Senior Software Engineer at IO Associates, England, £500-£550 per day

Senior Backend Engineer - Node.js/TypeScript

12-Month Contract | Fully Remote | Outside IR35

We're looking for a Senior Backend Engineer to join an exciting fintech business, working on highly scalable, mission-critical financial systems.

The role is heavily focused on Node.js, TypeScript and AWS, with genuine ownership across the full lifecycle — from system design and architecture through to development, release and production support.

You'll have the opportunity to work on new products and capabilities from an early stage, making key technical decisions and helping shape how the platform evolves.

• Design, build and operate reliable, scalable Back End services
• Own areas of the platform, including architecture and technical direction
• Build resilient APIs and distributed systems within a regulated financial environment
• Work with AWS serverless technologies, including Lambda, SQS, EventBridge and API Gateway
• Work with MongoDB and document databases
• Contribute to CI/CD, observability, incident management and production support
• Work closely with Product, Engineering and Operations to turn business requirements into scalable solutions
• Mentor engineers and contribute to engineering standards and best practice

• Strong Node.js & TypeScript
• Strong system design and architecture
• AWS & Serverless
• MongoDB/document databases
• Distributed systems, observability and incident management
• CI/CD and production operations
• Experience working in a regulated environment, ideally FinTech or financial services
• Comfortable owning services within a build-and-run environment

This is a genuinely hands-on senior role with significant autonomy, where you'll be expected to think beyond the code and consider scalability, resilience, operational impact and customer needs.

If this role sounds like it would be of interest to you or anyone in your network, then apply to this advert and reach out to a. methula@ ioassociates.co. uk