---
title: 'Software Engineer I at RunSybil'
canonical: 'https://feeny.ai/job/software-engineer-i-runsybil-new-york-k0thqp47baj5'
type: 'job'
last_seen: '2026-09-08'
---

# Software Engineer I at RunSybil

- **Company:** RunSybil
- **Location:** New York, NY
- **Employment:** full-time
- **Work type:** hybrid
- **Posted:** 2026-07-27
- **Last confirmed live:** 2026-09-08
- **Apply:** https://jobs.ashbyhq.com/runsybil-jobs/fd733ce7-7892-4019-9f6d-b6a75ba2aa59

## 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 Software Engineer I who wants to do the best work of their first years anywhere. You will ship customer-facing features from your first weeks, build the agentic systems that power Sybil, and work directly alongside senior engineers and our founders every day. On a team this small, your code goes to production and customers use it. There is no shadow work here.

This is a role for someone who builds because they want to. The strongest people we know at this stage have a trail of side projects, open source contributions, and things they taught themselves because a problem got under their skin. If that sounds like you, we will give you real ownership, fast feedback, and problems worth growing into.

## What You'll Do

- Ship customer-facing features end to end, from first commit through production, with close review and support from senior engineers
- Build and extend the agentic systems behind Sybil, working primarily in Python with TypeScript and React across the stack
- Use LLMs as a core part of how you work: prompting, evaluating generated code, and building tooling that makes the whole team faster
- Own small projects yourself, including scoping the problem, proposing the approach, and seeing it through to done
- Debug real issues in a production system that customers rely on, and learn how long-running agentic workloads behave in the wild
- Contribute to technical design discussions and code reviews, and speak up when you see a better way
- Learn offensive security on the job from a team that includes some of the best in the field

We're Looking For Someone Who Has A Mix of The Following

- Strong Python fundamentals and real comfort with data structures; you write clean, working code and can explain every line of it
- Evidence of shipping software in any setting: internships, team or class projects, research, or personal projects all count equally
- A habit of initiative: times you took on more than the assignment asked, fixed the thing nobody owned, or taught yourself what the work needed
- Hands-on experience coding with LLMs, and judgment about when to use them, how to validate their output, and when to just write the code yourself
- Fast, honest communication; you say what you know, what you do not, and where you are stuck
- Coachability: you take a hint, run with it, and carry the lesson forward
- Familiarity with modern JavaScript and React is a plus

Location: NYC (Hybrid)

Salary: The base salary for this full-time position ranges from $135,000 - $165,000. 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)

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