Application Guide

How to Apply for Senior Security Engineer

at Lime

🏢 About Lime

Lime is a leader in micro-mobility, offering shared electric scooters and bikes to reduce urban congestion and carbon emissions. As a remote-first company with a mission to build a future where transportation is shared, affordable, and carbon-free, Lime offers a dynamic environment where security directly impacts millions of riders and city partnerships.

About This Role

As a Senior Security Engineer, you'll embed security into Lime's product development lifecycle, from threat modeling new features to automating security testing for mobile apps and cloud services. Your work will protect rider data, ensure regulatory compliance, and enable rapid innovation across Lime's global fleet.

💡 A Day in the Life

Start by reviewing new feature designs from product teams, then threat model a proposed API change. Mid-morning, triage bug bounty submissions and prioritize fixes with engineering. Afternoon, update CI/CD pipelines for a new mobile app version, then join a cross-team incident response drill for a simulated data exposure.

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Interview Prep

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🎯 Who Lime Is Looking For

  • Has 5+ years in product/application security with deep expertise in mobile (iOS/Android) and API security, including OAuth, JWT, and mobile app reverse engineering.
  • Can build and maintain automated security pipelines (SAST, DAST, SCA) in CI/CD, with hands-on experience in AWS/GCP security services (e.g., GuardDuty, Security Hub).
  • Thrives in a fast-paced, remote startup environment, able to translate technical risks into clear guidance for product teams and non-technical stakeholders.
  • Has experience running bug bounty programs (e.g., HackerOne) and participating in incident response, with a proactive mindset for detection engineering.

📝 Tips for Applying to Lime

1

Highlight specific mobile security projects you've led (e.g., securing a ride-hailing app, implementing certificate pinning).

2

Quantify impact: mention vulnerabilities found, reduction in critical bugs, or automation coverage improvements (e.g., 'Reduced mean time to detection by 40%').

3

Tailor your resume to show cloud security skills (AWS/GCP) and experience with Terraform or similar IaC tools.

4

Include a brief note on how you've collaborated with remote engineering teams—Lime is fully remote.

5

Mention any experience with micro-mobility, IoT, or location-based services to show industry alignment.

✉️ What to Emphasize in Your Cover Letter

["Emphasize your passion for sustainable urban transportation and how security enables Lime's mission.", 'Describe a specific instance where you automated security testing in CI/CD, reducing manual effort.', 'Show understanding of mobile security challenges unique to shared devices and GPS tracking.', 'Mention experience with bug bounty programs and how you balanced openness with risk.']

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🔍 Research Before Applying

To stand out, make sure you've researched:

  • → Read Lime's blog posts on security and engineering to understand their tech stack and culture.
  • → Review their public bug bounty program on HackerOne to see past vulnerabilities and scope.
  • → Understand local regulations for shared e-scooters in key markets (e.g., GDPR, CCPA, city data-sharing rules).
  • → Check LinkedIn for current security engineers to gauge team size and background.

💬 Prepare for These Interview Topics

Based on this role, you may be asked about:

1 Threat model a new feature: e.g., a scooter unlock via QR code—walk through risks and mitigations.
2 Design a secure API for fleet management: authentication, rate limiting, data validation.
3 How would you automate dependency scanning for a mobile app with frequent releases?
4 Incident response scenario: a rider data breach via an API vulnerability—your steps.
5 Explain a time you convinced a product team to delay a feature for security—how you communicated risk.
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⚠️ Common Mistakes to Avoid

  • Focusing only on web security without demonstrating mobile or API security expertise.
  • Ignoring the remote aspect—failing to show experience with async communication or self-management.
  • Being too generic: not connecting your experience to Lime's specific products (scooters, bikes, IoT).

📅 Application Timeline

This position is open until filled. However, we recommend applying as soon as possible as roles at mission-driven organizations tend to fill quickly.

Typical hiring timeline:

1

Application Review

1-2 weeks

2

Initial Screening

Phone call or written assessment

3

Interviews

1-2 rounds, usually virtual

✓

Offer

Congratulations!

Ready to Apply?

Good luck with your application to Lime!

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