Senior Software Development Engineer in Test - SDET (Belfast, Northern Ireland)

Job Title: Senior Software Development Engineer in Test (SDET)
Location: Belfast, Northern Ireland
Work Arrangement: Hybrid (In-Office)
We are seeking a dynamic Senior Software Development Engineer in Test (SDET) who will serve as a catalyst for quality and innovation within our engineering organization. In this senior role, you will be instrumental in building and maintaining our automated testing infrastructure, enabling rapid feedback cycles and ensuring the delivery of high-quality software at speed. Your responsibilities will extend beyond traditional testing boundaries; you will act as a technical leader who advocates for quality throughout the entire software development lifecycle. From influencing architectural decisions to implementing robust testing frameworks, you’ll collaborate with development teams to create efficient, maintainable, and scalable test automation solutions. If you are passionate about quality engineering and view yourself as a strategic partner who can help embed quality into the development process from the ground up—rather than just testing it at the end—we want you on our team. You will have the opportunity to drive testing best practices, mentor others in test automation, and play a crucial role in our continuous delivery pipeline. You will be expected to design test strategies, lead test architecture, and drive measurable improvements in our product quality.
About Us: Recently ranked #259 on the Inc. 5000 fastest growing companies in the United States, Biller Genie is an award-winning B2B SaaS platform that is entering the Belfast market with ambitious plans to scale our team rapidly, with over 100 hires planned through 2026. 
Primary Job Responsibilities:

• Test Architecture: Design and implement scalable test automation frameworks that enable rapid feedback and continuous testing
• Quality Engineering: Partner with development teams to build quality into the development process through test automation, code reviews, and best practices
• Innovation: Research and implement new testing tools and methodologies to improve our testing efficiency and coverage
• Continuous Improvement: Lead initiatives to enhance our testing infrastructure, practices, and metrics to drive quality improvements
• Technical Leadership: Mentor team members in test automation best practices and quality engineering principles
• Perform other duties required by Management

Essential Criteria:

• BSc or MSc in Computer Science, Software Engineering or related field
• Minimum of 5 years of software testing experience in SaaS environments
• Strong proficiency in at least one programming language (e.g. C#, Python etc.)
• Extensive experience with test automation frameworks and tools (e.g. SpecFlow, Moq, NUnit)
• Experience with API testing tools (e.g. Postman, RESTSharp)
• Strong attention to detail and work ethic
• Analytical and problem-solving skills
• Excellent communication (both written and verbal) and interpersonal skills
• Proficient with Git and related workflows
• Familiarity with CI/CD pipelines and tools
• Ability to work effectively with cross-functional teams
• Legal right to work in the UK

Desirable Criteria:

• Experience in Performance testing frameworks
• Experience in Financial services industry
• Familiarity with LEAN software development practices
• Experience with AWS, Azure of GCP
• Knowledge of Security testing principles and tools
• ISTQB Advanced level or relevant technical certifications
• Experience with test data generation and management

What We Offer:

• Private health insurance
• Group life death benefit
• Auto-enrollment pension with employer contributions matched to 5%
• 25 days holiday per year
• 10 statutory/bank holidays per year
• Opportunities for professional growth and development
• A collaborative and innovative work environment

Our Mission: To provide an automated A/R platform that seamlessly integrates existing business processes for the SMB market.
Our Core Values:
Get Shit Done Right - We work hard and ensure tasks are completed correctly and on time, every time.
Own it - We are subject matter experts who know what we know, and we are confident enough to speak up when we see something wrong.
Catch Up - We are high performers and love a fast-paced environment.
Believe in the Genie - We are passionate about where we are going as a team, and we show we care.
Class Shines - We are articulate professionals who carry ourselves well and speak with purpose.
Please note we are unable to offer visa sponsorship.