noxway/privacy-guard-proxy repository overview

⁠privacy-guard-proxy

privacy-guard-proxy is a local reverse proxy for Claude Code⁠ that masks sensitive data before it leaves your machine.

Email addresses, names, IBANs, API keys, IDs, addresses, and other secrets are replaced with placeholders like [EMAIL_1] or [IBAN_1] on the way to the Anthropic API. Detection runs fully in-process. No external redaction service is involved.

⁠Why use it?

• Keep PII and secrets out of model requests by default
• Run locally with no extra SaaS dependency
• Use it as a drop-in proxy for Claude Code
• Inspect detections, logs, and config in a built-in Web UI
• Expose the same detector engine through a REST API

⁠How it works

Claude Code -> privacy-guard-proxy -> Anthropic API
              | masks PII + secrets |

Before a request is forwarded upstream, the proxy scans user messages, tool payloads, and file contents for sensitive data. Matching values are replaced with stable placeholders. Upstream responses are passed through unchanged.

⁠Quick start

⁠Local binary

cp config.example.json config.json
go build -o privacy-guard-proxy .
./privacy-guard-proxy

export ANTHROPIC_BASE_URL=http://127.0.0.1:9880
claude

By default:

• Proxy: http://127.0.0.1:9880
• Web UI + REST API: http://127.0.0.1:9881

⁠Docker Compose

cp config.example.json config.json
docker compose up -d

The compose setup exposes the same two ports and mounts config.json plus ./logs.

⁠What gets masked?

⁠Web UI

If api_port is enabled, the browser UI is available at http://localhost:9881.

First login:

• Username: admin
• Password: admin

You are forced to change the password on first login.

The UI lets you:

• Manage one or more proxy instances
• Choose detectors and whitelists per proxy
• Enable dry_run mode to log findings without modifying requests
• Manage REST API keys without storing plaintext secrets
• Configure default detectors, default whitelist, and CORS
• Inspect live proxy logs
• Test detector behavior interactively

⁠REST API

The built-in API exposes the same detector engine used by the proxy.

# Anonymize text
curl http://localhost:9881/anonymize \
  -H "Content-Type: application/json" \
  -d '{"text":"Meine IBAN: DE89370400440532013000"}' | jq

# Full scan with findings and placeholder mapping
curl http://localhost:9881/scan \
  -H "Content-Type: application/json" \
  -d '{"text":"[email protected], +49 171 1234567"}' | jq

# Use selected detectors for this request only
curl http://localhost:9881/scan \
  -H "Content-Type: application/json" \
  -d '{"text":"...", "detectors":["EMAIL","IBAN","SECRET"]}' | jq

# Health and metrics
curl http://localhost:9881/health
curl http://localhost:9881/metrics

Authentication is optional. If no API keys are configured, requests are accepted without auth.

curl http://localhost:9881/scan \
  -H "X-Api-Key: pgk_..." \
  -H "Content-Type: application/json" \
  -d '{"text":"..."}'

Current limit:

• /scan and /anonymize: 120 requests per minute
• Limit is applied per API key, or per client IP when auth is disabled

⁠Configuration

Start from config.example.json⁠ and adjust as needed:

{
  "api_port": 9881,
  "api_keys": [],
  "default_detectors": [],
  "default_whitelist": [],
  "cors_origins": [],
  "ui_password_hash": "",
  "proxies": [
    {
      "type": "claude-code",
      "port": 9880,
      "upstream": "https://api.anthropic.com",
      "privacy_guard": {
        "url": "",
        "api_key": null,
        "detectors": [],
        "whitelist": [],
        "dry_run": false
      }
    }
  ]
}

For /scan and /anonymize, the runtime whitelist is the combination of default_whitelist and any request-level whitelist.

Legacy configs using a top-level []Config array are still accepted.

⁠Supported detectors

⁠Typical use cases

• Protect prompts and file snippets sent from Claude Code
• Offer a local anonymization API for internal tooling
• Run detector tests against sample text before rolling out changes
• Operate in dry_run mode first to see what would be masked

⁠Development

go build -o privacy-guard-proxy .
go test ./...

Project layout:

internal/
├── api/        # Web UI + REST API
├── detector/   # PII and secret detection engine
└── proxy/      # Reverse proxy and masking pipeline
main.go         # Application entry point
config.json     # Runtime configuration

Frontend assets are vendored under internal/api/static/vendor/, so the Web UI does not depend on external CDNs at runtime.