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What is PasteGuard?

PasteGuard is an OpenAI-compatible proxy that protects personal data and secrets before sending to your LLM provider (OpenAI, Azure, etc.).

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The Problem

When using LLM APIs, every prompt is sent to external servers - including customer names, emails, and sensitive business data. Many organizations have policies against sending PII to third-party AI services.

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The Solution

PasteGuard sits between your app and the LLM API: 
Your App → PasteGuard → LLM API
Two privacy modes:
ModeHow it works
MaskReplace PII with placeholders, send to provider, restore in response
RoutePII requests stay on your local LLM (Ollama, vLLM, llama.cpp), others go to your configured provider

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Quick Example

1

You send a prompt

Write a follow-up email to Dr. Sarah Chen (sarah.chen@hospital.org)
2

PasteGuard masks PII

Detected: Dr. Sarah Chen → <PERSON_1>, sarah.chen@hospital.org → <EMAIL_ADDRESS_1>
3

OpenAI receives

Write a follow-up email to <PERSON_1> (<EMAIL_ADDRESS_1>)
4

You get the response (unmasked)

Dear Dr. Sarah Chen, Following up on our discussion...
The LLM never sees the real data. PII is masked before sending and restored in the response.

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Features

  • PII Detection — Names, emails, phone numbers, credit cards, IBANs, and more
  • Secrets Detection — API keys, tokens, private keys caught before they reach the LLM
  • Streaming Support — Real-time unmasking as tokens arrive
  • 24 Languages — Works in English, German, French, and 21 more
  • OpenAI-Compatible — Change one URL, keep your code
  • Self-Hosted — Your servers, your data stays yours
  • Open Source — Apache 2.0 license, full transparency
  • Dashboard — See every protected request in real-time

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Next Steps

Quickstart

Get running in 2 minutes

Mask Mode

Replace PII with placeholders

Route Mode

Route PII to local LLM

Configuration

Customize your setup