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Josh Tillery
@fas_guardian
AI Security Specialist and Infrastructure Engineer
United States
English
About me
Founder of Fallen Angel Systems. I built Guardian (AI defense - prompt injection scanner) and Judgement (AI offense - red team attack console). Active bug bounty hunter with submissions to Microsoft MSRC and HackerOne.
I specialize in AI security, Python/FastAPI backends, ML pipelines, and Linux infrastructure. Published red team research on Claude, GPT-4o, and Sonnet model security.
I don't just run tools and hand you a report. I understand the attacks because I built the defenses.
Skills
Josh Tillery
Offline •
Average response time: 2 hours
See my services
API & Integrations
I will build a rest API using python fastapi with database and auth
AI Technology Consulting
I will test your ai application for security vulnerabilities
Portfolio
Work experience
Founder / Lead Developer
Fallen Angel Systems • Self-employed
May 2025 - Present • 1 yr
Built FAS Guardian, an AI security platform that detects prompt injection attacks. Developed a multi-layer scanning engine (ML models + pattern matching) serving production API customers. Manage full stack from model training to VPS deployment.
Sys Admin
computershare • Full-time
Aug 2020 - Jun 2025 • 4 yrs 10 mos
Installing, configuring, and maintaining server hardware and software, managing virtual machines, and ensuring network connectivity. Managing Active Directory/user accounts, setting permissions, implementing firewalls, applying patches, and conducting security audits. Using scripts to automate repetitive tasks and documenting system configurations. Managing email, file storage, and web services.
Backend developer
Google • Full-time
May 2011 - May 2020 • 9 yrs
Python (FastAPI), PostgreSQL/SQLite REST API design, Cloudflare, DNS, tunnels, security Webhooks Linux, also used Python, JavaScript/Node.js, SQL, Bash
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velbix
Canada
Josh is a professional who takes into consideration all tiny details. He discusses with you implementation details to the point and proactively recommends better and more optimized approaches. Happy to work with him.
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