Webapp Offensive Security Software Engineer (San Francisco)

Get to Know Us

Horizon3.ai is a fast-growing, remote cybersecurity company dedicated to the mission of enabling organizations to proactively find and fix and verify exploitable attack vectors before criminals exploit them. Our flagship product, the NodeZeroTM platform, delivers production-safe autonomous pentests and other key assessment operations that scale across the largest internal, external, cloud, and hybrid cloud environments. NodeZero has been adopted by organizations of all sizes, from small educational institutions to government agencies and Global 100 enterprises. It is used by ITOps / SecOps teams, consulting pentesters, and MSSPs and MSPs.

We are a fusion of former U.S. Special Operations cyber operators, startup engineers, and formerly frustrated cybersecurity practitioners. We're committed to helping solve our common security problems : ineffective security tools, false positives resulting in alert fatigue, blind spots, checkbox security culture, cybersecurity skills shortage, and the long lead time and expense of hiring outside consultants. Collectively, we are a team of learn it alls, committed to a culture of respect, collaboration, ownership, and results.

Summary

We're looking for an Offensive Security Software Engineer with extensive web application penetration testing experience and a growing interest in AI-enhanced security techniques. You will have a significant impact on how we deliver value to our customers by designing, developing, and integrating web application penetration testing content into the NodeZero platform. This position requires practical expertise in full-scope web application testing, proven software development skills, and enthusiasm for leveraging emerging AI technologies to advance offensive security capabilities.

Essential Functions

Design, develop, and integrate web application offensive security content into the NodeZero platform

Design, develop, and integrate novel attack capabilities into the NodeZero platform, including offensive security tooling and AI-enhanced techniques.

Research and implement AI-driven methods for vulnerability detection, exploitation, and workflow automation.

Extend and maintain platform architecture, data models, and system design to support new product features.

Monitor production for issues or missed opportunities and create or resolve Jira tickets as needed.

Integrate open-source and in-house tools, ensuring quality through testing, code reviews, and production monitoring.

Investigate, own, and resolve bugs in developed content.

Collaborate cross-functionally to address customer and prospect concerns related to attack content.

Author technical blog posts showcasing new research, exploits, or attack methodologies.

Mentor junior engineers and contribute to continuous improvement of team processes and standards

Competencies / Requirements

Experience conducting full scope web application pentests

Experience with proxy tools like Burp and with browser developer tools

Proficient in object-oriented programming and test-driven development, with strong analytical and problem-solving skills.

Experience applying AI-assisted development tools to security research and automation tasks

Curiosity about emerging AI technologies.

Skilled in designing, evaluating, and communicating technical solutions across systems, APIs, algorithms, and data structures.

Familiarity with relational and graph databases, particularly Postgres and Neo4j.

Strong written and verbal communication, including technical documentation.

Ability to manage multiple priorities, work independently, and mentor teammates of varying experience levels.

Quick to learn and adopt new technologies as needed.

History of recognized security research, including documented CVE discoveries and responsible disclosure

Track record of successful bug bounty contributions

Desired / Nice to Have

Experience developing software and automation to aid in web application pentesting

Background in large-scale software development projects.

Experience fine-tuning language models or implementing retrieval-augmented generation (RAG) for security-focused applications.

Experience with AI / LLM tools for building agentic workflows (e.g., LangChain, LangFlow) and integrating contextual data using protocols like Model Context Protocol (MCP).

Expectations :

Outstanding problem-solving aptitude.

Be self-motivated and highly energetic to have the ability to operate effectively with limited supervision and guidance.

Work with our security researchers to understand the technical aspects of reverse engineered exploits and weaponizing these exploits into the product.

Strong technical documentation and communicationskills.

Document findings, methodologies, and recommendations for both technical and non-technical stakeholders.

Proficient in designing, presenting, and evaluating technical solutions.

What makes you stand out :

Demonstrated examples of using AI to enhance or automate exploit development

OSCP (Offensive Security Certified Professional) Certification

Travel Required

We are a fully remote company, and this job may require up to 15% of travel to be successful. Job-related travel expenses are reviewed and must be approved by your manager.

Perks of Horizon3.ai

Inclusive Team : We value diversity and promote an inclusive culture where everyone can thrive.

Growth Opportunities : Be part of a dynamic and growing team with numerous career development opportunities.

Innovative Culture : Work in a collaborative environment that encourages creativity and out-of-the-box thinking.

Remote Work : We are a 100% remote company. Enjoy the convenience and work-life balance that comes with remote work.

Competitive Compensation : We offer competitive salary and benefits which includes health, vision & dental care for you and your family, a flexible vacation policy, and generous parental leave.

Compensation and Values

At Horizon3, we believe that our people are our greatest asset, and our compensation philosophy reflects this core value. We are committed to fostering an environment where all employees feel valued, respected, and rewarded for their contributions. Our compensation structure is designed to be fair, competitive, and transparent, ensuring that every team member is recognized and compensated equitably across roles, levels, and locations.

In accordance with various State's transparency regulations, we provide the following salary range information for this position :

Base salary range : $185,000 - $240,000 annually . The exact salary will be determined based on the selected candidate's location, qualifications, experience, and relevant skills.

Additional compensation : This role may also be eligible for an equity package (in the form of stock options). If any other compensation benefits apply, they will be discussed during the interview process.

You Belong Here

Horizon3 is not just an equal opportunity employer - we are a community that values diversity, equity, and inclusion as fundamental principles of our culture and success. We are dedicated to fostering a workplace where everyone feels welcome and respected, regardless of race, color, religion, sex, national origin, age, disability, veteran status, sexual orientation, gender identity or expression, genetic information, marital status, or any other legally protected status by law.

Our commitment to diversity and inclusion means we strive to attract, develop, and retain a workforce that reflects the varied communities we serve. We believe that diverse perspectives drive innovation and strengthen our ability to create cutting-edge cybersecurity solutions. At Horizon3, every team member is valued and supported in an environment that encourages personal and professional growth.

We welcome candidates from all backgrounds and experiences, and we encourage all qualified individuals to apply. Come be a part of Horizon3, where your unique contributions are recognized, and your potential is limitless.

Other Duties

Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee. Duties, responsibilities, and activities may change at any time with or without notice.

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