CloakLLM: Open Source Middleware for Protecting PII in LLM Prompts
infrastructure#llm📝 Blog|Analyzed: Mar 24, 2026 09:30•
Published: Mar 24, 2026 09:08
•1 min read
•Zenn LLMAnalysis
CloakLLM is an incredibly valuable open-source tool, offering robust protection for sensitive data within Large Language Model (LLM) prompts. Its ability to detect and replace Personally Identifiable Information (PII), including Japanese My Number, is a major step forward for data privacy. This middleware’s ease of integration with a single line of code makes it a compelling solution for developers.
Key Takeaways
- •CloakLLM is open-source, promoting community collaboration and transparency.
- •It provides Japanese-specific PII detection, including My Number, phone numbers, and passport data.
- •The middleware uses a 3-pass detection pipeline including regex and spaCy NER for robust protection.
Reference / Citation
View Original"CloakLLM is open-source middleware that detects PII, replaces it with reversible tokens, and restores originals in the response."