Staff Security Engineer, Application Security

About fomo

fomo is growing fast, now serving 2M+ users and backed by a $75M Series B (Index Ventures, with Union Square Ventures and Benchmark) at a $550M valuation. As we scale, we're investing in a security function that can keep pace with an increasingly complex product surface without slowing down engineering velocity.

About the role

We're hiring a Staff Security Engineer to own and elevate our application security program. This is a hands-on, high-leverage role for someone who wants to be the technical authority on how we build secure software, not just someone who reviews tickets after the fact. You'll work directly with the engineering team to find and fix vulnerabilities, build tooling that scales security across the org, and shape how fomo thinks about security at the architecture and code level.

This role skews heavily toward product and application security. You won't be spending your time on corporate IT, endpoint management, or employee-facing security operations. Instead, you'll be embedded in how our product is designed, built, and shipped.

What you'll do

• Lead security architecture reviews and threat modeling for new features and major system changes, partnering directly with engineering and product teams from design through launch

• Own our secure SDLC program: static and dynamic analysis (SAST/DAST), dependency and software composition analysis, secrets scanning, and CI/CD security gates

• Perform deep-dive code reviews and manual penetration testing of high-risk services, APIs, and web applications

• Design and build internal security tooling and guardrails that let engineers move fast without introducing risk

• Run and mature our vulnerability management program, including triage, severity scoring, and driving remediation with engineering owners

• Manage relationships with external pentest vendors and bug bounty programs, and turn findings into durable fixes rather than one-off patches

• Set technical direction on authentication, authorization, API security, and data protection patterns used across the product

• Mentor engineers on secure coding practices and act as a go-to resource for security questions across the org

• Contribute to incident response when application-layer issues arise

• Help define and evolve fomo's overall AppSec roadmap and metrics

What we're looking for

• 7+ years in security engineering, with a substantial and recent focus on application security (not primarily corporate/IT security)

• Deep hands-on experience with secure code review, threat modeling, and common vulnerability classes (OWASP Top 10, auth/session flaws, SSRF, injection, business logic flaws, etc.)

• Strong software engineering background; comfortable reading and writing production code, not just running scanners

• Experience building and scaling AppSec tooling and processes (SAST/DAST, SCA, CI/CD security integration) at a growing company

• Track record of driving security into engineering culture through influence, not just gatekeeping

• Familiarity with cloud-native environments (AWS/GCP/Azure), container security, and modern API architectures

• Excellent communication skills; able to explain risk to both engineers and non-technical stakeholders

• Prior experience as a technical lead or staff-level IC who can operate with high autonomy

Nice to have:

• Experience with bug bounty program management

• Background in a high-growth consumer or marketplace product

Why fomo

You'll be the first dedicated AppSec hire shaping the security foundation of a company at real scale, with the autonomy to set standards rather than inherit them.