core viewing experience featuring an infinite vertical video feed with instant time-to-first-frame, video preload/prefetch, player-instance recycling, and disciplined memory management across multiple concurrent video players.• Serve as the technical expert and mentor for mid-level developers by providing guidance, conducting code reviews, and elevating engineering standards within the team.• Adhere to coding standards, best practices, and promote a reusability-first mindset to maintain a clean, maintainable, and highly scalable codebase.• Address complex performance challenges including app state management, native bridging, and video rendering optimizations such as player tuning, reducing frame drops, minimizing jank on scroll, and improving cold-start times.• Design and integrate in-app purchases, subscriptions, deep links, attribution, and user-behavior tracking end-to-end, including client SDK implementation and server-side receipt validation.• Work closely with Product, Design, and Backend engineering teams to deliver fast iterations of complex features in a dynamic startup environment. Required Skills• 8+ years of experience with React Native and React on mobile platforms.• Proven experience in building streaming services.• Experience in video streaming technologies (HLS, DASH or similar).• Experience in native mobile development (Swift, Kotlin) for performance optimization and seamless playback.• Experience in in-app monetization, authentication, and analytics integration.• Experience in fast-paced media-tech startups, driving technical standards, mentorship, and cross-functional collaboration. Nice to Have • Solution Architecture Design.• Apache Spark Streaming.• TypeScript.• Swift.• Kotlin.• Objective-C.• Dash.• ExoPlayer.• Bitmovin.• Mux.• AWS CloudFront.• Fastly.• AWS Cognito.• Crashlytics.• Auth0.• StoreKit.• Billing.• Universal apps.• MongoDB.• AWS.• GCP.• Amplitude.• Mixpanel.• Sentry.• Fastlane.• Detox.• Ffmpeg.• AWS IVS.• AVPlayer.• Experience with mobile CI/CD and release operations.• Background in high-growth startups or mobile entertainment products, with familiarity in vertical/short-form feed products similar to TikTok, Reels, or Shorts.• Understanding of ad-tech and SSAI (AdMob, Google IMA) and subscription monetization modeling.• Knowledge of DRM technologies (Widevine, FairPlay), offline downloads, and transcoding pipelines (Mux, AWS MediaConvert, AWS IVS). Contract• PermanentFormat• Remote (EU, Ukraine)Schedule• Flexible schedule• Long-term engagement• Remote-firstSalary Range💲 Compensation is negotiableHow to ApplyAgency: Upstaff📩 @mariiaemll📢 Ти рекрутер або маєш вакансії у своїй команді? Пиши @uait_contact_bot – опублікуємо безкоштовно.🇺🇦 UA IT-спільнота в Чехії🇨🇿 → @uaitinczech