Principal Agentic SDET Engineer

Principal Agentic Software Development Engineer in Test Full Stack

We are looking for a full-stack Principal Software Development Engineer in Test to join us in validating our security products and associated platforms. The successful candidate will be a self-starter with an automate-first and AI-first mindset ready to validate complex test environments with many touch points across UI API services cloud platforms integrations data and third-party systems.

This role requires someone who can combine deep hands-on engineering capability with technical leadership using modern automation CI/CD observability and AI-enabled engineering practices to improve quality speed reliability and release confidence.

A positive attitude strong ownership mindset and willingness to learn coach and share knowledge are essential.

Mimecast provides cyber security that helps thousands of organizations worldwide make email and messaging safer restore trust and bolster cyber resilience. We help organizations stand strong in the face of cyberattacks human error and technical failure.

At Mimecast Principal Software Development Engineers in Test are responsible for:

• Providing technical leadership and coaching/mentoring other engineers on the team to deliver testing for large projects and/or ongoing product efforts.
• Acting as a senior technical voice for Quality Engineering across product platform architecture development DevOps and security teams.
• Taking initiative to drive continuous improvement through monitoring tooling automation process improvements and engineering best practices.
• Bringing an AI-first mindset to quality engineering by identifying practical ways to use AI to improve test design test automation code review defect analysis test coverage documentation and engineering productivity.
• Standardising the agents to build QE process as a QE Engine.
• Helping teams adopt AI-enabled engineering practices safely and effectively ensuring AI is used to accelerate delivery while maintaining quality security and engineering discipline.
• Building out test plans to cover new areas of functionality ensuring all necessary functional and non-functional testing is performed.
• Contributing to the planning estimation and refinement of stories epics and design changes as part of an Agile Scrum team.
• Refining acceptance criteria into testable units and converting those into automated tests that execute efficiently and reliably.
• Using AI-assisted tools to accelerate acceptance criteria analysis test scenario generation edge-case discovery and automation development.
• Integrating automated tests with CI/CD pipelines and ensuring successful automation as part of the standard build and release process.
• Driving continuous testing practices across the delivery lifecycle ensuring fast reliable feedback to engineering teams.
• Reporting reproducing and helping development resolve defects with emphasis on troubleshooting root cause analysis and prevention of similar issues in the future.
• Using logs code telemetry dashboards traces and AI-assisted analysis techniques to investigate defects and identify systemic quality issues.
• Contributing to design and code reviews for product and test code.
• Coaching engineers on testability automation design coding standards maintainability and quality-focused engineering practices.
• Promoting quality as a shared engineering responsibility not just a downstream testing activity.

Required Skills / Experience:

• 10 years of experience as a Software Development Engineer in Test (or similar role)
• Significant experience in building AI QE process recently.
• Engineering / Computer science degree or equivalent experience
• Extensive experience test planning and breaking down stories/requirements into testable units
• 6 years of significant test automation work validating both back-end and front-end interfaces in at least one high-level object-oriented language including:
  • Extensive experience automating business logic in the services layer (RESTful API SDK or CLI as appropriate)
    • Proficiency in validating contract functionality correctness and performance of REST API endpoints
    • Familiarity with BDD tools like Cucumber Jasmine or equivalent
    • Clear understanding of how to manage risk through negative testing boundary/limits testing load/soak testing and other test aspects as appropriate including system integration performance/scale security
    • Solid object-oriented programming skills and experience automating in Java or similar
  • Substantial experience in validation of UI-functionality and rendering End-to-End testing and UAT scenarios
    • Extensive knowledge of Cypress with demonstratable experience in Protractor / Selenium
    • Knowledge of Web Browsers HTML CSS JavaScript TypeScript Angular JSON XML integration with APIs web servers
    • Great knowledge of testing design patterns - for example the Page Object Model
• 4 years of experience as a technical leader of test projects and test teams
• Top notch coding skills provision at conducting effective code reviews and coaching the team to raise their coding proficiency
• Extensive experience with CI/CD and Continuous Delivery model using Jenkins (or similar)
• Working knowledge of public cloud especially AWS and how to execute testing in an efficient cost-effective manner in that environment
• Solid DB understanding (types schemas SQL queries basic operations) and ability to incorporate database-side validation into automated tests
• Experience with multithreading concurrency SaaS and multi-tenant architectures
• Proven ability to integrate with and automate using third party APIs (e.g. Google Microsoft Amazon etc)
• Experience with observability monitoring synthetic testing chaos engineering disaster recovery testing or production-readiness validation.
• Experience using AI tools such as GitHub Copilot Cursor ChatGPT Enterprise Atlassian Intelligence/Rovo or similar platforms to improve engineering productivity.
• Experience creating or improving quality dashboards shift-left metrics escaped defect analysis automation reliability metrics or engineering productivity insights.
• Experience with contract testing service virtualisation test data management or intelligent regression selection.
• Some working knowledge of Microsoft Exchange Office365 Azure Active Directory and Windows Server

AI-First Engineering Expectations

The successful candidate will be expected to bring an AI-first but engineering-led mindset. This means being able to identify where AI can genuinely improve engineering outcomes while maintaining strong technical judgement quality standards and security awareness. This includes:

• Using AI to accelerate repetitive or analysis-heavy engineering tasks.
• Applying AI to improve test design scenario coverage code quality defect diagnosis and documentation.
• Helping teams move from ad hoc AI usage to repeatable trusted engineering workflows.
• Coaching engineers on where AI is useful where it is risky and how to validate AI-generated output.
• Measuring the impact of AI adoption through productivity quality reliability and speed-of-feedback improvements.
• Ensuring AI usage supports secure responsible and compliant engineering practices.

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Belonging at Mimecast

Cybersecurity is a community effort. Thats why were committed to building an inclusive diverse community that celebrates and welcomes everyone unless theyre a cybercriminal of course.

Were proud to be an Equal Opportunity and Affirmative Action Employer and wed encourage you to join us whatever your background. We particularly welcome applicants from traditionally underrepresented groups.

We consider everyone equally: your race age religion sexual orientation gender identity ability marital status nationality or any other protected characteristic wont affect your application.

Due to certain obligations to our customers an offer of employment will be subject to your successful completion of applicable background checks conducted in accordance with local law.

It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment.