Senior Mobile Developer (Flutter)

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Senior Mobile Developer (Flutter) based in Spain. This is a high-impact opportunity to own the mobile experience of a digital retail ecosystem used in demanding, real-world store environments. You’ll build a high-performance mobile application connecting directly with payment terminals, printers, barcode scanners, and other specialized hardware. The role goes beyond conventional app development, combining Flutter with native Android/iOS capabilities through an Add-to-App architecture. You’ll help deliver critical features spanning point-of-sale, billing, inventory, banking, B2B commerce, and AI-powered user assistance. A strong focus on offline-first architecture, reliability, speed, and seamless checkout experiences makes this a technically challenging role. You’ll work closely with Product and Backend teams in a fully remote, international environment where autonomy and ownership are highly valued. It’s an excellent fit for an experienced Flutter developer who enjoys solving complex technical problems and building products with tangible everyday impact. Own and develop the mobile experience for a mission-critical digital retail platform used in fast-paced store environments. Build and maintain Flutter modules using an Add-to-App architecture, enabling seamless communication between Dart and native Android/iOS SDKs. Develop native integrations with payment terminals, receipt printers, barcode scanners, and other retail hardware. Integrate mobile functionality with Java-based backend microservices through REST APIs. Develop and maintain features across point-of-sale sales and billing, B2B marketplace, banking, inventory management, and AI-powered assistance. Create high-quality, pixel-accurate interfaces from Figma designs, optimized for rapid interaction and busy retail environments. Design and implement robust offline-first capabilities using local storage technologies such as SQLite. Optimize application performance to deliver fast, responsive, reliable, and crash-resistant experiences. Develop and maintain integration tests, particularly for hardware-sensitive and transaction-critical workflows. Establish mobile development best practices, participate in code reviews, and maintain high standards across the codebase. Collaborate closely with Product Management and Backend Engineering to define requirements, plan delivery, and resolve technical challenges. Take ownership of assigned initiatives from planning through implementation and delivery, ensuring high-quality results and dependable timelines. Requirements: 5+ years of professional mobile development experience, including at least 3 years of deep, hands-on Flutter development. Strong expertise in Flutter and Dart, with proven experience using Flutter's Add-to-App architecture. Professional experience with native mobile development, particularly Kotlin/Android or Swift/iOS. Experience integrating mobile applications with external hardware and native SDKs, ideally payment terminals, receipt printers, or barcode scanners. Strong understanding of mobile state management, REST API integration, and local database technologies such as SQLite. Experience building offline-first mobile applications and handling intermittent connectivity reliably. Strong understanding of mobile performance optimization, application reliability, and production-quality development practices. Experience writing Flutter integration tests and testing hardware-dependent application flows. Ability to translate detailed design specifications into polished, high-quality mobile interfaces. Strong organizational and time-management skills, with the ability to work independently, prioritize effectively, and meet deadlines. Excellent communication skills and confidence collaborating with product, engineering, and other stakeholders in an international environment. Professional flue