Software Development Engineer in Test (SDET)

LEGO Digital Play; Greater London; On-site; GBP 65,000 - 90,000; Full time

Job summary

LEGO Digital Play in London HQ is seeking a Software Development Engineer in Test to build test automation frameworks for our SDKs. This newly created role reports to the Lead Engineer, Development Platform, and is based in our London HQ.

We are looking for someone who can develop and run unit, integration, contract, end-to-end and performance tests, and who can apply AI-assisted testing while maintaining robust CI/CD pipelines.

Qualifications

• Strong hands-on software engineering experience; treat test automation as software engineering.
• Proven experience designing and building test automation frameworks from the ground up.
• Proficiency in modern testing approaches: test pyramid, shift-left, contract testing, risk-based design.
• Hands-on experience building and maintaining CI/CD pipelines and integrating automated testing.
• Demonstrated experience using AI tools in testing or engineering workflows.
• Strong debugging and troubleshooting skills across platforms, versions and configurations.
• Fluency in languages used for test automation (C#, Python, TypeScript, Java).
• Excellent communication; explain quality trade-offs clearly to engineers.
• Sound judgement and comfort with ambiguity; define testing strategy where none exists.
• Awareness of safety, privacy, IP, compliance obligations in test coverage.
• Experience testing SDKs
• Experience with Unity or game engines testing
• Performance, load, reliability testing at scale
• Security testing in pipelines
• Evaluating/testing tools or vendors
• Compliance requirements for children's data
• Early-stage quality practice establishment

Responsibilities

• Design and maintain test automation frameworks for the platform's SDKs, APIs, libraries and services.
• Develop and run unit, integration, contract, end-to-end and performance tests with meaningful coverage.
• Build and own CI/CD test pipelines with fast, deterministic quality gates.
• Apply AI-assisted testing to generate and triage tests.
• Diagnose failures across versions, platforms and configs to reduce instability.
• Establish reliability and observable metrics for test estates.
• Collaborate with SDK and platform engineers to bake testing into designs.
• Uphold safety, privacy, IP obligations in test design.

Skills

Hands-on software engineering

Test automation frameworks

Modern testing approaches

CI/CD pipelines

AI-assisted testing

Debugging across platforms

Programming languages

Communication

Testing strategy under ambiguity

Safety and compliance awareness

SDK testing experience

Unity/game engines testing

Performance and reliability testing

Security testing in pipelines

Tools/vendor evaluation

Compliance for children's data

Quality practices in early-stage setup

Job description

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