Get started with Shadow, the open-source privacy layer for AI

Shadow replaces names, emails, customer data and secrets with realistic, reversible fakes before a request reaches an AI provider, and restores them in the answer. Start with the introduction, or go straight to the five-minute quick start.

• IntroductionWhat Shadow is: an open-source privacy layer that masks PII and secrets in prompts to ChatGPT, Claude and other LLMs with reversible fakes, unlike blocking DLP.
• Quick startInstall Shadow, create a persona, start the local proxy and send your first PII-masked request to OpenAI or Anthropic in about five minutes.
• InstallationInstall the Shadow binary on macOS, Linux or Windows: one-line install script, Cargo from source, Docker, or a background service that starts at login.

Frequently asked questions

How long does it take to set up Shadow?

About five minutes: install the binary, run shadow init, start shadow run and point your SDK's base URL at http://127.0.0.1:8877/gw/openai/v1. Gateway mode needs no certificate setup.

Does Shadow send data to the cloud?

No. Shadow has no hosted component, account or telemetry. The only outbound traffic is the masked request you were already sending to your AI provider, and the real-to-fake mapping stays in an encrypted vault on your machine.

Which operating systems does Shadow run on?

macOS, Linux and 64-bit Windows, as a single static binary. The repository also ships a Dockerfile for running it in containers.