[Hiring] Senior SDET - Framework Team @Semble

Role Description

The Senior SDET, Frameworks role will lead the evolution of Semble’s test automation capability and help make quality a shared engineering discipline. You will:

• Lead the transformation towards a Quality Agent System, using AI agents and deterministic automation to continuously identify coverage gaps, generate and maintain tests, detect flaky tests, support exploratory testing, and surface reproducible defects.
• Design safe, maintainable agent workflows with clear responsibilities, isolated execution, human review, and appropriate controls. Agents should assist engineers and SDETs, not replace human judgement or merge their own changes.
• Establish the foundations required for this system, including a stable Playwright framework, reliable CI integration, ephemeral test environments, test data management, quality observability, and structured test knowledge.
• Set up meaningful quality gates in CI and PR workflows, including coverage validation, framework conventions, high-risk code checks, and actionable failure reporting.
• Rationalise our overcrowded E2E suite by identifying tests that belong at unit, API, or integration level, keeping E2E focused on critical user journeys.
• Build and maintain a cross-layer coverage map and risk-based defect view, helping teams understand where quality gaps exist and where automation investment will have the greatest impact.
• Expand test coverage and surface quality gaps earlier in the development lifecycle, including through test scenario generation, mutation testing, and AI-assisted exploratory testing.
• Conduct proof-of-concepts for non-functional testing, including performance, accessibility, security, and reliability testing.
• Contribute to company-wide quality strategy, tooling decisions, quality metrics, and shift-left adoption alongside the wider SDET and Engineering teams.
• Coach engineers and SDETs on effective test design, the testing pyramid, Playwright, and contributing to the shared framework.

Qualifications

• 5+ years of professional experience as SDET or Test Automation Engineer.
• A strong track record of designing, building, and evolving automation frameworks that are reliable, maintainable, and easy for engineers to adopt.
• Hands-on experience building AI-augmented or agentic quality workflows, not only using tools such as Cursor or Claude to generate test code.
• A pragmatic approach to AI adoption, with awareness of data privacy, security, clinical safety, cost, and false-positive risks.
• Strong commercial experience with TypeScript-based automation frameworks. Playwright experience is highly desirable.
• Experience with test coverage strategy and applying the testing pyramid to reduce unnecessary E2E testing.
• Experience with writing unit, component, API, and integration tests.
• Experience with performance testing tools, such as k6, is desirable.
• Knowledge of non-functional testing, including performance, accessibility, security, and reliability.
• Exposure to DevOps tools and cloud infrastructure, including Jenkins, Bitbucket, Datadog, and AWS.
• Strong written and verbal communication skills, with the confidence to represent the SDET function, challenge assumptions, and defend quality in release discussions.

Benefits

• The great feeling coming with knowing you do something that matters: shaping the future of healthcare!
• £65-75k package (based on your experience and the value you can bring).
• Autonomy and ownership – we’ll set the vision and share the context, then we trust you to run with things – that’s the reason we hire you!
• 36 days off: 25 holidays + bank holidays + 3 extra days (birthday and ‘feel good’ days) - that we will expect you to actually take so you can recharge and rest.
• Private Health Insurance – covering physical and mental health, as well as dental and optical!
• Get the tech you need - You will get the latest MacBook (unless you prefer Windows) and take your pick across a wide range of equipment to set up your home office ergonomically.
• Work alongside an inspiring team – our two founders have started Semble after a successful startup exit, and your future colleagues are all knowledgeable and innovators in their field.
• Fantastic office space in Central London, right outside Monument - with a roof terrace, weekly animations, loads of natural light, and cute doggies!
• The usual free bits coming with nice offices (barista coffee, tea, fruits, happy hours and activities).