Senior Solution Architect - Email & Collaboration Security in London

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.

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, while removing unnecessary ceremony.
• 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 Senior Architect or equivalent role.
• A broad architectural lens, thinking about system shape, data flows, and organisational constraints.
• Comfort operating across cloud-native patterns (AWS, Kafka, managed services).
• Prior close collaboration with Product Managers and UX designers.
• Genuine customer orientation: understanding customer problems before building features.
• Understanding of SaaS unit economics and the commercial implications of architectural choices.
• An understanding of what twenty years of software history means in a production system.
• Structure and discipline as cognitive defaults, producing thorough, well-reasoned artefacts.
• An ability to connect dots across a large picture with many moving parts.
• Self-Direction and Strategic Initiative: A proactive self-starter who identifies the right problems to work on.
• Learning Orientation: Able to reach solutions even without all the knowledge in front of them.
• AI tooling treated as a core capability multiplier.

Bonus Points

• Background in email security, threat detection, DLP, identity, or data platforms.
• Familiarity with agentic AI, MCP, or LLM application architecture.
• Experience with eval design for AI features or data contract approaches.
• Exposure to M365 or GWS integration patterns.

What We Offer

• Impact: architecture decisions that protect millions of mailboxes.
• Voice: a direct working relationship with the Chief Architect.
• Senior peers: a small, high-trust Architecture Leadership Team.

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.
• A track record of product-shaping responsibility.
• Active, daily use of AI development tools in a professional setting.

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