Get to Know Us

Horizon3 is a fast-growing, remote cybersecurity company dedicated to the mission of enabling organizations to proactively find, 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 IT Ops/SecOps teams, consulting pentesters, and MSSPs and MSPs.

We are a fusion of former U.S. Special Operations cyber operators, startup engineers & operators, and formerly frustrated cybersecurity practitioners. We're committed to helping solve our common security problems: ineffective security tools and 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.

What You’ll Do

The Federal - Senior Backend Engineer will be joining one of our world-class software engineering teams, and will be a key contributor to both user-facing product launches as well as platform enhancements and stability. Employee must be eligible for and successfully secure a US Federal Security Clearance as a condition of employment. *This job description covers roles available across multiple teams. During the interview process, we’ll work with you to determine the best team fit based on your experience, interests, and career goals.

Responsibilities:

Develop core product features in ETL (Extract, Transform, Load) and GraphQL to support data processing and retrieval.
Design and implement backend APIs in GraphQL to facilitate data interactions between different components of the product.
Build and maintain ETL pipelines for efficient data processing and analytics.
Collaborate with frontend team members to present data in a clear and user-friendly format, enhancing the product's user experience.

What You’ll Bring

Ability to own and manage concurrent initiatives, demonstrating effective judgment in prioritization and time management.
Driven, self-managed, capable of conceiving and implementing solutions on your own and with a team
A strong desire to continuously improve and learn new technologies in a fast-paced Agile development environment
Excellent analytical and problem-solving skills, effective communication, attention to detail and high-quality work
Strong technical documentation ability to support the development process.
Effective communication and collaboration with designers, developers, and product managers.
Ability and interest in mentoring junior and mid-level engineers to foster their growth and development.

Required Education / Experience:

Bachelor's Degree in Computer Science, Computer Engineering or related field.
7+ yrs professional software engineering experience using modern object-oriented or functional languages (Python, Java, Go, Scala, C++, TypeScript, etc).
Experience building applications on cloud computing platforms such as AWS, Azure, GCP, using container technologies such as Docker and Kubernetes.
Experience building and troubleshooting capabilities in Federally compliant systems such as FedRAMP, IL4/5/6, and other Classified workloads.
Expert proficiency in SQL.
Current Top Secret security clearance or eligibility to gain/maintain a Top Secret clearance.

Preferred Education/Experience:

Experience with various database architectures including relational (PostgreSQL) and graph (Neo4j).
Experience building GraphQL backends.
Experience managing and maintaining production infrastructure.
Experience building platform capabilities for internal teams.
Experience using AI-enabled development tools

Travel Required

We are a fully remote company with a strong preference for candidates located in the
Baltimore, MD / Washington DC area. This job may require up to 5%of travel to be successful.

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: The exact salary will be determined based on the selected candidate’s location, qualifications, experience, and relevant skills.
Additional compensation: All full-time roles are eligible for an equity package in the form of stock options.

Perks ofHorizon3

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 flexibility to work in the way that supports you and brings out your best.
Competitive Compensation: We offer competitive salary, equity and benefits. Our benefits include health, vision & dental insurance for you and your family, a flexible vacation policy, and generous parental leave.

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, hair length 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.

Application Note

In any materials you submit, you may redact or remove age-identifying information such as age, date of birth, or dates of school attendance or graduation. You will not be penalized for redacting or removing this information.

About the company

Horizon3.ai specializes in cybersecurity by offering NodeZero, a SaaS platform for autonomous penetration testing. It lets enterprises simulate cyber-attacks on their own systems in a self-service way, without installing persistent agents, and without ongoing human intervention. The platform works by running security-focused attack simulations in production environments to uncover exploitable vulnerabilities and weak controls, delivering vulnerability assessments, threat simulations, and compliance-oriented testing through tiered subscription plans. This approach differentiates Horizon3.ai from traditional pentesting by being self-service, agentless, and safe to run in live environments, while targeting enterprise customers that must meet standards such as PCI DSS. The company aims to help organizations improve their security posture, prioritize remediation, and maintain regulatory compliance by continuously identifying and fixing weaknesses.

Company Size

501-1,000

Company Stage

Series E

Total Funding

$437M

Headquarters

San Francisco, California

Founded

2019

Get referred to Horizon3.ai

See people who can refer or advise you

Simplify's Take

What believers are saying

August 3, 2026 Series E raised $250 million at over $2 billion valuation.
September 15, 2026 CrowdStrike SIEM integration pushes NodeZero findings into mainstream security operations.
August 2026 Australia sovereign instance and federal hiring expand Horizon3 into regulated, higher-budget markets.

What critics are saying

Pentera and XBOW pressure Horizon3’s pricing and differentiation as autonomous pentesting commoditizes.
Customer trust collapses after one production outage or false exploit path during testing.
Deloitte, CrowdStrike, and WWT can absorb Horizon3 into broader platforms, weakening standalone demand.

What makes Horizon3.ai unique

NodeZero runs production-safe autonomous pentests without persistent agents, unlike consultant-led annual testing.
Horizon3 sells continuous attacker-perspective validation across identity, cloud, web, and on-prem surfaces.
FedRAMP High authorization and sovereign instances differentiate Horizon3 for government and regulated buyers.

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Benefits

Health Insurance
Vision Insurance
Dental Insurance
Unlimited Paid Time Off
Remote Work Options
Stock Options

Growth & Insights and Company News

Headcount

6 month growth

-3%

1 year growth

2 year growth

-2%

Yahoo Finance

Oct 19th, 2026

Horizon3, backed by EDBI and SG Growth Capital, opens ASEAN headquarters in Singapore

Horizon3, an AI-native security company, is expanding in Singapore with new investments from EDBI and its parent SG Growth Capital. The amount was not disclosed. The company is setting up its ASEAN headquarters and a Regional Centre of Excellence there, which will also support its growth in Australia and Japan. It will hire locally across sales, customer and partner teams. The move follows Horizon3's $250 million Series E round in August 2026, which valued it at more than $2 billion. Demand is rising as AI-driven attacks grow. Singapore's Cyber Security Agency reported that infected infrastructure in the country rose 142% in 2025 to 284,300 systems.

Agence France-Presse

Oct 19th, 2026

Horizon3 expands in Singapore to accelerate AI-Native Proactive Security across Southeast Asia.

Horizon3 expands in Singapore to accelerate AI-Native Proactive Security across Southeast Asia. 19 Oct 2026 Horizon3, the AI-native proactive security leader, today announced a strategic expansion in Singapore, supported by new investments from EDBI and its parent SG Growth Capital, the strategic investment platform established by the Singapore Economic Development Board and Enterprise Singapore to support companies from early to growth stages. This expansion is to meet accelerating demand across Southeast Asia for continuous, evidence-based security validation as AI-driven cyberattacks escalate in speed, scale and sophistication. Horizon3 is establishing its ASEAN headquarters and a Regional Centre of Excellence in Singapore, to support its expansion across Australia and Japan as well. The company will also increase its local headcount as it scales its sales, customer and partner operations. The Singapore expansion follows Horizon3's US$250 million Series E funding round announced in August 2026, which valued the company at more than US$2 billion. The expansion aligns with Singapore's national cybersecurity priorities and the broader regional shift from periodic assessments to continuous proof of cyber resilience. Singapore's Cyber Security Agency (CSA) said in its 2025/2026 Singapore Cyber Landscape report that AI is increasingly being used by threat actors to conduct attacks with greater speed, scale and sophistication, while infected infrastructure in Singapore rose 142% in 2025 to 284,300 systems. From periodic testing to continuous security validation As AI and digital environments become more complex, organisations need to know which vulnerabilities can actually be exploited and what an attacker can reach. Horizon3's NodeZero autonomously validates attack paths, provides remediation guidance and retests to verify fixes, giving security teams continuous, evidence-based visibility into real-world exposure. "Singapore's regulatory and national cybersecurity agenda signals a broader shift across the region: boards can no longer rely on confidence or compliance checklists; they must be able to prove cyber resilience and prove they are prepared for AI-enabled cyber warfare," said Snehal Antani, CEO and co-founder of Horizon3. "Our expansion in Singapore, supported by EDBI and SG Growth Capital, positions Horizon3 at the centre of Southeast Asia's digital economy, where we can work closely with customers and partners to move from periodic assessments to continuous, attacker-validated proof of resilience. As AI compresses attack timelines from months to hours, the strategic question for security leaders is not how many vulnerabilities they have, but whether they can continuously validate what is actually exploitable and verify that remediation has reduced business risk." "Horizon3 chose Singapore as our Southeast Asia base because it combines a deep concentration of financial institutions, critical infrastructure operators and regional headquarters with a clear, forward-looking direction on cyber resilience and AI governance," said Gareth Cox, vice president, Asia Pacific and Japan at Horizon3. "From CSA's Cyber Landscape 2025/2026 report and Cyber Trust Mark roadmap to MAS' tightened technology-risk notices, Singapore is setting expectations that security must be measurable, not just documented. This makes it the ideal launchpad for supporting organisations across Malaysia, Indonesia, Thailand and beyond as they shift from tick-box compliance to outcomes-based security. We are working with boards and CISOs to demonstrate, with evidence, that their security investments are closing the attack paths that pose the greatest risk to the business." Strategic Investments from EDBI And SG Growth Capital The investments by EDBI and SG Growth Capital reflect confidence in Horizon3's technology and its fit with Singapore and the region's cybersecurity priorities. "Horizon3 combines differentiated AI technology with a strong track record of helping enterprises adopt continuous security validation and proactively strengthen their security posture," said Yeung Chia Li, senior partner, EDBI. "The establishment of its ASEAN headquarters and Regional Centre of Excellence in Singapore reflects the company's long-term commitment to the region and will contribute to the growth of Singapore's cybersecurity ecosystem. Beyond our investment, we look forward to supporting Horizon3's expansion through access to talent, strategic partnerships and market opportunities across Southeast Asia." Horizon3 will use its Singapore expansion to: * Scale its go-to-market operations across Southeast Asia, including enterprise, mid-market and public-sector segments. * Deepen partnerships with local Managed Security Service Providers (MSSPs), systems integrators and cloud providers to deliver continuous validation at scale. * Collaborate with Singapore's cybersecurity ecosystem, including CSA-led initiatives on AI for cybersecurity and CII resilience. * Help secure the digital transformation in continuous assurances with relations to Singapore's National AI Strategy from the Ministry of Digital Development and Information. About Horizon3 Horizon3, the AI-Native Proactive Security Company behind NodeZero(R), shifts the advantage from attackers to defenders by giving organisations the power to fight AI with AI. NodeZero, the World's Best AI Hacker(TM), autonomously tests defences at machine speed, safely uncovers and prioritises exploitable attack paths, instantly verifies fixes, and drives a continuous hack-fix-verify loop. More than 7,000 organisations, including global defence agencies, Fortune 10 enterprises, multinational banks and major healthcare providers, trust Horizon3 for security they can prove. Horizon3 was recently named the Fastest Growing Cybersecurity Company in North America by the Deloitte Technology Fast 500 and one of the Most Innovative Companies by Fast Company in 2026.

Business News This Week

Oct 17th, 2026

Horizon3 and Pax8 expand European security partnership.

Horizon3 and Pax8 expand European security partnership. AMSTERDAM, Oct 17 - Horizon3, the AI-Native Proactive Security Company, today announced the expansion of its Pax8 partnership across Europe, bringing the NodeZero(R) Proactive Security Platform to the region's managed service providers (MSPs) through the Pax8 Marketplace. The expansion enables partners to build recurring security services that help small and midsized businesses understand how attackers could compromise their environments, prioritize corrective actions, and verify remediation. Building on the companies' North American marketplace launch, the European expansion makes autonomous offensive security testing accessible to more MSPs and the businesses they protect. Partners can use NodeZero to deliver initial assessments, support remediation engagements, and establish ongoing testing programs without conducting every penetration test manually. Discover more News article writing Weekly business insights Economic growth analysis "MSPs are accountable for protecting their customers' security, but a list of vulnerabilities does not tell them what is actually exploitable, and their level of exposure," said Keith Poyser, General Manager & SVP EMEA, at Horizon3. "NodeZero gives partners that information and a way to fix, and then verify these exploits are remediated. Expanding our relationship with Pax8 brings this capability to more MSPs across Europe, helping them build services around measurable reductions in customer exposure and continuous testing." From Individual Weaknesses to Proven Attack Paths NodeZero autonomously tests production environments using real attack techniques within defined scope and safety controls. Its capabilities span internal and external infrastructure, cloud, and web applications, helping teams understand how exploitable weaknesses can lead to unauthorized access, privilege escalation, and exposure of sensitive data. Rather than treating each finding in isolation, NodeZero chains weaknesses to demonstrate attainable attacker impacts. Results include evidence of successful exploitation, documented attack paths, and prioritized remediation guidance, giving partners a clear basis for recommending what customers should address first. NodeZero WebApp extends this approach to custom, business-critical web applications. It supports authenticated testing to uncover exploitable application weaknesses, including broken access controls and business logic flaws, helping teams assess risks that scanning alone can miss. Business consulting services Building Services Around Measurable Outcomes Multi-tenant support, MSP-friendly licensing, and white-labeled reporting help partners manage testing across customers and incorporate findings into their own service offerings. Partners can build engagements around: * Autonomous penetration testing: Assess customer exposure through repeatable tests across infrastructure, identity, cloud, and web applications. * Prioritized remediation: Direct customer effort toward weaknesses that contribute to demonstrated attacker impacts. * Fix verification: Retest remediated weaknesses to determine whether the previously demonstrated exploitation remains possible. * Threat-focused assessments: Evaluate exposure to supported vulnerabilities in CISA's Known Exploited Vulnerabilities Catalog. * Ongoing security validation: Repeat testing after infrastructure changes, application releases, or control updates to identify new or recurring exposure. This service model gives MSPs a way to maintain an ongoing security conversation with customers. Each engagement can connect a demonstrated risk to a corrective action and a verified result, helping customers understand what their security investment accomplished and where further work is needed. The partnership expansion builds on Horizon3's regional investment, including its EMEA headquarters in Amsterdam, which supports customers, partners, and operations across the region.

Business Wire

Oct 13th, 2026

Horizon3 promotes Keith Poyser to EMEA general manager after 260% revenue growth

Horizon3 has promoted Keith Poyser to general manager for Europe, the Middle East and Africa (EMEA). He was previously vice president, EMEA, and will lead the next phase of the region's growth. The move follows more than 260% regional revenue growth in the last fiscal year and the opening of the security company's EMEA headquarters in Amsterdam. Since Poyser joined in September 2024, the EMEA team has grown from eight to more than 110 employees. "Keith has earned this role," said Snehal Antani, chief executive officer and co-founder of Horizon3. Poyser has more than 20 years of experience scaling technology businesses, including leadership roles at SentinelOne, Palo Alto Networks, and IBM. Horizon3 sells NodeZero, an autonomous security testing tool.

Crypto.com

Sep 15th, 2026

CrowdStrike (CRWD) stock: what's behind Tuesday's premarket dip.

CrowdStrike (CRWD) stock: what's behind Tuesday's premarket dip. News Tue, 15 Sep 2026 13:27:54 UTC 1 hour ago Tldr. * CRWD is down 1.73% to $231.31 in premarket trading Tuesday after a strong sector-wide rally Monday * The pullback is seen as routine profit-taking following a sharp cybersecurity rotation * Monday's rally was sparked by Anthropic CEO Dario Amodei calling for a voluntary slowdown in frontier AI model development * CrowdStrike reported ARR of $5.84 billion in Q2 FY27, up 25% year-over-year * Horizon3 announced a new integration between its NodeZero platform and CrowdStrike Falcon Next-Gen SIEM CrowdStrike (CRWD) pulled back slightly in premarket trading Tuesday, down 1.73% to $231.31, giving back a slice of Monday's gains as investors took some profits after a sector-wide surge. Monday's rally across cybersecurity was triggered by weekend comments from Anthropic CEO Dario Amodei, who called for a voluntary deceleration in frontier AI model development. Sam Altman and Elon Musk also backed the push. Amodei's key concern was that unchecked compute scaling creates serious cybersecurity vulnerabilities. That warning sent capital rotating out of hardware names and into enterprise security platforms. ... Continue reading the full article at the original source below. This content is automatically aggregated. Full credit goes to the original publisher (coincentral.com).

Horizon3.ai

Federal Senior Backend Engineer

About the job