Software Development Engineer in Test (SDET)

Software Development Engineer in Test (SDET) LEGO Digital Play will bring the LEGO brand into digital entertainment in new, innovative, and wholly-owned ways. Our mission is to ensure the LEGO Brand remains as powerfully a part of children’s lives in the coming decades as it has ever been. We aim to reach every kid on the planet, their parents, and adult fans of LEGO—and provide them with meaningful, magical, and playful new experiences. Central Technology is the engineering heart of LEGO Digital Play, a venture within the LEGO ecosystem dedicated to pioneering creative and joyful digital experiences. Our teams build the foundational platforms, tools, and capabilities that power LEGO's digital future. We work at the intersection of play, applied AI, and developer tooling to bring the LEGO brand to a new generation of digital builders. It's a rare opportunity to shape something from the ground up within one of the world's most loved brands. We are at the earliest phases of this new company, offering a unique opportunity to build a new entity for the world's most beloved and trusted brand. Our culture is open, collaborative, intellectually rigorous, and creatively vibrant. Role Summary The Central Technology team is the engineering heart of LEGO Digital Play, a venture within the LEGO ecosystem dedicated to pioneering creative and joyful digital experiences. Our teams build the foundational platforms, tools, and capabilities that power LEGO's digital future. We work at the intersection of play, applied AI, and developer tooling to bring the LEGO brand to a new generation of digital builders. It's a rare opportunity to shape something from the ground up within one of the world's most loved brands. We are looking for a Software Development Engineer in Test to build test automation frameworks for our SDK’s. This is a newly created role reporting to the Lead Engineer, Development Platform based in our London HQ. Key Responsibilities Design, build and maintain test automation frameworks and harnesses for the platform's SDKs, APIs, libraries and services, treating test code with the same rigour as production code Develop and run tests across the pyramid: unit, integration, contract, end-to-end and performance; ensure coverage is meaningful and repeatable Build and own the continuous integration and continuous delivery test pipelines; make quality gates fast, deterministic and reliable so teams can ship with confidence Apply AI-assisted testing tools to generate, maintain and triage tests, and set clear guidance on where AI accelerates the work and where human review is required Diagnose failures to root cause across engine versions, platforms and configurations; drive down instability and keep the suite trusted Establish reliability and observability for the test estate: clear reporting, actionable signals and metrics on quality, coverage and pipeline health Partner with SDK and platform engineers to make testing a first class principle (“shift left testing”), embed testability into designs and feed defects back as clear, prioritised input Uphold the platform's safety, brand integrity, privacy and IP obligations in test design, including validation of compliance-sensitive behaviour Required Qualifications Strong hands-on software engineering experience; you write clean, maintainable code and treat test automation as software engineering Proven experience designing and building test automation frameworks from the ground up, not only writing tests within an existing one Proficiency in modern testing approaches: the test pyramid, shift-left testing, contract testing, and risk-based test design Hands-on experience building and maintaining CI/CD pipelines and integrating automated testing into them Demonstrated experience using AI tools in a testing or engineering workflow, with sound judgement about their strengths and limits Strong debugging and troubleshooting skills across platforms, versions and configurations, with a track record of driving down flaky tests Fluency in one or more languages commonly used for test automation, such as C#, Python, TypeScript or Java Excellent communication; able to work directly with engineers, explain quality trade-offs clearly and stay credible with the teams you support Sound judgement and comfort with ambiguity; able to define a testing strategy where none yet exists Awareness of safety, privacy, IP and compliance obligations and how they translate into test coverage Preferred Qualifications Experience testing SDKs, developer libraries or platform APIs consumed by other engineers Experience with game development or game engines such as Unity, including automated testing in a live project Performance, load and reliability testing experience at scale Experience with security testing or building security checks into a pipeline Experience evaluating and selecting testing tools or vendors Experience supporting a platform with meaningful compliance requirements, particularly those involving children's data Early-stage or founding experience establishing quality practices for a new platform Department Central Technology Locations LEGO Digital Play London Office Remote status Hybrid