Staff Engineer, Offensive Security

Who we are 

At Twilio, we’re shaping the future of communications, all from the comfort of our homes. We deliver innovative solutions to hundreds of thousands of businesses and empower millions of developers worldwide to craft personalized customer experiences.

Our dedication to remote-first work, and strong culture of connection and global inclusion means that no matter your location, you’re part of a vibrant team with diverse experiences making a global impact each day. As we continue to revolutionize how the world interacts, we’re acquiring new skills and experiences that make work feel truly rewarding. Your career at Twilio is in your hands.

We use Artificial Intelligence (AI) to help make our hiring process efficient. That said, every hiring decision is made by real Twilions!

.

See yourself at Twilio

Join the team as Staff Engineer, Offensive Security

About the job

The Staff Engineer acts as a Technical Lead. You don't just find bugs; you design complex attack chains that demonstrate systemic risk. You spend as much time writing custom code and researching new bypasses as you do executing tests.

Responsibilities

In this role, you will:

• Full-Stack Penetration Testing: Perform manual and automated testing of web applications, APIs, and mobile apps (iOS/Android).
• Internal/External Network Audits: Conduct network and cloud level assessments with various tooling
• Vulnerability Validation: Triage and validate reports from automated scanners or bug bounty hunters to eliminate false positives and escalate true positives
• AI/LLM Probing: Perform initial prompt injection and jailbreak tests on AI prototypes, services, and applications using established checklists (OWASP Top 10 for LLMs).
• Technical Reporting: Draft high-quality reports that detail the "path to compromise" with clear, reproducible steps for developers.
• Tool Maintenance: Manage and update the team's testing infrastructure (e.g., Burp Suite, and basic C2 listeners).
• Remediation Support: Provide direct technical guidance to engineering teams on how to patch vulnerabilities like XSS, SQLi, and IDOR.
• Adversary Emulation: Design and lead multi-week Red Team operations that mimic specific threat actors (APTs) to test the SIRT detection capabilities.
• Custom Exploit Development: Build custom payloads, droppers, and obfuscated scripts to bypass EDR/AV and maintain stealth.
• AI Red Teaming Architecture: Build automated testing frameworks for AI systems (e.g., using PyRIT, Promptfoo, or Garak) to test for models related to sensitive data leakage.
• Cloud & Infrastructure Attacks: Execute sophisticated attacks against AWS/Azure/K8s, focusing on IAM misconfigurations and container escapes.
• Purple Teaming: Collaborate with SIRT and Detection Engineering to tune SIEM alerts based on the techniques used during an engagement.
• Strategic Bug Bounty Management: Oversee the organization's bug bounty program, identifying trends in submissions to suggest broad architectural security changes.

Qualifications

Twilio values diverse experiences from all kinds of industries, and we encourage everyone who meets the required qualifications to apply. If your career is just starting or hasn't followed a traditional path, don't let that stop you from considering Twilio. We are always looking for people who will bring something new to the table!

Required:

• Experience: 7-10 years in offensive security, penetration testing, a high-volume bug bounty background, AppSec, or vulnerability exploitation, and track record of finding high/critical vulnerabilities in complex environments using pentesting commercial or custom tools.
• Concepts: Expert Knowledge and  solid understanding of the MITRE ATT&CK matrix and the OWASP Top 10 for web applications and top 10 for LLMs, post exploitation (lateral movement, persistence, data exfiltration) and Adversarial ML.
• Tooling: Proficient in OffSec popular tools like Burp Suite professional, Nmap, Metasploit, Wireshark etc... and AI security tools such as LangChain, TensorFlow for adversarial testing or, as well as use of C2 frameworks (Cobalt Strike, Sliver, Havoc) or similar tools
• Scripting and Coding: Ability to write functional scripts in Python or Bash to automate repetitive testing tasks and proficiency in coding and scripting like Python, C++, and scripting for creating custom offensive exploits that avoids signature-based detection.
• Certifications: Possession of advanced industry certifications such as OSCP, OSEP, OSWE, GXPN or similar training in OffSec tracks is highly desirable

Desired:

• Telecom expertise is preferred
• Excellent written and verbal communication skills.
• Ability to influence and build effective working relationships with all levels of the organization.
• Proficiency in multiple languages applicable to the region.

Location

This role will be Remote, and based in Ireland

Travel 

We prioritize connection and opportunities to build relationships with our customers and each other. For this role, approximately 15% travel is anticipated to help you connect in-person in a meaningful way.

What We Offer

Working at Twilio offers many benefits, including competitive pay, generous time off, ample parental and wellness leave, healthcare, a retirement savings program, and much more. Offerings vary by location.

Twilio thinks big. Do you?

We like to solve problems, take initiative, pitch in when needed, and are always up for trying new things. That's why we seek out colleagues who embody our values — something we call Twilio Magic. Additionally, we empower employees to build positive change in their communities by supporting their volunteering and donation efforts.

So, if you're ready to unleash your full potential, do your best work, and be the best version of yourself, apply now! If this role isn't what you're looking for, please consider other open positions.

Twilio is proud to be an equal opportunity employer. We do not discriminate based upon race, religion, color, national origin, sex (including pregnancy, childbirth, reproductive health decisions, or related medical conditions), sexual orientation, gender identity, gender expression, age, status as a protected veteran, status as an individual with a disability, genetic information, political views or activity, or other applicable legally protected characteristics. We also consider qualified applicants with criminal histories, consistent with applicable federal, state and local law. Qualified applicants with arrest or conviction records will be considered for employment in accordance with the Los Angeles County Fair Chance Ordinance for Employers and the California Fair Chance Act. Additionally, Twilio participates in the E-Verify program in certain locations, as required by law.