Description:

LMArena is seeking an experienced Senior Security Engineer to lead the design and implementation of systems to combat bots through real-time and post-processing systems.
The role focuses on safeguarding systems that power real-time AI evaluation, particularly in detecting and mitigating Sybil attacks and other forms of adversarial manipulation.
The engineer will ensure that Arena remains a trusted and resilient platform for users, developers, researchers, and organizations relying on transparent, community-driven AI benchmarks.
Responsibilities include designing and implementing robust security frameworks, conducting threat modeling and risk assessments, and collaborating with the engineering team to create Sybil-resistant protocols.
The engineer will develop tools to monitor, detect, and respond to security threats in real time and stay updated with the latest research in Sybil attack mitigation and distributed systems security.
The role involves leading incident response efforts during security breaches, educating the team on security best practices, and maintaining a comprehensive threat model that includes identification of attack vectors and categorization of adversarial behaviors.

Requirements:

Candidates must have 5+ years of experience in software engineering or security engineering, focusing on building secure, scalable systems.
Proven experience in designing and deploying infrastructure security measures across cloud environments, identity systems, and access controls is required.
Hands-on experience with user fingerprinting techniques, identity modeling, or behavioral analytics to prevent fraud or abuse is necessary.
Experience in designing and defending against Sybil attacks, bot activity, or adversarial manipulation at the platform level is essential.
Strong knowledge of threat modeling, risk assessment, and designing mitigation strategies for real-world attack scenarios is required.
Familiarity with common security tools and practices, including VPNs, MFA/2FA, intrusion detection, secrets management, and secure deployment pipelines is expected.
Candidates should be clear communicators who can collaborate cross-functionally and articulate risks and tradeoffs to both technical and non-technical stakeholders.
Bonus points for experience in adversarial ML, trust & safety systems, or securing user-driven platforms with voting or reputation systems.

The position offers a salary range of $210k - $231k plus equity, with actual compensation depending on job-related knowledge, skills, experience, and candidate location.
Employees receive a competitive salary and meaningful equity.
Comprehensive healthcare coverage, including medical, dental, and vision, is provided.
The opportunity to work on cutting-edge AI with a small, mission-driven team is available.
The company fosters a culture that values transparency, trust, and community impact.