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Application Security Engineer

Whatnot
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Hybrid (Kraków (Poland) / Remote (US))Full-timePosted 1w ago

About the role

Role focused on protecting Whatnot’s web and mobile products by performing security reviews, threat modeling, and building reusable security tooling. Remote-friendly with Kraków hub proximity requirement for in-person collaboration.

Responsibilities

  • Perform security-focused code reviews, identifying vulnerabilities and recommending practical fixes.
  • Partner with product and engineering teams on threat modeling and application security reviews.
  • Help teams reproduce, triage, and address security vulnerabilities in web and mobile applications.
  • Support our bug bounty program by investigating reports and working with teams on remediation.
  • Support the preparation of security releases.
  • Help develop security patterns, processes, and automated tooling that prevent entire classes of security issues.

Qualifications

  • 5 years of relevant experience
  • Software development experience in Python, Elixir, or JavaScript
  • Ability to review code for security vulnerabilities and collaborate with engineers to implement fixes
  • Understanding of application security risks and threat modeling
  • Ability to investigate, reproduce, and triage web and mobile vulnerabilities
  • Strong communication and collaboration skills to explain security risks and recommendations
  • Practical problem-solving approach with interest in building reusable tools and processes

Skills

Required:Software developmentSecurity reviewsThreat modelingVulnerability triageCommunication
Last updated Oct 21, 2026. Interested? Apply on the company site.
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About Whatnot

Whatnot is the largest livestream shopping platform in the U.S.

Whatnot is the largest livestream shopping platform in the U.S., connecting buyers and sellers in real-time across any category – from collectibles like trading cards to comics, fashion, sneakers, and more.

marketplacee-commerce
Company profileWebsite

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