Senior Architect - Email & Collaboration Security

The Email & Collaboration Security (ECS) product line sits at the intersection of some of the most consequential challenges in enterprise security today: AI-augmented threats, sprawling collaboration surfaces, multi-cloud delivery complexity, and the expectation that detection and response capabilities keep pace with a threat landscape that does not wait. This architecture is not greenfield. It carries two decades of accumulated product decisions, integration contracts, and operational constraints. The right candidate understands why that history matters before proposing how to move beyond it.

The successful candidate will serve as connective tissue across product management, engineering, and the broader Architecture Leadership Team — turning customer and business problems into coherent, deliverable technical direction, and owning the decisions that give ECS engineering teams a stable foundation to move fast with quality.

AI-First Ways of Working

Mimecast is an AI-first engineering organisation. The person in this role is expected to use AI tools as a genuine, daily part of how they work: for design exploration and iteration, documentation, analysis, prototyping, and research synthesis. This means having a real, practised opinion on where AI tooling accelerates quality decisions and where it introduces risk. It also means designing systems that incorporate AI components thoughtfully.

The ECS Domain

• Email threat detection and prevention
• Email security efficacy
• Collaboration security
• DMARC analyzer
• Data platform and observability
• Analysis and Response
• End user application integration
• Internal operations enablement

What You Will Do

• Lead from Problem Space, Not Solution Space: Engage at the problem-framing stage, facilitating workshops with PMs, UX, and engineers to surface real customer constraints.
• Own Integration Contracts as Product Artefacts: Manage durable interfaces — APIs, event contracts, data schemas — that connect ECS capabilities to the broader Mimecast platform.
• Build the Architectural Context: Produce clear, reasoned, and durable artefacts that let engineering teams and AI-assisted development workflows make consistent decisions at scale.
• Govern Without Blocking: Introduce structure and discipline where they reduce risk or improve quality, engaging the Chief Architect early.
• Reason About Cost and Unit Economics: Model cost trajectories for new architecture work and flag unexpected spend with proposed remediation.
• Communicate at Every Altitude: Operate across various registers, producing decision records, solution briefs, and strategy narratives.

What You Will Bring

• 10+ years building and operating production SaaS systems, with at least 3 years in a Solutions Architect, Principal Engineer, or equivalent role.
• A genuinely broad architectural lens, thinking about system shape, data flows, and organisational constraints.
• Prior close collaboration with Product Managers and UX designers, with an understanding of jobs-to-be-done framing.
• Genuine customer orientation: asking what problem the customer has before asking how to build the feature.
• An understanding of what twenty years of software history means in a production system.
• A proactive self-starter who identifies the right problems to work on without being told.
• Able to reach a solution even without all the knowledge in front of them.

Bonus Points

• Background in email security, threat detection, DLP, identity, or data platforms.
• Familiarity with agentic AI, MCP (Model Context Protocol), or LLM application architecture.
• Experience with eval design for AI features, product discovery practices, or data contract / data mesh approaches.

What We Offer

• Impact: architecture decisions that protect millions of mailboxes and shape the technical direction of one of Mimecast's core product pillars.
• Voice: a direct working relationship with the Chief Architect and a genuine say in technology direction.
• Senior peers: a small, high-trust Architecture Leadership Team where everyone operates at a high level.

Qualifications

• Bachelor's degree in Computer Science, Software Engineering, or a related field — or equivalent demonstrable experience.
• 10+ years of professional software engineering and architecture experience, with at least 3 years in a senior architecture or principal engineering role.
• A track record of product-shaping responsibility, not just technical delivery.
• Active, daily use of AI development tools in a professional setting.

Mimecast is an equal opportunity employer committed to an inclusive and diverse workplace.