software systems engineer jobs in Chelmsford

You will be responsible for the entirety of the back end features of the products.

You will be in charge of building scalable backend services and awesome messaging queues.

You will be responsible for developing a Python-based back end platform that's handling 100,000+s of interactions daily.

You will play a critical role in maintaining, improving, and developing PLC-based systems within a heavy manufacturing environment. Key Responsibilities

SOFTWARE ENGINEER REMOTE (OPTION TO RELLOCATE) £110K + EQUITY THE COMPANY This innovative AI startup is redefining safety and reliability in AI models. While competitors like GPT and DeepMind struggle with hallucinations and illegal content generation, this company adds safety control layers to ensure AI outputs are trustworthy and compliant. Working with high-profile, they’re building AI...

You will need to be: - Committed - We're seeking people who are committed to personal development and a new career in Systems Engineering. - Keen to Develop - No matter how good our development programme is, it will require pro-active learning within your role; the faster you learn, the more accelerated your development will be.

Contract – 8 Months Inside IR35 Remote – UK Power Systems Consultant (EMT & RMS Studies) The consultant will support power system projects across multiple phases by delivering high-quality electrical studies and technical documentation. Key Responsibilities - Develop and validate EMT and RMS models for assets such as WTGs, PPCs, and STATCOMs. - Plan and execute design and Grid Code...

Principal Software Engineer Fully Remote | Permanent | Competitive Salary + Benefits Harrington Starr has partnered with a leading Global Payments Technology company who are seeking to hire a Principal Software Engineer to join their senior engineering leadership team. This is a rare opportunity to combine hands-on development with strategic influence, guiding architecture decisions and shaping...

Senior/Lead Software Engineer – Fully Remote (UK) A global B2B SaaS technology business is building out its European engineering hub and is hiring multiple Senior / Lead Software Engineers (JavaScript) to develop and enhance a mission-critical platform used internationally. These are hands-on individual contributor role with strong ownership — ideal for engineers who enjoy building high-quality...

You will be working closely with the Machine Learning team; however, you are not required or expected to have background in Machine Learning. This is an applied role, and we are looking to hire a software engineer with experience in cloud computing and distributed systems. In this role, you will:

Systems Engineer – Photonics & Acoustics Location: Chelmsford, Essex (Hybrid) Salary: £50,000–£65,000 + 2.5% bonus A leading defence organisation is looking for a Systems Engineer to join their Photonics & Acoustics R&D team based in Chelmsford. This is a hands-on, mid-senior role working on rapid prototypes and cutting-edge technologies in photonics, acoustics, sensors, and multi-domain...

You will technically lead ATE projects from concept to deployment, mentoring junior engineers and collaborating with cross-functional teams in hardware, firmware, and manufacturing to enhance product test coverage, throughput, and diagnostic accuracy. Key Responsibilities:

You will design and build APIs that enable products, partners and AI services to work together, including: Building RESTful APIs using C# .

You will likely bring: Strong experience building backend services in C# .

You should be comfortable with most of our core technologies:

Key Responsibilities - Design, implement, and maintain software for nuclear systems, ensuring compliance with safety and regulatory standards. - Develop software for reactor control, monitoring systems, data acquisition, simulation, and predictive analytics. - Collaborate with multidisciplinary teams including nuclear engineers, electrical engineers, and safety specialists. - Apply best...

You will join a cross-functional product engineering team working on the evolution and modernisation of a core SaaS platform. The focus is on building scalable, cloud-native services while improving reliability, performance, and long-term maintainability.

About the Job This position is for a Senior Software Engineer with a minimum of 5 years of experience in backend development and a passion for building robust, scalable systems. We are looking for an engineer with a strong background in the C# .NET ecosystem, and a preference for candidates with significant experience on AWS. Are you ready for a challenge? We’re looking for a dynamic software...

Our client, an operational technology and digital transformation company, is recruiting for a Senior/Lead Protection & Control Systems Engineer to join their business in Staffordshire. Position Title: Senior/Lead Protection & Control Systems Engineer Position Type Permanent Start Date: ASAP Location: Remote from UK Contact: Ashish Rastogi| +44 151 808 1029 Job Description: - As part...

You will be required to be on-site 3 days per week, in Basildon. This is an intial three month project - there is a strong likelihood of extension or movement onto a follow-on project depending on programme need and performance. Required Skills & Experience - Strong experience with C# / .

Principal Software Engineer Basildon 3-Month Contract Paying up to £70p/h (Inside IR35) Please note - due to the nature of the work, you will need to hold or be eligible to obtain a high level of UK Security clearance – please only apply if suitable Key Responsibilities: - C++ software development - Development of new applications to meet user expectations and within formal constraints -...

Job Title: Full-Stack Developer (Asset & Carbon Monitoring Software) Salary: £55,000–£80,000 (depending on experience) Location: Fully remote (UK) You know that decarbonisation isn’t a slogan - it’s a systems problem. If the data’s wrong, if the assets aren’t understood, if the platform can’t scale, then carbon reduction becomes guesswork. This role is for a Full-Stack Developer who wants...

Software Engineer Fully Remote | Permanent | Competitive Salary + Benefits Harrington Starr has partnered with a leading Global Payments Technology company who are seeking to hire a Software Engineer to join their growing engineering team. This is an exciting opportunity to work on scalable, resilient systems while contributing to real-world solutions in the financial technology space. Key...