Job Specifications
Principal DATA SDET - Data Framework Architect | Hybrid (London) | Up to £600 p/d Inside IR35
Eligibility: Due to background screening requirements, candidates must hold British Citizenship or Indefinite Leave to Remain (ILR) to be considered
Required Sector Experience: Finance or Investment Management
Must Have Tech Skills: Python, SQL, Databricks or Snowflake (or similar), with Playwright and/or Selenium
Strict Requirements - Please Read Before Applying | Only apply if you meet all of the following:
Advanced data testing expertise - including data migrations, SQL, Python
Hands-on experience with Databricks and/or Snowflake (or similar)
Minimum 4 years’ hands-on experience - not theoretical, not junior
Framework architecture skills - building robust automation from scratch
Strong stakeholder engagement - translating business needs into test strategies
All criteria are non-negotiable. If you don’t tick every box, this isn’t the right fit for you.
Optimal have partnered with a leading financial services organisation is seeking a Principal Software Development Engineer in Test (SDET) to architect and deliver world-class test automation frameworks. This is a strategic and hands-on opportunity for a technical expert in data migration testing, ETL validation, and automation framework design using C# and Python.
You’ll drive the technical direction for automation, working across data, backend, and UI layers - embedding quality at scale across complex, high-trust systems.
Core Focus Areas
Data Validation & Migration Testing
Advanced data validation using SQL, Snowflake, and Databricks
Hands-on testing of data pipelines, ETL processes, and large-scale migrations
Strong understanding of data lineage, reconciliation, and transformation accuracy
Automation Framework Development
Framework architecture from scratch in enterprise-grade ecosystems
SpecFlow, Playwright, Cypress, and Selenium (incl. Recnroll) - UI, API, and end-to-end automation
Full lifecycle automation ownership – design, implementation, and CI/CD integration
Performance & Reliability Testing
Tools: JMeter, k6, Gatling – load, stress, and performance benchmarking across APIs and distributed systems
Establish and maintain performance baselines and regression monitoring
Infrastructure & DevOps Integration
Cloud: AWS, Azure DevOps, GCP – testing in containerised, scalable environments
CI/CD: Seamless integration of automation suites and quality gates into distributed pipelines
Strategic & Architectural Impact
Design and scale robust automation frameworks from scratch
Embed quality engineering principles across microservices, APIs, and event-driven systems
Contribute to architectural decisions influencing reliability, maintainability, and performance
Operate as a technical authority and hands-on engineer, not a passive test lead
Ideal Background
Strong background in data-centric testing and enterprise-scale system validation
Experience within asset management, investment platforms, or financial services environments
Proven ability to lead automation strategy while remaining 80%+ hands-on
Excellent communicator and collaborator, working closely with developers and DevOps teams
Working Model
Hybrid: 2–3 days per week in central London
Collaborative, forward-thinking engineering culture focused on technical excellence and innovation
If this role is of interest and tick all of the above boxes reach out to us at Optimal for a very quick response.
About the Company
At Optimal, recruitment is more than just matching candidates with roles - it's about building lasting relationships and thriving communities.
Our founder, with over 20 years of technical IT recruitment experience, is a passionate advocate for community engagement and the organiser of the first-ever London Ministry of Testing Meetup. Combining technical expertise with a CT-AI certification, they have made Optimal a true recruitment specialist.
Our core expertise lies in Test, Development, and Quality Engineering. Additiona...
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