Senior Software Development Engineer in Test

billergenie; Belfast City District; Hybrid; GBP 65,000 - 95,000; Full time

Benefits offered by this job

Private health insurance

Group life

Pension with 5% matched

25 days holiday

10 bank holidays

Professional growth

Collaborative environment

Job summary

billergenie in Belfast, Northern Ireland, is seeking a Senior Software Development Engineer in Test (SDET) to elevate quality across our engineering teams. You will design scalable test strategies, build automated testing infrastructure, and mentor others to embed quality from the ground up in a fintech context.

You will lead with expertise in test automation, API and UI testing, and embrace AI tooling to accelerate feedback and delivery.

Qualifications

• Degree in Computer Science/Software Engineering or equivalent
• Minimum 5 years of software testing experience in SaaS environments
• Proficiency in at least one OO language (C#, Java, or Python)
• Experience with test automation frameworks (NUnit, xUnit, Moq, SpecFlow/Reqnroll)
• Experience with API testing tools (Postman, RestSharp)
• Experience with UI automation (Playwright, Selenium)
• Experience with AI and agentic engineering processes
• SQL knowledge and database testing
• Familiarity with CI/CD pipelines
• Experience with Azure/AWS/GCP
• Git proficiency
• Strong communication and teamwork
• Legal right to work in the UK

Responsibilities

• Test Architecture: Design and implement scalable test automation frameworks
• Quality Engineering: Partner with development teams to build quality into the development process
• Innovation: Research and implement new testing tools and methodologies, including AI
• Continuous Improvement: Lead initiatives to enhance testing infrastructure and metrics
• Technical Leadership: Mentor team members in test automation best practices
• Perform other duties required by Management

Skills

Test automation

API testing

UI automation

AI tooling

CI/CD

Cloud basics

Git workflows

Cross-team collaboration

Communication skills

C#/Java/Python

Education

BSc/MSc in CS/SE

Tools

NUnit

xUnit

Moq

SpecFlow/Reqnroll

Postman

RestSharp

Playwright

Selenium

Azure

AWS

GCP

Git

Job description

Job Title: Senior Software Development Engineer in Test (SDET)

Location: Belfast, Northern Ireland

Work Arrangement: Hybrid

Position Overview

We are seeking an experienced Senior Software Development Engineer in Test (SDET) to act as a catalyst for quality across our engineering organisation. You will be a first‑class engineer who builds & maintains our automated testing infrastructure, enabling rapid feedback cycles and the delivery of high‑quality software at speed. This is a technical leadership role: you will advocate for quality throughout the software development lifecycle, design test strategies, influence our test architecture, mentor others in test automation, and partner with engineering teams to build quality in from the ground up rather than test it at the end.

We are an AI‑enabled engineering team, and we believe the future is about empowering engineers with the latest tools, building through custom skills, agents, and harnesses, and we are looking for people who embrace AI, are excited about the future, and want to shape the way we embed AI tooling throughout our developer experience.

If you are passionate about quality engineering, comfortable using AI tooling to work faster and smarter, and want to shape testing practice in a fast‑paced fintech environment, we want you on our team.

About Us

Recently ranked #482 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 2028.

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, including AI and agentic engineering approaches, 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 OR equivalent commercial experience
• Minimum 5 years of software testing experience in SaaS environments
• Strong proficiency in at least one object‑oriented programming language, ideally C#, though strong OO fundamentals in Java, Python or a similar language are equally welcome
• Extensive hands‑on experience with test automation frameworks and tools (e.g. NUnit, xUnit, Moq, SpecFlow/Reqnroll, or the equivalents in your language of choice)
• Experience with API testing tools and techniques (e.g. Postman, RestSharp)
• Experience with UI/browser automation (e.g. Playwright, Selenium)
• Practical experience working with AI and agentic engineering processes
• Working knowledge of SQL and database testing
• Familiarity with CI/CD pipelines and tools
• Experience of cloud technologies such as Azure, AWS, GCP
• Proficient with Git and related workflows
• Strong attention to detail and work ethic
• Strong analytical and problem-solving skills
• Excellent communication (both written and verbal) and interpersonal skills
• Ability to work effectively with cross‑functional teams
• Legal right to work in the UK

Desirable Criteria

• Proficient with Claude or Claude Code
• Experience with performance testing frameworks and tools (e.g. k6, JMeter, NBomber)
• Knowledge of security testing principles and tools
• Experience with test data generation and management
• Experience of LEAN software development practices
• Experience with Azure Functions and Queues
• ISTQB Advanced Level or relevant technical certifications
• Experience in the Financial services industry
• Experience mentoring engineers or leading a test/QA function

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.

Pleasenote we are unable to offer visa sponsorship.