Security Engineer, Red Team

Whatnot; Seattle (WA); Remote; USD 210,000 - 290,000; Full time

Benefits offered by this job

Generous Holiday and Time off Policy

Health Insurance options including Med

Work From Home Support

Home office setup allowance

Monthly allowance for cell phone and

Internet

Care benefits - wellness monthly

Annual childcare allowance

Lifetime family planning benefit

401k with employer match up to 4%

Pension plans internationally

Dogfooding budget

Parental Leave - 16 weeks paid

Job summary

Whatnot is seeking a Red Team Engineer to identify and remediate security weaknesses across cloud, networks, and applications. You will build AI-assisted testing harnesses and agent workflows, using MITRE ATT&CK/ATLAS to simulate end-to-end attack paths and coordinate with purple/blue teams.

You’ll leverage Python tooling, drive offensive security across production-adjacent systems, and communicate findings clearly to engineers and executives alike.

Qualifications

• 3+ years in offensive security, red teaming, or penetration testing with real engagements against production-scale environments.
• You write your own tooling in Python rather than only running existing utilities.
• Hands-on experience building LLM-powered workflows or agents (tool use, orchestration, evaluation, guardrails).
• Deep knowledge of at least two areas: cloud security and IAM/identity attacks, Kubernetes or container escapes, web/API exploitation, CI/CD and supply chain attacks.
• Working knowledge of AI-specific risks: prompt injection, insecure tool use, data leakage, excessive agent permissions, model supply chain issues.
• Sound judgment on scope, safety, and blast radius; test production-adjacent systems without outages.
• Clear written communication: produce actionable reports for engineers and skimmable summaries for executives.

Responsibilities

• Plan and run authorized red team operations across cloud (AWS), Kubernetes, networks, and internal apps.
• Build and maintain AI-assisted testing harnesses and agent loops with logging and gates.
• Use AI tools to speed vulnerability research, payload and test-case generation, and code review.
• Emulate adversaries using MITRE ATT&CK and ATLAS to create end-to-end attack paths.
• Run purple team exercises with detection engineering and incident response; tune detections.
• Write clear findings with reproduction steps, impact, and fixes; track remediation and retest.
• Automate regression tests to keep fixes in place and feed results into CI/CD.
• Share techniques and lessons learned with engineering teams; collaborate with Blue Team.

Skills

Python programming

Offensive security

Red teaming

LLM-powered workflows

Clear written communication

Job description

Join the Future of Commerce with Whatnot!

Whatnot is the largest live shopping platform in North America and Europe to buy, sell, and discover the things you love. Whether it's trading cards, fashion, electronics, or live plants, our sellers are building real businesses across hundreds of categories. We're building live commerce at a scale that's never been done in the West, and there's no playbook to copy. The people here are shaping how an entirely new industry develops.

As a remote co-located team, we're inspired by our values and anchored in hubs across the US, UK, Ireland, Poland, Germany, and Australia. We move fast, stay close to our users, and focus on the work that drives the most impact.

We're one of the fastest growing marketplaces and were recently named the #1 Best Startup Employer in America by Forbes. Check out the latest Whatnot updates on our news and engineering blogs and join us as we enable anyone to turn their passion into a business and bring people together through commerce.

Role

• Plan and run authorized red team operations across cloud (AWS), Kubernetes, networks, identity systems, SaaS, and internal applications, under written rules of engagement.
• Build and maintain AI-assisted testing harnesses: agent loops that run recon, attack-path discovery, fuzzing, and exploit validation with logging, scoping controls, and human approval gates.
• Use LLMs and agentic tools to speed up vulnerability research, payload and test‑case generation, code review, and report drafting, and measure where they help and where they mislead.
• Red team our own AI systems: prompt injection, tool and connector abuse, data exfiltration, model and agent permission boundaries, and supply chain risk in AI dependencies.
• Emulate realistic adversaries using MITRE ATT&CK and ATLAS, chaining findings into end‑to‑end attack paths rather than isolated bugs.
• Run purple team exercises with detection engineering and incident response, and tune detections based on what your tests evade.
• Write clear findings with reproduction steps, impact, and recommended fixes; track remediation to closure and retest.
• Automate regression tests so fixed weaknesses stay fixed, and feed results into CI/CD pipelines.
• Document and share techniques, tooling, and lessons learned with engineering teams.
• Work collaboratively with Whatnot’s Blue Team on Purple Team engagements to help strengthen Whatnot’s overall security posture.

You

Curious about who thrives at Whatnot? We’ve found that low ego, a growth mindset, and leaning into action and high impact goes a long way here.

As our next Red Team Engineer you’ll find weaknesses in our infrastructure before real attackers do. You will use AI tools and agents to scale offensive testing, build the harnesses that run it, and turn findings into fixes across cloud, network, application, identity and CI/CD layers.

• 3+ years in offensive security, red teaming, or penetration testing, with real engagements against production‑scale environments.
• Strong programming skills in Python; you write your own tooling instead of only running others.
• Hands‑on experience building LLM‑powered workflows or agents (tool use, orchestration, evaluation, guardrails), not just prompting a chat window.
• Deep knowledge of at least two areas: cloud security and IAM abuse, Active Directory or identity attacks, Kubernetes and container escapes, web and API exploitation, CI/CD and supply chain attacks.
• Working knowledge of AI‑specific risks: prompt injection, insecure tool use, data leakage, excessive agent permissions, and model supply chain issues.
• Sound judgment on scope, safety, and blast radius; you know how to test production‑adjacent systems without causing outages.
• Clear written communication: reports an engineer can act on and an executive can skim.

Benefits

• Generous Holiday and Time off Policy
• Health Insurance options including Medical, Dental, Vision
• Work From Home Support
• Home office setup allowance
• Monthly allowance for cell phone and internet
• Care benefits
• Monthly allowance for wellness
• Annual allowance towards Childcare
• Lifetime benefit for family planning, such as adoption or fertility expenses
• Retirement; 401k offering for Traditional and Roth accounts in the US (employer match up to 4% of base salary) and Pension plans internationally
• Monthly allowance to dogfood the app
• All Whatnauts are expected to develop a deep understanding of our product. We're passionate about building the best user experience, and all employees are expected to use Whatnot as both a buyer and a seller as part of their job (our dogfooding budget makes this fun and easy!).
• Parental Leave
• 16 weeks of paid parental leave + one month gradual return to work *company leave allowances run concurrently with country leave requirements which take precedence.

Please note: Whatnot will only contact you through official @whatnot.com email addresses. If you see an email impersonating a Whatnot recruiter, please disregard and report it as spam.

EOE

Whatnot is proud to be an Equal Opportunity Employer. We value diversity, and we do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, parental status, disability status, or any other status protected by local law. We believe that our work is better and our company culture is improved when we encourage, support, and respect the different skills and experiences represented within our workforce.

Compensation Range: $210K - $290K