I will test your ai application for security vulnerabilities

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Josh Tillery

About this gig

Is your AI app vulnerable to prompt injection? Most are, and most teams don't know until it's too late. I'm the founder of Fallen Angel Systems, where I built Guardian, a production AI security scanner. I don't just run automated tools. I understand how these attacks work because I built the defenses against them. What I test for:


  • Direct prompt injection (jailbreaks, safety bypasses)
  • Indirect injection (hidden instructions in external data)
  • Context manipulation and role hijacking
  • Encoding tricks (base64, unicode, multilingual attacks)
  • Data exfiltration through crafted prompts
  • Privilege escalation and system prompt extraction


What you get:

  • Every attack payload is tested, with pass/fail results
  • Severity ratings for each vulnerability found
  • Clear, actionable fix recommendations
  • A report you can hand to your dev team


I've tested thousands of attack patterns against real AI applications. If your app has a weakness, I'll find it. Works with any LLM-powered app: chatbots, AI agents, RAG pipelines, customer support bots, or custom GPTs. Message me with details about your app, and I'll let you know how I can help.

Get to know Josh Tillery

Josh Tillery

AI Security Specialist and Infrastructure Engineer

5.0(1)
  • FromUnited States
  • Member sinceFeb 2026
  • Avg. response time2 hours
  • Last delivery1 month
  • Languages

    English
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.

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