Senior Flutter Engineer (BLE)

We are looking for a Senior Flutter Engineer with strong Bluetooth Low Energy (BLE) experience to join our client's team in a long-term contract engagement. This is a fully remote opportunity to build the core software layer powering a smart locker platform used by enterprise and public sector organisations.

You will take ownership of a Flutter/Dart SDK that acts as the bridge between mobile applications, cloud services, and physical smart locks. The SDK abstracts complex BLE communication, authentication flows, token management, and server interactions behind a clean, high-level API used by partner applications.

This role is ideal for an engineer who enjoys solving real-world connectivity challenges, working close to hardware and firmware systems, and building robust SDKs that operate reliably across diverse mobile environments.

Key Responsibilities:
 

• Design, develop, and maintain a Flutter/Dart SDK used by partner applications to interact with smart locker infrastructure
• Implement BLE scanning, lock discovery, and device identification across iOS and Android platforms
• Manage BLE connection lifecycles, including reconnection strategies, timeout handling, and device-level edge cases
• Build and maintain secure authentication and encrypted token exchange workflows between mobile applications and physical locks
• Implement token sequencing, refresh mechanisms, and rolling token buffer management for allocated lockers
• Integrate with backend services through REST APIs to support locker allocation, availability checks, token issuance, and session validation
• Handle race conditions and real-world concurrency scenarios between multiple apps, users, and physical access methods
• Collaborate closely with firmware engineers to implement and validate communication protocols and authentication sequences

• Ensure SDK reliability, maintainability, performance, and developer-friendly API design

   

Requirements:
 

• 5+ years of commercial Flutter/Dart development experience
• Strong experience building and shipping production mobile applications
• Proven hands-on experience working with Bluetooth Low Energy (BLE) in real-world environments
• Deep understanding of BLE concepts including GATT services, characteristics, device discovery, connection management, and platform-specific behaviours
• Experience supporting BLE functionality across both iOS and Android
• Solid understanding of REST API integration and asynchronous application architecture
• Experience working with secure storage, authentication flows, and token-based systems

• Strong debugging and problem-solving skills, particularly around connectivity issues and device-level edge cases

   

Nice to Have:
 

• Experience building and maintaining Flutter packages or SDKs
• Background in IoT, smart devices, access control, or hardware-integrated applications
• Familiarity with cryptography, encryption protocols, and secure communication patterns
• Experience collaborating with embedded or firmware engineering teams
• Knowledge of mobile platform internals related to Bluetooth and background processing
• Experience designing public-facing APIs for external developers
   

What We Offer:
 

• Fully remote engagement with flexible working arrangements
• Opportunity to build a core product used by enterprise and public sector customers
• Challenging technical work involving mobile, cloud, BLE, security, and hardware integration
• High level of ownership and autonomy with direct impact on product architecture
• Collaborative engineering environment with close interaction between mobile, backend, and firmware teams
• Competitive compensation based on experience and expertise

How to Apply:

Send us a short intro about yourself and your relevant experience - and tell us your favourite ice cream flavour (ours is cherry🍒)