---
title: 'Security Software Engineer at RunSybil'
canonical: 'https://feeny.ai/job/security-software-engineer-runsybil-united-states-1pj8gsxey1nz'
type: 'job'
last_seen: '2026-09-08'
---

# Security Software Engineer at RunSybil

- **Company:** RunSybil
- **Location:** United States
- **Employment:** full-time
- **Work type:** remote
- **Posted:** 2026-06-22
- **Last confirmed live:** 2026-09-08
- **Apply:** https://jobs.ashbyhq.com/runsybil-jobs/43bfadc7-0346-40e0-81ff-f2b1bacaf49f

## Job description

## About RunSybil

Founded in 2023 by Ari Herbert-Voss and Vlad Ionescu, RunSybil is on a mission to automate hacker intuition. We’re building Sybil: an AI-driven pentester that discovers vulnerabilities before they’re exploited. As adversaries adopt AI to increase their attack surface, we’re putting cutting-edge offensive security into the hands of defenders. Backed by strong investor support and early customer traction, our team is composed of experts from OpenAI, Meta, Mandiant, Palantir, Cruise, Trail of Bits, and Aptiv.

## About the Role

We are looking for a Security Software Engineer who ships. You will own the research and development of offensive capabilities that power Sybil, working end-to-end from vulnerability discovery through production delivery. This is a role for someone who finds their own problems, builds their own solutions, and raises the bar for everyone around them.

You will work closely with our engineering and product teams to translate offensive security intuition into repeatable, AI-driven capabilities. If you thrive in ambiguity, move fast, and want your work to have a direct impact on a product customers rely on, this is the role for you.

## What You Will Do

- Research and develop offensive agentic capabilities that become core Sybil features
- Hunt for real vulnerabilities across a range of target environments and translate what you find into repeatable, automated techniques
- Build and ship end-to-end customer-facing features: from research spike to production deployment
- Design and implement LLM-powered tooling that extends Sybil's reach and depth across attack surfaces
- Identify gaps in our offensive coverage and propose technical initiatives to close them, without waiting to be asked
- Contribute to technical design discussions, review your teammates' work, and hold a high bar for what we ship
- Operate with ownership: you define the problem, build the solution, and see it through

We’re looking for someone who brings:

- 4 or more years of software engineering experience, with meaningful time in offensive security contexts
- Hands-on experience finding vulnerabilities across a variety of targets, whether through red teaming, bug bounty, CTF, or production pentesting
- Strong Python fundamentals: you have designed, deployed, and maintained backend systems in production
- Comfort with modern JavaScript and React; you can own a feature across the full stack
- Experience building with LLMs or generative AI tools, including prompt engineering and integrating model outputs into real workflows
- A builder's instinct: you default to figuring things out, not waiting for direction
- Familiarity with DevOps and infrastructure concepts; you can own your own deployment pipeline
- Strong written communication; you can explain a vulnerability, a design decision, or a tradeoff clearly

Location: United States (Remote)

Salary: The base salary for this full-time position ranges from $170,000 - $210,000. In addition to base salary, we offer meaningful equity. We want everyone here to have ownership in what we're building.

Diverse teams build better products. RunSybil is committed to hiring people who bring different perspectives, lived experiences, and backgrounds to our work. We encourage candidates of all races, ethnicities, gender identity and expression, sexual orientation, disability or medical conditions, ages, religions, and socioeconomic backgrounds to apply. Pursuant to the San Francisco Fair Chance Ordinance, we will consider for employment qualified applicants with arrest and conviction records. If you're excited about this role but don't check every box, we still want to hear from you.

## About RunSybil

## Core Business
- **Primary industry**: Computer and Network Security / Offensive Security (AI-powered penetration testing)
- **Target customers**: Enterprise B2B – security teams at high-risk, multi-tenant, or rapidly deploying organizations
- **Mission**: “Automate hacker intuition” – replace periodic pentests and bug bounties with continuous, AI-driven validation of exploitable vulnerabilities.

## Products & Services
- **Sybil Platform**: An AI agent that continuously tests applications and infrastructure by reasoning like an elite human attacker. It chains vulnerabilities across code, APIs, cloud, and infra to surface only real, exploitable paths. Deployed on every deployment, it provides feedback on pull requests and enables Continuous Threat Exposure Management (CTEM) validation.

## Market Standing
- **Valuation/Market Cap**: Not disclosed
- **Key Metric**: Total funding – $40M (Seed round, March 2026)
- **Notable Investors/Partners**: Lead investor Khosla Ventures; 8 total investors in the seed round
- **Growth Signals**: Headcount grew 185.7% YoY to ~10 employees; monthly LinkedIn follower growth of +8.0% and yearly +285.8%; recent $40M raise signals strong investor confidence.

## Competitive Advantages
- **AI-native reasoning**: Sybil doesn't scan for signatures – it reasons like a human attacker, chaining multi-layer vulnerabilities and validating exploitability.
- **Continuous, context-aware testing**: Re-evaluates the attack surface on every deployment, adapting to changes rather than running periodic generic checks.
- **Reduced false positives**: Claims 90% fewer false positives by proving actual exploitability, eliminating triage burden.
- **Team pedigree**: Founders and early team hail from OpenAI, Meta, Mandiant, NCC Group, and Trail of Bits – combining frontier AI research with elite red-team experience.

## Strategic Focus
- Scaling the engineering and go-to-market teams to expand the platform’s coverage and customer adoption.
- Replacing traditional bug bounties and point-in-time pentests with continuous, AI-driven offensive security.
- Building a “company-survival mindset” and prioritizing velocity, shipping, and quality of thinking.

## Why Work Here
- **Culture**: “Built by researchers. Driven by conviction.” Emphasis on shipping fast, thinking like an attacker, preempting what’s next, and engineering craft.
- **Work model**: Hybrid with hubs in San Francisco and New York City; remote or hybrid options available.
- **Benefits**: Comprehensive medical/dental/vision (100% employee, 80–85% dependents), unlimited PTO (20-day suggested minimum), 12 weeks paid parental leave, 401(k) with 3% auto-enrollment, mental health and wellness support, commuter benefits, company-provided laptop, regular team onsites.
- **Team**: Small, high-caliber group (ex-OpenAI, Meta, Mandiant, NCC Group, Trail of Bits) working on the leading edge of AI and security. Interview process is structured, collaborative, and fast – LLM use encouraged.

## Sources
1. [runsybil.com](https://www.runsybil.com/)
2. [runsybil.com/company](https://www.runsybil.com/company)
3. [runsybil.com/careers](https://www.runsybil.com/careers)
4. [builtin.com](https://builtin.com/company/runsybil)
5. [linkedin.com](https://www.linkedin.com/company/runsybil)

## Other roles at RunSybil

- [Security Analyst](https://feeny.ai/job/security-analyst-runsybil-united-states-g531z30tq8y7) — United States
- [Software Engineer I](https://feeny.ai/job/software-engineer-i-runsybil-new-york-k0thqp47baj5) — New York, NY
- [Forward Deployed Engineer](https://feeny.ai/job/forward-deployed-engineer-runsybil-united-states-z6x7c0j9xtj8) — United States
- [Sales Development Manager](https://feeny.ai/job/sales-development-manager-runsybil-san-francisco-dwexshbs2sca) — San Francisco, CA
- [Senior Account Executive, Technology](https://feeny.ai/job/senior-account-executive-technology-runsybil-san-francisco-ptqhwq1mrems) — San Francisco, CA
- [Product Software Engineer](https://feeny.ai/job/product-software-engineer-runsybil-united-states-kdfnge6zpsev) — United States
- [SRE/Infrastructure Engineer](https://feeny.ai/job/sre-infrastructure-engineer-runsybil-new-york-j7k1tddtxe0v) — New York, NY
- [Machine Learning Engineer](https://feeny.ai/job/machine-learning-engineer-runsybil-san-francisco-4gn81en20jpw) — San Francisco, CA / New York, NY
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