Senior Software Engineer

iO Associates; Bath; On-site; GBP 75,000 - 105,000; Full time

Job summary

iO Associates is seeking a Senior Backend Engineer to join a fast-growing fintech business operating in a highly regulated environment. You will own backend design, architecture and production systems, aiming for scalable, resilient services and robust incident handling.

Collaborating with Engineering, Product and Operations, you will drive CI/CD, observability and reliability improvements across a suite of business-critical platforms.

Qualifications

• Senior backend experience with TypeScript and Node.js.
• Experience in system design and building scalable, resilient architectures.
• Strong AWS experience (Lambda, API Gateway, DynamoDB and MongoDB).
• Knowledge of automation, CI/CD, and modern engineering practices.
• Experience in scale-up environments; fintech or regulated contexts is a plus.

Responsibilities

• Own system design, architecture, CI/CD, observability, incident response and production systems.
• Collaborate with Engineering, Product and Operations to improve reliable platforms.

Skills

TypeScript

Node.js

System design

AWS

CI/CD

Observability

Scale-up experience

Fintech/regulatory experience

Job description

Up to £75,000 to £105,000 per annum (D.O.E)

Senior Software Engineer is required to join a fast-growing technology business operating within the highly regulated financial services sector. The organisation is looking for genuinely senior backend engineers who can design scalable, resilient systems and take ownership beyond simply delivering tickets.

You will take ownership across system design, architecture, CI/CD, observability, incident response and production systems, working closely with Engineering, Product and Operations teams to build and continuously improve reliable platforms.

Required Skills:

• Strong backend engineering experience with TypeScript and Node.js
• Proven experience in system design, architecture and scalable, resilient systems
• Strong AWS experience, including Lambda, API Gateway, DynamoDB and/or MongoDB
• Strong understanding of automation, CI/CD and modern engineering practices.
• Experience working within a scale‑up/growth environment
• Financial services, Fintech or regulated-environment experience would be advantageous

If you’re a Senior Backend Engineer looking for a role with significant ownership, technical influence and the opportunity to work on business-critical systems, we’d love to hear from you.