Senior Secure Mobile Engineer (Flutter)

About the Role

We are looking for a Secure Mobile Engineer (Flutter) to join a Client’s team building a Zero-Knowledge mobile product.
This role is security-critical: the mobile app handles encryption, key management, and sensitive data locally — meaning client-side security is the core of the system.

👉 Our priority is a Senior-level engineer, but we are also open to strong Middle candidates with solid security fundamentals and growth potential.

Location: Remote
Cooperation Type: Full-time, long-term
Experience Level: Senior / Middle
Start: ASAP

Responsibilities

• Design, develop, and maintain a secure Flutter mobile application (iOS & Android)
• Implement client-side encryption, key generation, and secure session handling
• Work with Swift / Kotlin via platform channels
• Implement secure local storage using iOS Keychain, Android Keystore, and encrypted SQLite (SQLCipher)
• Apply memory hygiene practices to prevent sensitive data leaks
• Implement certificate pinning and protect against MITM attacks
• Build privacy-first features aligned with Zero-Knowledge security principles
• Work on on-device processing and AI features (offline inference where applicable)
• Collaborate with backend and security teams to ensure end-to-end system security
• Participate in architecture discussions and security reviews
• Write clean, testable, and well-documented code

Requirements

• 4+ years of mobile development experience with Flutter / Dart
• Strong hands-on experience with Flutter in production apps
• Experience with mobile security and secure data handling
• Understanding of applied cryptography and encryption principles
• Experience with iOS Keychain and Android Keystore
• Experience implementing secure local storage (SQLCipher / encrypted SQLite)
• Experience working with Swift and Kotlin via platform channels
• Experience with state management (BLoC or Riverpod)
• Experience implementing certificate pinning and network security
• Ability to work on security-critical features and privacy-first systems
• English: Intermediate or higher

Nice to Have

• Experience with Signal Protocol or MLS
• Experience with Zero-Knowledge systems
• Experience with on-device AI (TensorFlow Lite, MediaPipe, on-device LLMs)
• Experience with Tor / Orbot or anonymous routing
• Experience with advanced mobile OS security or threat modeling

What We Offer

• Competitive compensation according to your experience (gross system)
• Fully remote work and long-term cooperation
• Opportunity to work on a high-security, privacy-first product
• Direct impact on core security architecture
• Fast hiring process and quick start
• Supportive engineering culture focused on quality, ownership, and security

What happens after you apply

• Quick CV review
• Short recruiter call
• Technical interview with LITSLINK team
• Fast decision & offer