Staff Software Engineer

Who We Are We’re on a mission to stop the most dominant cyberattacks on the planet. Cybersecurity titans are born when a new attack vector overwhelms existing defenses. When ransomware ran rampant, CrowdStrike emerged as the category leader for securing user endpoints. Today, AI has made account compromise the #1 cybercrime. LLM-powered phishing messages get past email security, allowing attackers to compromise accounts and exfiltrate sensitive data in minutes. Incumbents can’t keep up. They catch these attacks late, or miss them altogether. Enter Petra, security for when no perimeter remains. We are building an AI-driven Detection and Response platform to catch and remove attackers before they can act. We’ve grown very quickly, reaching mid-7-figures in ARR in under a year — we now protect over 1.6 million users across 10,000+ businesses. We win 90%+ of head-to-heads. We price premium, yet have extremely low customer churn. Our customers consistently tell us that Petra is the best product they’ve ever used. You can see a demo here. This is a rare chance to join early and help scale to $20M+ in revenue in the next 12 months. Our founders are YC W24, ex-Abnormal Security, Palo Alto Networks, and Bridgewater. What You’ll Do Ownership is everything here. You’ll have deep knowledge across the stack and own large parts of the platform — from our AI detection pipeline to the product surfaces that MSPs and security teams rely on every day. Petra is a premium product and it’s everyone’s job to make sure it stays that way. That means you won’t just write code — you’ll talk to customers, map their workflows, find their time-sinks, and think creatively about how to make the product increasingly excellent. Concretely, you will: Build and evolve our detection platform. Working closely with our founding team, you’ll help design and build the systems that identify account compromise in real time — spanning signal ingestion, behavioral analysis, and AI-powered decisioning. Drive product quality end to end. Take problems from raw customer insight through to shipped, production features. You care about the full loop, not just your slice. Architect for scale. We’re growing fast. Make calls that let us move quickly today without incurring debt that bites us at 10x the user base. Raise the technical bar. As a senior voice on a lean team, your instincts and opinions shape how we build. You’ll establish patterns, push for correctness, and raise the quality of everything around you. Our stack is Node, TypeScript, React, and Python… for now. Who You Are 3+ years of software engineering experience , with meaningful time in production systems at scale. Deep full-stack fluency — comfortable owning a feature from data model to UI, with strong opinions about where to draw the lines. Experience building data-intensive or real-time systems . Bonus if you’ve worked on security, fraud detection, or anomaly detection pipelines. Strong ML/AI integration experience — you’ve shipped systems that use models in production, not just experimented with them. High agency and high output . You don’t wait for a spec — you identify the problem, propose the solution, and execute. You ship fast, find the 90/10, and don’t let perfect be the enemy of done. Sharp and scrappy. You learn fast, ask the right questions, and figure it out — whether that’s a technical tradeoff, the right abstraction, or the right shortcut. Comfortable in a small-team, high-autonomy environment . The scope of your work is rarely handed to you, and you wouldn’t have it any other way. Proud of your craft. You care about building things that work well and hold up over time. Benefits and Pay: Competitive salary — we pay top dollar for exceptional engineers Equity Fully covered healthcare, dental, vision Lunch, dinner, and snacks at the office Relocation support This role is in-person, here in SF. #J-18808-Ljbffr Petra Security