About Us
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ZeroDay Sentinel is a specialist offensive security firm. We think like attackers so your organisation can defend like defenders.
Our Mission
Making security accessible to every organisation
We started ZeroDay Sentinel because we kept seeing the same pattern: breaches that were entirely preventable, organisations that had never been tested, and security reports so dense with jargon they collected dust on a shelf.
Our mission is straightforward — find real vulnerabilities, explain them clearly, and help you fix them properly. Every engagement ends with your team in a stronger position than when we started.
We work with startups, scale-ups, and enterprises across fintech, healthcare, e-commerce, and SaaS — adapting our approach to what actually matters for your business context.
What Drives Us
Our Core Values
Integrity First
We operate with strict rules of engagement. Every test is authorised, every exploit is documented, and every finding is disclosed responsibly to our clients.
Continuous Research
Security is an arms race. Our team dedicates time to vulnerability research, CTF competitions, and bug bounty to stay ahead of emerging attack techniques.
Clear Communication
Technical depth should never sacrifice clarity. We translate complex findings into language that developers, managers, and executives can all act on.
Partnership Mindset
We measure success not by the number of vulnerabilities found, but by how much more secure your organisation is after every engagement.
The Team
The People Behind the Findings
Senior security researchers with real-world offensive backgrounds — not just certifications.
Alex Rivera
Lead Penetration Tester
8 years in offensive security. Former financial sector red-teamer. OSCP, CRTO certified.
Sara Kim
API & Web Security Specialist
Top 5% on HackerOne. Specialises in OWASP API Top 10 and business logic flaws.
Marcus Johnson
Cloud & Infrastructure Security
Former cloud engineer turned security researcher. AWS & GCP security specialist.