We Open-Sourced Our Prompt Defense Scanner: 200 Lines of Regex That Replace an LLM

📰 Dev.to · ppcvote

Learn how to use a deterministic prompt defense scanner built with regex to replace LLMs for security checks, and why regex is better suited for this task

intermediate Published 24 Apr 2026
Action Steps
  1. Build a prompt defense scanner using regex to detect 12 attack vectors
  2. Run the scanner on your LLM inputs to identify potential security threats
  3. Configure the regex patterns to customize the scanner for your specific use case
  4. Test the scanner's performance and accuracy using sample inputs
  5. Apply the scanner to your production environment to enhance security
Who Needs to Know This

Security teams and developers can benefit from using this scanner to protect against LLM-based attacks, and understand the advantages of using regex over LLMs

Key Insight

💡 Regex can be more effective than LLMs for prompt defense due to its deterministic nature and zero cost

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🚀 Replace LLMs with regex for prompt defense! Learn how to build a deterministic scanner in 200 lines of code 🚀
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