First 3 months of probation period you will work remotely and after you need to relocate to Madrid and work onsite in office every day. Client provide local relocation support. We are looking for an experienced Senior / Lead Flutter Engineer to lead the architecture, design, and development of advanced mobile applications for iOS and Android. This role combines hands-on engineering with technical leadership, ownership of mobile architecture, security best practices, and mentorship of the development team. You will work closely with product, design, and backend teams to deliver secure, scalable, and high-performance mobile solutions in a complex, real-time, and compliance-driven environment.
Details Employment Type: Full-time Work Format: Onsite in Madrid office English Level: Fluent Start: ASAP
Relocation in 3 months; Client provide relocation support
Key Responsibilities Lead the architecture, design, and development of Flutter applications for iOS and Android Build and maintain secure and scalable authentication systems, including:
- OAuth2 / OpenID Connect
- PKCE flows
- Multi-factor authentication (MFA)
- Secure token lifecycle management
- Role- and permission-based access control
Integrate external APIs, real-time data pipelines, payment systems, and compliance-related services Establish and enforce mobile security best practices:
- Certificate pinning
- Secure local storage
- Encryption strategies
- Secure session management
Collaborate with product managers, designers, and backend engineers to plan and deliver high-impact features Perform advanced debugging, performance tuning, and code optimization Review code and enforce engineering standards and modern Flutter architectures (Bloc, Riverpod, Clean Architecture) Oversee release processes and ensure stable deployments to the App Store and Google Play Evaluate and introduce new tools, frameworks, and technologies to improve development efficiency Mentor junior and mid-level engineers and provide technical leadership and guidance
Required Qualifications Bachelor's degree in Computer Science, Software Engineering, or equivalent practical experience 5–7+ years of mobile development experience 3+ years of hands-on Flutter experience Proven experience building production-grade mobile applications in regulated or security-sensitive domains Strong expertise in authentication, authorization, and identity management solutions Solid understanding of:
- Clean Architecture and SOLID principles
- State management (Bloc, Riverpod, or similar)
- REST and GraphQL API integrations
Experience with mobile CI/CD pipelines (e.g., Codemagic, GitHub Actions, Bitrise) Strong understanding of secure coding practices and compliance requirements Familiarity with backend concepts such as microservices and containerized environments Strong leadership, decision-making, and problem-solving skills Ability to work independently and drive solutions end-to-end
Nice to Have Experience with payment integrations and financial APIs Knowledge of cloud platforms (AWS, GCP, Firebase) Experience with real-time systems (WebSockets, webhooks, event-driven architectures) Experience with monitoring, analytics, and experimentation frameworks Previous tech lead or team lead experience