Software Engineer I

In this foundational role, you'll work on endpoint sensor technology that runs continuously and reliably on corporate machines across Windows, macOS, and Linux. You'll work at the lowest levels of the operating system, building kernel drivers and Endpoint Security extensions that power how Incydr detects and stops data loss and insider risk. You'll build features end to end, from early research and proof of concept through production at scale.

Mimecast is an AI-First engineering organization. Our teams actively leverage AI-powered development tools across all facets of engineering, and we're looking for someone genuinely curious about working this way—including bringing that curiosity to securing the AI-driven workflows this role increasingly has to defend against.

What You'll Do

• Implement features and fixes within our Windows, macOS, and Linux agents, starting with well-scoped pieces and growing toward owning small features end to end.
• Work at the OS boundary on kernel-mode components and Endpoint Security and Network Extensions, developing greater independence as you build platform depth.
• Contribute to detection paths and inline enforcement logic, progressing from guided implementation toward ownership of specific paths.
• Integrate agent capabilities with backend and product workflows, initially through existing integration points and later by designing new ones.
• Build observability, performance, and stability into always-on production components, supported by mentorship from senior engineers.
• Develop a security-first mindset by reasoning about untrusted input, evasion, and insider risk—not just external attackers.
• Explain and defend the code you ship in review, including code drafted with AI assistance, and demonstrate why it is correct rather than relying only on passing results.

What You'll Bring

• Experience building production software through professional work, internships, coursework, or hands-on personal projects, with readiness to deliver well-scoped work and grow toward owning small features independently.
• Sound C++ fundamentals, including an understanding of memory management, concurrency, and performance trade-offs.
• Interest in systems programming on Linux, macOS, or Windows, with hands-on exposure to areas such as kernel-mode drivers, Windows Filtering Platform, Endpoint Security or Network Extensions, eBPF, or similar technologies.
• Ability to read and understand existing software architecture and make small, sound architectural decisions as your scope grows, including decisions around interface boundaries and extensibility.
• A security-curious mindset and the ability to reason about adversarial behavior and insider risk.
• Comfort using AI coding assistants, paired with the discipline to independently verify, understand, and take responsibility for their output.
• Coachability and a track record of turning feedback into stronger design and code quality over time.
• Experience with Rust, Swift, or systems-level Linux development is a plus.
• Cross-platform development experience across Windows, macOS, and Linux is a plus.
• Exposure to network-layer monitoring, data security, or data loss prevention concepts is a plus.
• Experience shipping enterprise software—including installation, automatic updates, or multi-tenant configuration—is a plus.
• A portfolio, such as GitHub projects, a technical blog, or coursework, demonstrating genuine hands-on systems work is a plus.

The base salary range for this position is $100,000-$150,000 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 careers@mimecast.com.

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.