Security Engineer

About Mercor

Mercor is training models that predict how well someone will perform on a job better than a human can. We use our platform to source, vet, and onboard expert contractors who help train AI models in a wide variety of domains. Our technology is so effective it’s used by all of the top 5 AI labs.
We scaled from $1-500M in revenue run rate in the last 17 months, making us the fastest growing company in the world. Our growth is accelerating. We averaged 11% week over week growth in July, 18% WoW growth in August, and 19% WoW growth in September. The team is small and we remain profitable because we can’t hire great people as quickly as revenue is growing.

About the Role

As a Security Engineer at Mercor, you’ll own the responsibility of safeguarding our systems, infrastructure, and data. You’ll design and implement defenses, monitor for threats, and ensure security is integrated across the entire development and deployment lifecycle. This role is ideal for someone who thrives in fast-moving environments, can anticipate risks before they materialize, and loves building practical, scalable security systems without slowing down innovation.

What You’ll Work On

• Designing and implementing security controls across infrastructure, applications, and networks.

• Monitoring for vulnerabilities, threats, and suspicious activity.

• Performing penetration tests, vulnerability assessments, and incident response.

• Embedding security practices into CI/CD pipelines and development workflows.

• Ensuring compliance with frameworks such as SOC 2, ISO 27001, and GDPR.

• Partnering with engineers to ensure security is a first-class part of system design.

• Researching emerging threats and implementing countermeasures proactively.

What We’re Looking For

• Strong knowledge of security principles, tools, and best practices.

• Experience with SIEMs, IDS/IPS, firewalls, and vulnerability scanning.

• Familiarity with cloud security (AWS, GCP, or Azure).

• Solid understanding of encryption, authentication, and authorization systems.

• Proven track record of securing distributed, high-scale environments.

• Strong collaboration and communication skills.

• Ability to balance security rigor with business speed in a hyper-growth environment

Why Mercor

• Impact: Your work powers how the world’s leading AI labs train and test their models.

• Learning: Get early insights into frontier model capabilities months before the market.

• Growth: Work on both infrastructure and research-adjacent projects with fast paths to ownership.