Senior Software Development Engineer in Test (Back-End) in Belfast

About us @Symphony
We have spent the last 10 years building a communication and markets technology company, powered by interconnected platforms: messaging, voice, directory and analytics. Over 1000 institutions use our modular technology built for global finance. Security is in our DNA with uncompromising data protection, end-to-end encryption and resilient architecture, all created on a foundation of trust with our customers.

But that was only chapter one. We are now building on our purpose‐built network, expanding AI‐powered, real‐time collaboration, redefining flexibility with fully cloud‐native software with our trader voice product, and rethinking the industry's approach to identity verification, connection and intelligence. The opportunity and our ambition are huge. But we need passionate, dedicated individuals to get there. At Symphony we work hard and fast. Our unique blend of technology and financial services makes it an environment you won't get elsewhere.

Role Description
We are looking for a highly skilled and motivated Senior SDET (Software Development Engineer in Test), Backend to take a lead role in ensuring the quality and reliability of our backend components supporting both mobile and desktop clients. In this role, you will design, develop, and maintain scalable test automation frameworks, collaborate closely with developers, and drive a shift‐left testing mindset within the engineering teams.

As a technical quality leader, you will bring strong expertise in backend testing, white box testing, and development practices. You will play a key role in supporting the execution of the Backend Test Strategy, coordinating across teams and products, and ensuring the delivery of robust, secure, and performant backend solutions.

If you are passionate about backend quality, automation, and engineering excellence, we would love to hear from you!

Responsibilities

• Take ownership of quality initiatives for backend components supporting mobile and desktop clients.
• Design, implement, and maintain test automation frameworks for backend systems.
• Work closely with developers to enable shift‐left testing practices and embed quality earlier in the development lifecycle.
• Apply strong skills in backend and white box testing to validate APIs, services, and integrations.
• Ensure reliable test execution across Cloud (GCP/AWS), Kubernetes, and Windows 10/11 environments.
• Collaborate across teams and product lines to drive quality alignment and consistency.
• Troubleshoot, debug, and resolve issues in complex backend systems.
• Mentor other SDETs and contribute to continuous improvement of test strategies, processes, and tools.
• Support the execution and evolution of the Backend Test Strategy.

Required Qualifications

• Strong programming skills in C# and TypeScript (nice to have).
• Proven experience with backend testing and automation frameworks.
• Hands‐on experience in white‐box testing of APIs, services, WebSocket connections, and backend systems.
• Strong understanding of WebSocket protocols, WebRTC, and practical experience testing WebSocket‐based services.
• Knowledge of cloud environments (GCP/AWS) and containerised deployments using Kubernetes.
• Familiarity with Windows 10/11 environments.
• Experience with CI/CD pipelines, Git, and backend testing tools.
• Strong understanding of backend development practices and modern testing methodologies.

• Proven leadership in driving backend quality initiatives.
• Excellent communication, collaboration, and coordination skills.
• Strong analytical and problem‐solving skills with attention to detail.
• Ability to thrive in a fast‐paced, cross‐functional environment.
• Proactive, self‐motivated, and passionate about backend quality and automation.

Education & Experience
Bachelor's or Master's degree in Computer Science, Software Engineering, or related field (or equivalent practical experience). 5+ years of experience in software testing or SDET roles, with a strong focus on backend systems. At least 2+ years in a senior or lead capacity, driving quality initiatives at scale.

Compensation
Competitive salary. Bonus Plan. Benefits and Perks vary based on location.

We are an equal opportunity employer and value diversity at our company. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status. We will ensure that individuals with disabilities are provided reasonable accommodation to participate in the job application or interview process, to perform essential job functions, and to receive other benefits and privileges of employment.

Seniority level: Mid‐Senior level
Employment type: Full‐time
Job function: Engineering and Information Technology.