Senior Solution Architect - Email & Collaboration Security

Senior Solutions Architect – Email & Collaboration Security – London UK

Why This Role Exists 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. Reasoning about legacy shape and evolutionary trajectory simultaneously is not optional; it is the job. 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.

Mimecast is an AI-first engineering organisation. This is not a cultural aspiration — it is an operating expectation. 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: understanding the implications of LLM integration, agent boundaries, prompt and data-contract stability, and evaluation coverage for AI-driven features. Candidates who treat AI tooling as optional or experimental are not the right fit for this role. The expectation is fluency and daily practice, not passing familiarity.

ECS covers the following product and capability areas:
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

The role engages at the problem-framing stage, not after requirements have already hardened into tickets. This means facilitating workshops with PMs, UX, and engineers to surface real customer constraints and articulate what good looks like in business and user terms before any technical shape is proposed.

The durable interfaces — APIs, event contracts, data schemas — that connect ECS capabilities to the broader Mimecast platform are first-class artefacts owned by this role. They outlast individual features, and the coordination work that makes integrations actually land across teams and time is part of the remit.

Engineering Teams Operate Inside ADRs, service interaction patterns, NFR targets, and data contracts are not documentation — they are the substrate that lets engineering teams and AI-assisted development workflows make consistent decisions  artefacts produced in this role are clear, reasoned, and durable.

Governance is a mechanism for alignment and acceleration, not gatekeeping. Structure and discipline are introduced where they reduce risk or improve quality — and removed where ceremony adds cost without value. The role engages the Chief Architect early, pushes back constructively when platform standards do not fit the ECS context, and helps teams close decisions with conviction rather…