Mid-Level Software Engineer

Addition Solutions Ltd; Leeds; Hybrid; GBP 38,000 - 43,000; Full time

Benefits offered by this job

25 days annual leave

Pension scheme

Personal development budget

Regular salary reviews

Hybrid working

AI-enabled development exposure

Social events

Job summary

Addition Solutions Ltd is seeking a Mid-Level Software Engineer in Leeds to join a growing Cyber Security SaaS business. You will split time 60% backend (.NET) and 40% frontend (React), building features for a cloud-based platform and using AI-assisted development tools to improve efficiency.

We’re looking for a candidate with 2+ years in software engineering, experience in .NET and React, and familiarity with AWS and relational databases. Hybrid work and a competitive salary are offered.

Qualifications

• Minimum two years of software engineering experience across backend and frontend.
• Commercial experience with .NET, backend services or APIs.
• Experience with React and full stack contributions.
• AWS or another cloud environment exposure; strong AWS advantage.
• Experience with relational databases such as PostgreSQL or SQL Server.
• Experience developing SaaS products within a team environment.
• Solid understanding of Agile development and SDLC.
• Interest in AI-assisted software development and openness to new tools.

Responsibilities

• Develop new product features and improve existing functionality across the SaaS platform.
• Build scalable APIs, backend services and cloud-based solutions with .NET.
• Contribute to frontend development using React.
• Work with PostgreSQL, SQL Server and AWS cloud infrastructure.
• Support full software development lifecycle from design to deployment.

Skills

Backend .NET

React

AWS

SQL

Agile

AI interest

Education

Computer Science degree (nice to have)

Tools

PostgreSQL

Microsoft SQL Server

AWS

Claude AI

REST APIs

Job description

Mid-Level Software Engineer

Permanent | £38,000–£43,000 per annum
Location: Leeds – Hybrid (typically 2 days per week in the office)
Industry: SaaS / Cyber Security

We’re partnering with a growing Cyber Security SaaS business that is investing heavily in its in-house engineering capability and the next stage of its product development.

This is an excellent opportunity for a Mid-Level Software Engineer to work across a modern, cloud-based platform, building new features, improving existing functionality and using AI-assisted development tools to create more efficient ways of working.

The Opportunity

As a Mid-Level Software Engineer, you’ll work across a full-stack environment, with approximately 60% of your focus on backend .NET development and 40% on frontend development using React.

You’ll contribute throughout the development lifecycle, from solution design and coding through to deployment and operations. Working alongside experienced engineers, product specialists and wider business teams, you’ll help turn customer requirements into practical, scalable technical solutions.

This is a varied role offering a balance of new product development and improvements to an established SaaS platform, with genuine scope to influence engineering processes as the internal team continues to grow.

Key Responsibilities

You’ll play an important role in developing and strengthening the platform by:

• Building new product features and improving existing functionality across the SaaS platform.
• Developing scalable APIs, backend services and cloud-based solutions using modern versions of .NET.
• Contributing to frontend development using React.
• Working with PostgreSQL, Microsoft SQL Server and cloud infrastructure within an AWS environment.
• Supporting the complete software development lifecycle, including solution design, coding, testing, deployment and operations.
• Collaborating with other engineers through pair programming, code reviews and technical discussions.
• Working closely with product and wider business teams to translate customer and commercial requirements into effective technical solutions.
• Helping improve engineering processes, reduce maintenance overhead and increase the team’s focus on new product development.
• Using AI-assisted development tools, including Claude, to improve development efficiency and make the codebase easier to maintain.
• Contributing to the continued development of the organisation’s growing in-house engineering capability.

About You

You’ll have a minimum of two years’ experience in software engineering and be comfortable contributing across both backend and frontend development.

You will also have:

• Commercial experience with .NET, ideally developing backend services or APIs.
• Experience with React and a willingness to contribute across the full technology stack.
• Exposure to AWS or another major cloud environment, with strong AWS experience considered a significant advantage.
• Experience working with relational databases such as PostgreSQL or Microsoft SQL Server.
• Previous experience developing SaaS products as part of a collaborative engineering team.
• A good understanding of Agile development practices and the wider software development lifecycle.
• Experience balancing new feature development with improvements to an existing platform.
• An interest in AI-assisted software development and an openness to adopting new tools and technologies.
• Strong problem-solving, communication and collaboration skills.
• A Computer Science degree would be beneficial but is not essential.

Why Apply?

This is a fantastic opportunity to join a growing engineering function where you’ll have the support of experienced colleagues while taking on increasing responsibility and developing your technical capabilities.

In return, you’ll benefit from:

• A salary of £38,000–£43,000 per annum.
• Hybrid working, typically requiring around two days per week in the central Leeds office.
• 25 days’ annual leave.
• A pension scheme.
• A personal development budget for relevant courses, certifications and conferences.
• Regular salary reviews.
• The opportunity to work with modern versions of .NET and a cloud-first AWS environment.
• Exposure to AI-enabled development and the freedom to explore tools that improve how software is built.
• Genuine scope to develop your skills and influence a growing internal engineering function.
• Regular company social events.

We are an equal opportunity employer and value diversity at our company. We do not discriminate on the basis of race, religion, colour, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status.

By applying you are confirming you are happy to be added to the Addition Solutions mailing list regarding future suitable positions. You can opt out of this at any time simply by contacting one of our consultants.