Senior Application Security Engineer
@ Unit21

Hybrid
$165,000
Hybrid
Full Time
Posted 18 hours ago

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Job Details

About Unit21

Unit21 protects businesses against adversaries engaging in money laundering, fraud, and other sophisticated risks by offering a no-code toolset to model, detect, and remediate suspicious activity. Backed by investments from Google, Tiger Global, ICONIQ, Diane Greene, Jack Dorsey, and others, Unit21 is a rapidly growing Series C startup.

About the Role

As a Senior Application Security Engineer, you will be a hands-on builder responsible for protecting our platform, customers, and their data. This is a technical role focused on designing and implementing security systems in the code, owning critical security infrastructure, and building automations to mitigate vulnerabilities.

What You'll Be Doing

  • Design, code, and deploy automated security controls and frameworks.
  • Build, own, and operate tools for our application security program (SAST, DAST, SCA, secret scanning).
  • Perform threat modeling, security architecture reviews, and in-depth code reviews (Python/TypeScript).
  • Conduct penetration tests and vulnerability assessments on web applications and APIs.
  • Develop custom tools and automation to enhance detection and response capabilities.
  • Act as a key member of the incident response team during security events.
  • Mentor and educate product engineers on secure coding best practices.

What We're Looking For

  • 4+ years of hands-on experience in software engineering or application security.
  • Expert-level proficiency in Python, with additional experience in Go or TypeScript a plus.
  • Deep understanding of common application vulnerabilities and mitigation techniques.
  • Proven experience integrating and operating security tools within developer workflows.
  • Experience in manual penetration testing and vulnerability assessments.
  • Hands-on experience in securing public cloud environments (AWS or GCP) and familiarity with IaC and containerization.

Compensation & Benefits

Competitive salary with a base pay range of $155,000 to $175,000 annually, pre-IPO stock options, 100% company-paid medical, dental, vision for employees, alongside numerous other benefits including unlimited paid time off, 401(k), learning stipends, and more. Enjoy great office space in the San Francisco Financial District with catered meals and team events.

Key Skills/Competency

  • Application Security
  • Automation
  • Penetration Testing
  • Threat Modeling
  • Code Review
  • Python
  • TypeScript
  • Cloud Security
  • Infrastructure as Code
  • Containerization

How to Get Hired at Unit21

🎯 Tips for Getting Hired

  • Research Unit21's culture: Understand their mission, values, and growth story.
  • Customize your resume: Emphasize hands-on security and coding expertise.
  • Highlight technical skills: Showcase Python, TypeScript, and automation experience.
  • Prepare for interviews: Review threat modeling and penetration testing cases.

📝 Interview Preparation Advice

Technical Preparation

Review Python and TypeScript security libraries.
Study AWS/GCP security configurations and best practices.
Practice SAST, DAST, and SCA tool integrations.
Refresh penetration testing and threat modeling techniques.

Behavioral Questions

Describe a challenging security project you led.
Explain how you handle cross-team technical conflicts.
Share a time you mentored a colleague effectively.
Discuss managing priorities under security incidents.

Frequently Asked Questions