Principal Software Engineer - Java

ZipRecruiter; Cambridge; Remote; GBP 70,000 - 90,000; Full time

Job summary

An innovative clean-tech firm is looking for a Principal Software Engineer with Java expertise to lead software design for their SaaS platform. This role offers the chance to influence technical direction in a collaborative environment, supporting the transition to cleaner energy. The position allows for remote work across the UK while offering competitive compensation of £70-90k plus benefits.

Qualifications

• Proven experience in building enterprise-grade Java backend systems.
• Deep understanding of software architecture and patterns.
• Hands-on expertise with DevOps practices.

Responsibilities

• Lead on software design and architecture for a scalable SaaS platform.
• Build cloud-based Java microservices.
• Drive continuous improvement in engineering culture.

Skills

Java/Microservices backend systems

Cloud development with AWS

Distributed systems/Kafka/event-driven systems

Software architecture, scaling/resilience

DevOps practices (Kubernetes, Terraform)

Startup mindset

Tools

Spring Boot

Micronaut

CI/CD

Gitlab

Job description

Overview

Principal Software Engineer with a Java Back End/full-stack experience to take a lead role in designing and architecting the SaaS platform for an early-stage clean-tech startup on a mission to accelerate the shift to a greener energy world by optimising complex grid-scale battery assets for asset owners through data, ML, and SaaS innovation.

Proximity to Cambridge would be ideal, although a remote role across the UK/with some company meetups.

Salary £70-90k + Bens + Options

Key skills you will bring as a Principal Software Engineer

• Proven track record in building enterprise-grade Java/Microservices backend systems (Spring Boot or Micronaut)
• Cloud development ideally with AWS
• Proven experience in distributed systems/Kafka/event-driven systems
• Deep understanding of software architecture, patterns, scaling/resilience and ideally with domain-driven design
• Hands-on expertise with platform engineering/DevOps practices (Kubernetes, Terraform, containers, CI/CD, ECS, Gitlab etc)
• A proactive, startup mindset with the ability to balance strategy and execution

Nice to have skills

• Experience with Front End UI design and Front End development (MUI/React/JavaScript/TypeScript)
• Familiarity with Data Engineering patterns, Data Products/Kafka streams, and Data Pipelines
• Experience with platform-as-a-product delivery or platform engineering
• Familiarity with Machine Learning Engineering tools and frameworks
• Experience with microservice networking and service meshes (such as Istio)
• Well-informed on security considerations in a cloud environment, with prior experience with related tooling (eg OPA, IRSA)
• Experience of working within startup environments

What you'll be doing as a Principal Engineer

• Lead on software design, architecture, and coding to shape a scalable, resilient full-stack SAAS platform
• Build cloud-based Java microservices (Spring Boot/Micronaut) and drive engineering practices
• Drive continuous improvement in engineering culture, mentoring/coaching other engineers and guiding technical decisions
• Collaborate across product, engineering, and customer teams to deliver impactful solutions to the SaaS platform

You'll bring strong software engineering practices to a fast-moving, collaborative environment, setting technical direction while staying hands-on with code within a small, focused cross-functional team.

Why join? This is a rare opportunity to be part of the early days of a high-growth renewable energy startup, shaping both the product and the engineering culture. You'll have the freedom to make architectural decisions that matter - while contributing directly to the clean energy transition.

Cambridge-based office, with flexibility to work fully remote across the UK.

Interested? Apply now or reach out to Opus Resourcing for more details.