Principal Machine Learning Engineer

About Mimecast

The work people build is worth protecting, and it's harder to protect than it used to be. AI agents now move at machine speed with human-level access, and a small slip-up can become a very public one. We disrupt cybercriminal activity before that happens. We think fast, go big, and always demand more of ourselves. We work hard, deliver, and repeat. We grow with real determination and put success well within reach. We push each other to be better and expect to be pushed back, in a community built on respect, where everyone is counted.
Work Protected.

Overview

As a Principal Machine Learning Engineer, you will set technical direction for Mimecast's ML capabilities, including our GCI products or advanced email threat-detection products. This is a senior individual-contributor role: you will own the hardest modeling and systems problems end to end, define the architecture other engineers build on, and be a technical authority for product and engineering leadership when the direction is not obvious.

Our threat ML runs on Mimecast's shared AI enrichment platform, the detection and extraction infrastructure serving models across the product suite. You will work at the intersection of applied ML, production model serving, and cross-team integration, making architectural decisions that hold up under production load and customer commitments.

Mimecast is an AI-first engineering organization. You will use AI development tools, including Claude Code, Cursor, and MCP integrations, in your daily work and establish the workflows, patterns, and quality bar for the team. You will also design product systems using LLM and agent-based patterns.

Employees are expected to work from the office at least two days per week. This fosters collaboration, communication, performance, and learning; drives innovation and creativity within and between teams; introduces employees to priorities beyond their immediate realm; and supports important interpersonal relationships and connections.

What You'll Do

Develop and own ML systems end to end, from data sourcing, cleaning, and labeling strategy through feature engineering, model development, deployment, and monitoring.
Set the ML architecture across model design, serving, and surrounding systems, optimizing accuracy, latency, and throughput for highly imbalanced threat-detection data.
Set technical direction for production model serving using AWS SageMaker, NVIDIA Triton Inference Server, ensemble/KServe patterns, hardened container images, and integration with enrichment and gateway layers.
Benchmark and prototype alternatives to de-risk major decisions, then give leadership defensible technical recommendations.
Establish reproducible ML standards, including versioned datasets, region-partitioned data, and shared experimentation workflows.
Make model observability and efficacy measurement first-class concerns through distributed tracing, threshold-independent metrics, raw-payload capture, and monitoring for real regressions.
Own capacity planning and rollout strategy, including throughput per core or GPU, utilization headroom, peak-load provisioning, and phased regional canary or shadow deployments.
Diagnose production incidents, close the structural gaps they expose, and act as a primary reviewer and mentor across the ML codebase.
Partner with Product, platform engineering, and adjacent teams to shape the roadmap and communicate technical complexity and business implications through engineering and product leadership.

What You'll Bring

Breadth across transformer architectures, RNNs, CNNs, generalized linear models, and gradient-boosted trees, with the judgment to select the right approach for the problem rather than defaulting to the largest model.
Deep Python proficiency and strong command of PyTorch, Hugging Face transformers, and NLP tooling, plus working knowledge of ONNX Runtime, quantization such as FP16, and inference acceleration.
Experience with dense and lexical retrieval, including embeddings, vector indexes and approximate nearest-neighbor search, BM25, TF-IDF, and hybrid approaches.
Experience working with datasets exceeding two million examples and highly imbalanced data, using rigorous evaluation methods for precision and recall trade-offs, threshold selection, and test-set leakage prevention.
A track record of owning production ML systems on AWS, including SageMaker, S3, Athena, Lambda, Glue, Kinesis, and Bedrock, with Terraform, IAM, containers, and Kubernetes-based deployment.
Working knowledge of model-serving frameworks such as TorchServe, FastAPI, and NVIDIA Triton Inference Server/KServe, and the trade-offs among throughput, GPU efficiency, flexibility, and speed of iteration.
Hands-on experience running CUDA workloads in production, including driver, toolkit, and runtime alignment; GPU passthrough in containers; debugging GPU failures; and improving GPU utilization.
Fluency with AI-native development tools and modern LLM application patterns, including OpenAI-style chat-completion and structured tool/function-calling APIs, MCP, and agent frameworks.
Demonstrated technical leadership as an individual contributor, including setting direction, mentoring engineers across seniority levels, and communicating technical decisions and their business implications to technical and executive audiences.
An understanding of handling sensitive data in accordance with Master Service Agreements and compliance requirements.
A Ph.D. or Master's degree in a quantitative discipline, such as computer science, statistics, or mathematics, with substantial experience applying advanced ML to production problems; or equivalent depth demonstrated through a Bachelor's degree and a longer track record. We value demonstrated technical authority over a specific year count.

The base salary range for this position is $172,000 - $258,000 USD plus benefits. This range represents the minimum and maximum new hire compensation for this role. The position may also be eligible for incentive plans and additional benefits, in accordance with company policy and local regulations. Our salary ranges are determined by role, level, and location with individual compensation also dependent on factors such as qualifications, experience, and skills. Final offers will reflect these considerations and may vary accordingly.

Belonging at Mimecast

Cybersecurity is a community effort. That’s why we’re committed to building an inclusive, diverse community that celebrates and welcomes everyone – unless they’re a cybercriminal, of course.

We’re proud to be an Equal Opportunity and Affirmative Action Employer, and we’d 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 won’t affect your application.

If you require any adjustments or accommodations due to a disability, or any other reason that may help you in your interview process, please let us know by emailing [email protected].

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.

About the company

Mimecast provides cloud-based cybersecurity services focused on email. It blocks phishing, malware, and spam, archives and indexes emails for compliance, and offers continuity to keep email access during outages. Revenue comes from subscription plans and it integrates with other cybersecurity tools to form a broader security stack for SMEs to large enterprises. Its goal is to reduce email-based risk, protect data integrity, and ensure uninterrupted communications across client organizations.

Company Size

1,001-5,000

Company Stage

IPO

Headquarters

London, United Kingdom

Founded

2003

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Simplify's Take

What believers are saying

Ranjan Singh became CEO on June 25, 2026, accelerating platform-led execution.
Agent Risk Center beta started August 2026, targeting shadow AI and autonomous agents.
Exclusive Networks and blueAPACHE partnerships expanded Mimecast distribution in India and Australia.

What critics are saying

Mimecast suffered 2026 console and mail-delivery incidents across UK, AU, US, and ZA grids.
Incydr and Agent Risk Center face crowded rivals like Microsoft, Proofpoint, and Palo Alto Networks.
AI governance positioning is existentially risky if enterprises standardize on native Microsoft 365 controls.

What makes Mimecast unique

Mimecast serves 42,000 organizations and 27 million users across 100 countries.
Its 2026 platform unifies email security, archiving, Incydr, and AI-agent governance.
Mimecast’s behavioral telemetry spans 24 trillion annual signals across email, collaboration, and AI.

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Benefits

Health Insurance
Hybrid Work Options
Performance Bonus

Growth & Insights and Company News

Headcount

6 month growth

1 year growth

2 year growth

Marketing Spread

Oct 7th, 2026

Windhoek summit to tackle the cyber gaps AI is exposing.

Windhoek summit to tackle the cyber gaps AI is exposing. Namibian business and technology leaders will come together in Windhoek on 13 October for the 2026 Namibian Cyber Security Summit, hosted by The Cloud Crew and DigitalShield, as organisations face growing pressure to understand where their existing cyber defences may still leave them exposed. The summit, themed 'Mind the Gaps, AI, Governance and Cyber Defense', takes place at The Weinberg Hotel from 08:00 to 15:00 and will bring together IT, security, governance, risk, and business leaders for a practical examination of the gaps that can develop across technology, people, and processes. Figures from the Namibia Cyber Security Incident Response Team show that 161,547 cyber events were recorded between April and June 2026, up 56.7% from the previous quarter, while more than 513,000 cyber vulnerabilities were detected during the same period. A clearer view of the gaps Most organisations know which security tools they have in place. However, it is more difficult to understand the gaps that sit between these solutions, who takes ownership when something falls outside a tool's remit, and whether the overall environment is as well covered as everyone assumes. The summit will use the Cyber Defense Matrix as a practical way to examine that problem. The framework maps core cyber security functions to the assets organisations need to protect, helping security teams understand where existing capabilities are concentrated and where gaps may exist. It also recognises that technology alone cannot carry the entire security programme, particularly as detection, response, and recovery increasingly depend on people and processes. AI changes the security map AI adds another layer to an already complex environment. Employees may be using AI tools before formal governance catches up, while security teams are also beginning to use AI to identify risk and accelerate analysis. "AI is being adopted faster than many organisations can update their policies, controls, and ways of working," says Aidan Snyders, Business development Manager of The Cloud Crew. "The risk is that new capability gets introduced in pockets across the business without anyone having a complete view of what it can access or how it should be governed. The summit is designed to help leaders get that visibility and make practical decisions about where they need to tighten control." The programme will look at how vulnerability management connects with governance, how organisations can establish where AI is already being used, and what human behaviour still means for cyber risk. It will also examine agentic defence and the growing role of machines in triaging security activity before a human analyst becomes involved. The Cloud Crew and DigitalShield will be joined by alliance partners Netskope, Mimecast, and CrowdStrike, bringing different perspectives on how organisations can strengthen cyber resilience without losing sight of the operational realities behind the technology. Registration is open The summit is aimed at leaders responsible for technology, cybersecurity, governance, risk, and business operations who want a clearer view of where existing controls may need attention as AI becomes more deeply embedded in the organisation. Registration and networking begin at 08:00, with formal sessions running through the morning before lunch and networking from 12:00. Attendees will also be entered into a lucky draw to win an iPad. 'Mind the Gaps, AI, Governance, and Cyber Defense' takes place at The Weinberg Hotel, 13 Jan Jonker Street, Klein Windhoek, on 13 October 2026.

International World Times

Oct 5th, 2026

The Top Email Security Software vendors according to the FeaturedCustomers Fall 2026 Customer Success Report rankings.

The Top Email Security Software vendors according to the FeaturedCustomers Fall 2026 Customer Success Report rankings. FeaturedCustomers releases the Fall 2026 Email Security Software Customer Success Report. COOPER CITY, FL, UNITED STATES, October 5, 2026 / EINPresswire.com / - Today FeaturedCustomers published the Fall 2026 Email Security Software Customer Success Report to give prospects better insight on which Email Security Software would work best for their business according to real customer references. The highest rated vendors according to the Fall 2026 Email Security Software Customer Success Report are: Market Leaders - Abnormal AI, Barracuda Networks, Check Point Software, Cofense, Fortra, Mimecast, Proofpoint, SonicWall, and TitanHQ were given the highest "Market Leader" award. Market Leaders are vendors with a substantial customer base & market share. Market Leaders have the highest ratio of customer reference content, content quality score, and social media presence relative to company size. Top Performers - GoSecure, Guardian Digital, Hornetsecurity, IRONSCALES, SilverSky, Valimail, and VIPRE were awarded "Top Performer" honors. Top Performers are vendors with significant market presence and enough customer reference content to validate their vision. Top Performers' products are highly rated by its customers but have not achieved the customer base and scale of a Market Leader relative to company size. Rising Stars - EasyDMARC, GajShield, MailGuard, Paubox, and Zivver were awarded the "Rising Star" honor. Rising Stars are vendors that do not have the market presence of Market Leaders or Top Performers but understand where the market is going and has disruptive technology. Rising Stars have been around long enough to establish momentum and a minimum amount of customer reference content along with a growing social presence. About the Fall 2026 Email Security Software Customer Success Report: The customer success report is based on over 5,000 pieces of verified customer reference content. A vendor's overall customer success score is reached via a weighted average of their Content, Market Presence, and Company Scores. Of the vendors listed in the FeaturedCustomers' Email Security Software category, 21 vendors met the minimum requirements needed to be considered for the customer success report. About FeaturedCustomers: FeaturedCustomers, the world's only customer reference platform for B2B business software and services, helps potential B2B buyers research and discover business software and services through vendor validated customer reference content such as customer testimonials, success stories, case studies, and customer videos. Every day the platform helps influence the purchasing decisions of thousands of B2B buyers in the final stages of their buying cycle from Fortune 500 companies to SMB's. For more information, visit https://www.featuredcustomers.com. Legal Disclaimer: EIN Presswire provides this news content "as is" without warranty of any kind. International World Times do not accept any responsibility or liability for the accuracy, content, images, videos, licenses, completeness, legality, or reliability of the information contained in this article. If you have any complaints or copyright issues related to this article, kindly contact the author above.

iConnectITBS

Sep 14th, 2026

iConnect named Cybersecurity System Integrator of the Year at TahawulTech Channel Leadership Forum & Awards 2026.

iConnect named Cybersecurity System Integrator of the Year at TahawulTech Channel Leadership Forum & Awards 2026. * 14 September 2026 Dubai, UAE | September 2026 iConnect has been named Cybersecurity System Integrator of the Year at the TahawulTech Channel Leadership Forum & Awards 2026. The award recognises the company's work in delivering cybersecurity solutions and services to organisations across the region. It acknowledges iConnect's focus on helping organisations strengthen their security environments through the integration of cybersecurity technologies, managed security services and enterprise security solutions. About the TahawulTech Channel Leadership Forum & Awards. The Channel Leadership Forum & Awards is TahawulTech's annual gathering for the Middle East technology channel. The 2026 edition was held on 14 September at The Westin Dubai Mina Seyahi Beach Resort & Marina and brought together senior technology executives, vendors, distributors, resellers and systems integrators from across the region. The programme combined industry discussion with an awards ceremony. Charbel Zreiby, Head of Channel and Distribution, EMEA East at Veeam, delivered the keynote on the changing role of channel leadership, and a panel titled "Channel Leadership 3.0" examined how AI is shaping distribution and partner ecosystems in the region. The awards recognise companies and leaders for their performance, innovation, partner commitment and contribution to industry growth across the technology channel, including cybersecurity, systems integration, managed services and digital transformation. This year's winners also included Cloudflare, Veeam, NTT DATA, Dell Technologies, Hitachi Vantara, Commvault and Mindware. What the award recognises. A cybersecurity systems integrator designs, deploys and supports security technologies so that they work together as one environment rather than as separate products. This covers the assessment of an organisation's existing controls, the selection and implementation of technologies from multiple vendors, the integration of those technologies with existing infrastructure, and ongoing operation and support once they are live. iConnect delivers this work through its own cybersecurity consulting, implementation and managed services teams in the UAE, working with security technology partners including BeyondTrust, KnowBe4, Fortinet, CrowdStrike, Palo Alto Networks, Microsoft and Mimecast. The full list is on the partners page. iConnect's cybersecurity services. The recognition comes as iConnect continues to expand its cybersecurity capabilities across the UAE and the wider Middle East. Its services cover Security Operations, Managed Detection and Response, Vulnerability Assessment and Penetration Testing, Identity and Access Management, Privileged Access Management, Email Security, Cloud Security and other enterprise security requirements. iConnect also operates an in-house Security Operations Center (SOC) in the UAE, providing continuous security monitoring and response for its customers. A decade of building in the region. iConnect was founded in Dubai in 2016. It opened its in-house cybersecurity service centre in the UAE in 2017, followed by a Network Operations Centre in 2018. In 2022 the company established a dedicated cybersecurity consulting practice, and in 2023 it expanded into Abu Dhabi and joined the UAE's In-Country Value (ICV) programme. Operations were extended to Saudi Arabia in 2024. The company's services are delivered under an ISO 9001 quality management system. Read more about iConnect. A message from its Co-Founder. Daljeet Singh, Co-Founder & Director of Business Development at iConnect, said: "Receiving the Cybersecurity System Integrator of the Year award is a proud moment for everyone at iConnect. It reflects the commitment of its teams and the trust its customers and partners place in Iconnect IT Business Solutions. Cybersecurity requires the right combination of technology, expertise and integration to address the security needs of each organisation. Its team continues to focus on delivering solutions that are practical, effective and aligned with the environments its customers operate in. Iconnect IT Business Solutions thank TahawulTech for this recognition, and its customers and technology partners for their continued trust and support. Iconnect IT Business Solutions look forward to building on this achievement and continuing to strengthen its cybersecurity capabilities across the region."

Spadez Store

Sep 8th, 2026

SpadezStore partners with Mimecast to offer email security solutions.

SpadezStore partners with Mimecast to offer email security solutions. September 8, 2026 In today's fast-evolving digital landscape, cybersecurity and communication continuity are no longer optional - they're mission-critical. At SpadezStore, SpadezStore LLC is proud to support businesses looking to streamline their operations and fortify their digital infrastructure through Mimecast, one of the world's leading cloud-based email security and cyber resilience platforms. What is Mimecast? Mimecast is an all-in-one cyber resilience platform that helps organizations protect their email, data, and people from evolving threats. From email security and archiving to awareness training and brand protection, Mimecast offers a comprehensive suite of tools built for businesses of every size. Why integrate through SpadezStore? As a trusted provider of IT solutions, SpadezStore bridges the gap between enterprise-grade technology and the businesses that need it most. Its Mimecast integration offering gives you: * Simplified onboarding - SpadezStore LLC handle the technical setup so your team can focus on what matters

Help Net Security

Aug 3rd, 2026

Mimecast introduces AI agent governance and managed threat response.

Mimecast introduces AI agent governance and managed threat response. Mimecast has unveiled Agent Risk Center, a beta capability for discovering, monitoring, and governing AI agents, alongside Managed Threat Response, a redesigned 24/7 service that combines AI-assisted triage with analyst-confirmed remediation. According to Mimecast's analysis, 98% of organizations already have unsanctioned AI tools in use, and by 2029 more than a billion agents will take some 217 billion actions a day1 on employees' behalf with limited visibility for security tools. The Mimecast Agent Risk Center gives security and risk teams one place to see who is behind that activity and act on it, applying the same risk lens Mimecast already applies to human insiders. "AI agents are being deployed faster than security teams can see them," said Rob Juncker, Chief Technology & Product Officer, Mimecast. "Most organizations don't know what agents are running in their environment, what data they're touching, or who's accountable when something goes wrong. Mimecast Agent Risk Center changes that - same risk model, same controls, extended to every agent acting on behalf of your people." Mimecast Agent Risk Center: beta now open. As enterprises deploy AI agents across email, collaboration, and business workflows, security teams face a growing risk surface with limited visibility into agent behavior, permissions, and data access. Mimecast Agent Risk Center gives security and risk teams a single point of control to discover, monitor, and govern AI agents operating in their environment. Key capabilities include: * Unified Agent Dashboard - a single, real-time inventory of every AI tool and connection, sanctioned or not * AI Rulebook - governance for classifying and enforcing policy by department, with no new deployment required * Response Controls - desktop app blocking, browser upload and paste blocking, and in-context user nudges The Mimecast Agent Risk Center is in beta as a free, opt-in capability for active Incydr subscription customers, with early access in September 2026 and general availability for those customers planned for January 2027. Managed Threat Response: AI-accelerated triage, analyst-confirmed remediation. Mimecast also introduced Managed Threat Response, a redesigned 24/7 managed service that combines AI and human expertise to address one of security's most persistent problems: uninvestigated alerts. Research shows that 42% of security alerts go entirely uninvestigated.2 Mimecast closes that gap for emails flagged by users, taking on 100% of the queue and remediating confirmed threats. Mimecast AI triages every reported email. Mimecast Security Operations Center analysts then action confirmed threats - blocking senders or domains, removing campaigns tenant-wide, and updating detection logic based on confirmed outcomes. Customers see the outcome, not the work: no new console, no model to tune, no analyst headcount to fund. Detection logic improves continuously as confirmed threats are identified across Mimecast's 42,000-customer base. More about

Mimecast

Principal Machine Learning Engineer

About the job