Senior Dotnet Developer

Senior Application Services Developer

Brennan. Where true performance thrives.

At Brennan, we believe that how technology is delivered is every bit as important as what the technology is. We focus on creating real and relevant value for customers with solutions that fit their specific needs and always reflect their true interests. It’s a claim backed by our True Performance System – a way of working engineered to get us closer, and deliver better, for our customers and their actual experience of technology.

Why join Brennan

True performance for our customers starts with a true belief in our people.

It’s why we’ve structured our business to help our teams, and their talents, shine bright. It's why we’ve created a workplace where people of all backgrounds, beliefs and experiences are welcomed and empowered. And it’s why we’ve built an organization where real innovation makes a genuine impact and generates true rewards for our team members.

True rewards

In addition to competitive remuneration, Brennan offers extensive benefits, including :

Training and certification bonuses

Culture Awards that recognize excellence

Brennan Daredevils – our annual, all-expenses paid trip awarded to our top performers and outstanding contributors

Vibrant, fun social activities.

An environment that embraces learning and development

The Role

The Senior Application Services Developer plays a key role in supporting and enhancing our customers’ applications as part of our Managed Application Services team. You will be responsible for maintaining strong relationships with clients through regular health checks, performance reviews, and proactive engagement to ensure their applications remain secure, reliable, and effective.

This role combines hands-on technical support, development, and problem-solving with leadership and mentoring responsibilities within the team. You will provide expert-level troubleshooting, design and implement solutions, estimate work effort, and produce technical documentation — all while sharing knowledge and guiding junior developers to drive continuous improvement.

Role Responsibilities

Maintain proactive relationships with customers, including conducting monthly application health checks and service review meetings.

Provide Level 3 technical support, investigating and resolving complex issues in line with service level agreements (SLAs).

Perform detailed root cause analysis and problem management to prevent recurring issues.

Collaborate with customers and internal teams to gather requirements, scope solutions, and provide accurate effort estimates.

Review peer code, ensuring adherence to quality standards, best practices, and security guidelines.

Mentor and support other developers by sharing expertise, encouraging best practices, and promoting a collaborative team environment.

Stay up to date with emerging technologies and maintain relevant industry certifications.

Perform any other tasks aligned with your role or in support of your team as advised by your leader.

Key Competencies and Qualifications required

Minimum 6 years of experience in IT application development or support.

Minimum 5 years of experience in .NET development.

Strong analytical, troubleshooting, and problem-solving skills.

Excellent verbal and written communication skills, including documentation and client engagement.

Proven ability to work effectively within and across teams.

Experience with Azure DevOps, version control systems, and ticket management tools.

Experience with Azure services, particularly Logic Apps and Function Apps.

Front-end development experience with Angular and / or React.

Experience with SQL Server and database design.

Experience with web technologies such as HTML, CSS, and JavaScript.

Familiarity with ITIL or Managed Services environments.

Brennan is an equal opportunity employer.