Senior Software Development Engineer in Test (SDET) - B2B SaaS | Hybrid in London

B2B SaaS | Hybrid – 2-3 days office | UK

Role overview

Accessible rail travel depends on systems that work reliably in live environments. Our Passenger Assistance platform turns passenger assistance requests into coordinated action inside live rail operations. We’re looking for a Senior Software Development Engineer in Test (SDET) to act as a true development partner, embedded within our feature teams rather than operating as a traditional QA resource. You’ll write code, collaborate closely with engineers, and ensure quality is built into features from the start through meaningful, business-aligned automated testing - not just test case execution or edge-case overengineering.

Strategic Context

Transreport exists to remove structural barriers in rail travel. Our vision is that everyone has access to travel everywhere. As a Series A technology company and recipient of a King’s Award, we operate across the UK, Japan and the EU, delivering award-winning accessibility and safety platforms that have supported over 10 million assistance requests for more than 1 million users. As our platform scales across markets and grows in complexity, we are hiring a Senior SDET to embed quality engineering into feature development and strengthen automated test coverage across our systems.

Outcomes & Impact

• Within 6 months, you will:
• Establish strong collaboration patterns with backend and mobile engineers
• Improve automated test coverage across core business workflows
• Strengthen CI/CD integration for automated testing
• Introduce clearer quality standards within feature development

• Within 12 months, you will:
• Act as the go-to quality engineering partner across multiple product areas
• Reduce regression issues through robust, business-focused automation
• Influence architectural decisions to improve system testability
• Help scale automated testing practices as the platform grows

Responsibilities

• Collaborate with developers during feature development to design and implement automated tests that validate core business functionality
• Own and improve unit and integration testing across services and platforms
• Build and maintain scalable automated test suites integrated into CI/CD pipelines
• Contribute to code reviews and architecture discussions to improve testability and quality
• Ensure testing focuses on real-world business scenarios rather than exhaustive edge cases
• Partner with Ruby backend and iOS/Android teams to maintain consistent quality standards

Technical Environment

• Backend: Ruby / RSpec
• Cross-functional collaboration with iOS and Android engineers
• Focus on automated testing (not manual QA)

Requirements

Must Haves

• Strong experience with test automation frameworks and tools (preferably in Ruby / RSpec)
• Solid understanding of the SDLC in a coding-heavy environment
• Ability to write and review code as part of quality engineering
• Experience integrating automated tests into CI/CD pipelines
• Comfortable working closely with developers during feature development
• Ability to align automated testing with business requirements rather than focusing on manual QA

Nice to Haves

• Experience working with mobile ecosystems (iOS / Android)
• Experience in Ruby-based backend environments

Benefits

• Private healthcare after your probation (including children)
• Hybrid working model
• 25 days holiday
• Volunteering Leave
• Free flu jab for you and your family

Culture & Operating Principles

We value:

• Ownership over hierarchy
• Clarity over bureaucracy
• Impact over job titles

We operate with high autonomy and high accountability. People are expected to raise risks early, communicate clearly, and take responsibility for outcomes.

Interview Roadmap

1. Screening Call (30 mins) – Recruiter alignment
2. Technical Exercise – Automated testing approach & coding discussion
3. Deep Dive Interview – Quality engineering, architecture, and collaboration with Engineering & Product
4. Final Interview – Culture and leadership alignment

We aim to complete the process within 4 weeks.

Guaranteed Interview Scheme

We’re a Disability Confident employer and we welcome applications from disabled candidates. If you need any adjustments at any stage of the recruitment process, please tell us what would help - we’ll work with you to make the process as accessible as possible. We also offer a Guaranteed Interview Scheme (GIS) for candidates who consider themselves to have a disability as defined under the Equality Act 2010. If you indicate this option in your application and your application demonstrates that you meet the essential criteria for the role, you’ll be invited to interview or assessment. Choosing GIS doesn’t guarantee a job offer. If you have any questions, please get in touch.