Full Stack Engineer 200968

Harnham; Greater London; On-site; GBP 90,000 - 130,000; Full time

Job summary

Harnham is hiring a foundational software hire at an early stage. You will own major software systems spanning mobile apps, cloud infrastructure, and device connectivity, shaping long-term software strategy while partnering with senior stakeholders.

You will build across iOS/Android, BLE-integrated devices, and AWS-based backend services, driving data pipelines and AI-driven features while maintaining high-quality, scalable software as the business scales.

Qualifications

• Experience building and shipping production software.
• Experience developing and deploying mobile applications.
• Hands-on BLE connectivity with devices.
• Strong knowledge of AWS cloud services, infra, auth, and data systems.
• Full stack development across frontend, backend, and infra.
• Experience leveraging AI tools to enhance product experiences.
• Comfortable in fast-moving environments with ownership.
• Strong communication across technical and non-technical teams.
• Experience in health tech, regulated data, or sensitive data apps.
• Experience with IoT platforms and connected device ecosystems.

Responsibilities

• Build and maintain mobile apps across iOS and Android.
• Develop and optimise BLE connectivity between devices and apps.
• Design and manage AWS-based cloud infrastructure and backend services.
• Create scalable data ingestion and processing pipelines.
• Support integration of AI-driven features in products.
• Own software quality, observability, deployment and releases.
• Collaborate with product and engineering to turn requirements into production code.
• Contribute to growth and development of the software function as the company scales.

Skills

Production software

Mobile development

BLE connectivity

AWS cloud

Full stack development

AI tools integration

Ownership mindset

Cross-functional collaboration

Health tech / regulated data

IoT ecosystems

Tools

BLE

AWS

Frontend frameworks

Job description

This is a rare opportunity to join an early-stage technology business as a foundational software hire. You will have significant ownership from day one, working across mobile, cloud, and connected device technologies while helping shape the long-term software strategy and engineering function.

The Company

They are an innovative technology business developing connected products that combine hardware, software, and data to deliver meaningful real-world impact. Their product is already in market with a growing user base and a clear roadmap for future growth. The team is highly collaborative, technically strong, and focused on building solutions that genuinely improve customer outcomes. You will join at a pivotal stage, with the opportunity to influence both product direction and technical decisions.

The Role

You will take ownership of key software systems across mobile applications, cloud infrastructure, and device connectivity, working closely with senior stakeholders and technical teams.

Responsibilities include:

• Building and maintaining mobile applications across iOS and Android platforms.
• Developing and optimising Bluetooth Low Energy (BLE) connectivity between devices and applications.
• Designing and managing AWS-based cloud infrastructure and backend services.
• Creating scalable data ingestion and processing pipelines.
• Supporting the integration of AI-driven functionality into customer-facing products.
• Owning software quality, observability, deployment, and release processes.
• Collaborating with product and engineering teams to translate requirements into production-ready solutions.
• Contributing to the growth and development of the software function as the business scales.

Your Skills & Experience

• Strong commercial experience building and shipping production software.
• Proven experience developing and deploying mobile applications.
• Hands-on experience working with Bluetooth Low Energy (BLE) connected devices.
• Strong knowledge of AWS cloud services, infrastructure, authentication, and data systems.
• Full stack development capability across frontend, backend, and infrastructure.
• Experience leveraging AI tools and understanding how AI can enhance product experiences.
• Comfortable operating in fast-moving environments with high levels of ownership.
• Strong communication skills and the ability to collaborate across technical and non-technical teams.
• Health technology, regulated environments, or sensitive data applications.
• IoT platforms and connected device ecosystems.
• Time-series data, signal processing, or analytics-focused products.
• Over-the-air firmware updates.
• Mentoring engineers or contributing to technical leadership.
• Early-stage startup or scale-up environments.

What They Offer

• Genuine ownership of a core product and technology stack.
• Significant exposure to senior leadership and strategic decision-making.
• Clear progression into technical leadership as the company grows.
• Opportunity to help shape engineering culture, processes, and future hiring plans.