# Shadow > Shadow is an open-source privacy layer for AI: it swaps names, emails, customer data and secrets for realistic, reversible fakes before prompts reach the APIs behind ChatGPT, Claude and other LLMs, then restores them in the answer. Shadow is a single Rust binary (macOS, Linux, Windows) licensed under Apache-2.0. It runs on the endpoint as an HTTPS proxy for every tool, as a gateway base URL for SDKs, or in-process as the `shadow-core` Rust library. It detects personal data, customer names, credentials and machine identifiers in outbound AI requests (OpenAI, Anthropic, Google Gemini, Azure OpenAI, OpenRouter, Mistral, Groq and more), replaces them with format-preserving fakes drawn from a persistent persona (fake emails stay emails, fake card numbers still pass Luhn, fake IBANs still pass mod-97), keeps the mapping in an encrypted local vault, and restores the real values in responses, including streamed responses and tool-call arguments. Unlike DLP that blocks, it keeps AI tools useful. There is no cloud service, account or telemetry. - Docs home: https://getshadow.dev/ - Source code: https://github.com/Tiny-Bubble-Company/shadow - Full documentation as one Markdown file: https://getshadow.dev/llms-full.txt ## Getting started - [Get started with Shadow, the open-source privacy layer for AI](https://getshadow.dev/getting-started/): Install Shadow and mask PII and secrets in OpenAI (ChatGPT models), Anthropic (Claude) and other LLM API traffic in five minutes. Introduction, quick start and installation for macOS, Linux, Windows and Docker. - [Introduction](https://getshadow.dev/getting-started/introduction/): What 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 start](https://getshadow.dev/getting-started/quick-start/): Install Shadow, create a persona, start the local proxy and send your first PII-masked request to OpenAI or Anthropic in about five minutes. - [Installation](https://getshadow.dev/getting-started/installation/): Install the Shadow binary on macOS, Linux or Windows: one-line install script, Cargo from source, Docker, or a background service that starts at login. ## Integrate - [Integrate Shadow: proxy, gateway, Docker, Kubernetes or Rust](https://getshadow.dev/integrate/): Ways to put Shadow in front of AI traffic: a local HTTPS proxy for desktop tools, a gateway base URL for SDKs, a Docker or Kubernetes sidecar, any HTTP endpoint, or the Rust library. - [Integration modes](https://getshadow.dev/integrate/overview/): Choose how to run Shadow: HTTPS proxy for AI tools on a machine, gateway base URL for SDKs, or the embedded Rust library. How each mode works and when to use it. - [Proxy mode](https://getshadow.dev/integrate/proxy-mode/): Run Shadow as an HTTPS forward proxy that masks PII in the AI API traffic of every tool on a machine: trusting the local CA, intercepted hosts, bypass rules and PAC files. - [Gateway mode](https://getshadow.dev/integrate/gateway-mode/): Mask PII in OpenAI, Anthropic, OpenRouter and Gemini calls by pointing your SDK's base URL at Shadow. Examples in Python, Node.js and curl. No CA needed. - [Embed in Rust](https://getshadow.dev/integrate/rust/): Embed the shadow-core Rust crate to mask and restore LLM calls in-process: sessions, intent policy, JSON and streaming helpers, no proxy hop. - [Docker and Kubernetes](https://getshadow.dev/integrate/docker-kubernetes/): Run Shadow as a sidecar container in Docker or Kubernetes to mask PII in your service's LLM calls, with persistent state and controlled egress. - [Integrating any endpoint](https://getshadow.dev/integrate/any-endpoint/): Put Shadow in front of anything that calls an LLM: Claude Code and coding assistants, IDEs, agents, desktop apps, custom APIs and self-hosted gateways. ## Concepts - [How Shadow works: detection, vault, personas and policy](https://getshadow.dev/concepts/): Concepts behind Shadow's PII masking for LLMs: how sensitive values are detected, stored in the encrypted vault, replaced with persona-consistent fakes, and restored in streams, tool calls and files. - [How it works](https://getshadow.dev/concepts/how-it-works/): How Shadow masks AI traffic end to end: interception, detection, intent policy, reversible translation and restoration of streamed responses. - [Personas](https://getshadow.dev/concepts/personas/): Personas give Shadow one coherent fake identity per machine (company, people, domain, hostnames) so masked prompts stay realistic and consistent. - [The vault](https://getshadow.dev/concepts/vault/): How Shadow's local vault stores the real-to-fake mapping: ChaCha20-Poly1305 encryption at rest, multi-process sharing, export and forgetting values. - [Detection](https://getshadow.dev/concepts/detection/): How Shadow detects PII and secrets: checksummed patterns, secrets, dictionary terms, local machine facts, an optional NER model and Microsoft Presidio. - [Intent-aware policy](https://getshadow.dev/concepts/intent-policy/): Shadow classifies each AI request as act, report, code or converse and picks a fake, token, real value or redaction for every sensitive value. - [File masking](https://getshadow.dev/concepts/file-masking/): How Shadow masks PII in files sent to LLMs: multipart uploads, base64 and data URIs in text, CSV, JSON, DOCX, XLSX, PPTX and PDF formats. - [Tool calls and agents](https://getshadow.dev/concepts/tool-calls/): How Shadow keeps AI agents working on masked data: tool-call arguments are restored locally before tools run, and provider-hosted tools follow policy. - [Activity dashboard](https://getshadow.dev/concepts/activity-dashboard/): See what Shadow is doing on your machine. A web dashboard, a terminal view and a menu-bar app show the AI traffic Shadow checked, the sensitive data it masked, and the requests it blocked, by data type, destination and app. ## Benchmarks - [PII redaction benchmark: Shadow vs Presidio, GLiNER, OpenAI Privacy Filter, LLM Guard](https://getshadow.dev/benchmarks/): Reproducible PII masking benchmark for LLM prompts. Leak rate, over-masking, precision, recall, round trip and latency for Shadow, Microsoft Presidio, GLiNER, OpenAI Privacy Filter, LLM Guard and scrubadub. ## Compare - [Shadow vs alternatives: the AI data-leak prevention landscape](https://getshadow.dev/compare/): Compare Shadow with Presidio, LLM Guard, LiteLLM, Nightfall, Netskope, Skyflow and 25 more tools that stop sensitive data leaking into LLM prompts. - [Best open-source PII redaction tools for LLMs in 2026](https://getshadow.dev/compare/open-source-pii-redaction-tools/): An honest guide to open-source PII redaction tools for LLM prompts in 2026, including Presidio, LLM Guard, GLiNER, OpenAI Privacy Filter, Rehydra and Shadow. - [AI DLP tools compared: block vs redact vs pseudonymise](https://getshadow.dev/compare/ai-dlp-tools/): AI DLP tools compared by what they do to sensitive data: block, redact or pseudonymise. Netskope, Zscaler, Purview, Nightfall, Harmonic and Shadow. - [LLM gateways with PII masking compared (2026)](https://getshadow.dev/compare/llm-gateways-with-pii-masking/): Which LLM and AI gateways mask PII, and which restore it? LiteLLM, Portkey, Kong, Cloudflare, Bedrock Guardrails and Shadow compared. - [Privacy vaults for LLMs: Skyflow, Protecto, Private AI and alternatives](https://getshadow.dev/compare/privacy-vaults-for-llms/): Privacy vaults for LLMs compared: Skyflow, Protecto, Private AI, Tonic Textual, Wald.ai and Shadow's local encrypted vault. Tokens, fakes and re-identification. - [Shadow vs AWS Comprehend and Bedrock Guardrails — a self-hosted alternative](https://getshadow.dev/compare/aws-comprehend-bedrock-guardrails/): Shadow vs AWS Comprehend PII and Amazon Bedrock Guardrails. AWS detects, blocks or tags PII; Shadow masks with reversible fakes and restores answers. - [Shadow vs Azure AI Language PII — open-source Azure PII alternative for LLMs](https://getshadow.dev/compare/azure-ai-language-pii/): Shadow vs Azure AI Language PII detection. Azure masks or synthesises PII one way; Shadow uses reversible fakes and restores LLM responses locally. - [Shadow vs Cloudflare AI Gateway DLP — alternative that masks instead of blocking](https://getshadow.dev/compare/cloudflare-ai-gateway/): Shadow vs Cloudflare AI Gateway DLP. Cloudflare flags or blocks prompts with sensitive data; Shadow masks with reversible fakes and restores answers. - [Shadow vs DataFog — open-source DataFog alternative for LLM privacy](https://getshadow.dev/compare/datafog/): Shadow vs DataFog for LLM PII protection. DataFog redacts, replaces or hashes PII; Shadow uses reversible fakes and restores streamed responses. - [Shadow vs GLiNER PII — zero-shot PII models inside an LLM privacy proxy](https://getshadow.dev/compare/gliner-pii/): Shadow vs GLiNER PII models (urchade, NVIDIA, Knowledgator). GLiNER detects PII spans; Shadow runs it as a detector and adds reversible masking. - [Shadow vs Google Sensitive Data Protection — Cloud DLP alternative for LLMs](https://getshadow.dev/compare/google-sensitive-data-protection/): Shadow vs Google Cloud Sensitive Data Protection (Cloud DLP). Google offers reversible FPE; Shadow adds realistic fakes, a local proxy and streaming restore. - [Shadow vs Harmonic Security — open-source Harmonic alternative for AI data protection](https://getshadow.dev/compare/harmonic-security/): Shadow vs Harmonic Security. Harmonic's browser extension warns, blocks or redirects AI use; Shadow masks API prompts with reversible fakes. - [Shadow vs Kong AI Gateway — open-source alternative to Kong ai-sanitizer](https://getshadow.dev/compare/kong-ai-gateway/): Shadow vs Kong AI Gateway's ai-sanitizer plugin. Both can use synthetic values and restore; Shadow is open source, local and streams restores. - [Shadow vs Lakera Guard — Lakera alternative for PII masking in LLM prompts](https://getshadow.dev/compare/lakera/): Shadow vs Lakera Guard (Check Point AI Guardrails). Lakera detects PII and prompt attacks; Shadow masks PII with reversible fakes and restores answers. - [Shadow vs LangChain PIIMiddleware — reversible PII masking for agents](https://getshadow.dev/compare/langchain-pii-middleware/): Shadow vs LangChain PIIMiddleware for agent PII protection. LangChain redacts, masks or hashes one way; Shadow restores values in tool calls and streams. - [Shadow vs Lasso Security — open-source Lasso alternative for GenAI data protection](https://getshadow.dev/compare/lasso-security/): Shadow vs Lasso Security. Lasso masks or alerts with plain-English contextual policies; Shadow masks with reversible fakes and restores answers. - [Shadow vs LiteLLM — LiteLLM PII masking alternative with streaming restore](https://getshadow.dev/compare/litellm/): Shadow vs LiteLLM proxy for PII masking. LiteLLM routes models and runs guardrails; Shadow adds reversible fakes and streaming, tool-call restore. - [Shadow vs LLM Guard — open-source LLM Guard alternative for PII masking](https://getshadow.dev/compare/llm-guard/): Shadow vs LLM Guard (Protect AI). Both reverse PII in LLM responses; Shadow adds realistic fakes, streaming restore, tool calls and a proxy. - [Shadow vs Microsoft Purview — open-source Purview DSPM for AI alternative](https://getshadow.dev/compare/microsoft-purview/): Shadow vs Microsoft Purview DSPM for AI. Purview warns, blocks and audits Copilot and AI sites; Shadow masks API prompts and restores responses. - [Shadow vs NeMo Guardrails — NeMo Guardrails alternative for PII masking](https://getshadow.dev/compare/nemo-guardrails/): Shadow vs NVIDIA NeMo Guardrails for PII. NeMo masks or blocks with labels; Shadow uses reversible fakes and restores responses and tool calls. - [Shadow vs Netskope — open-source Netskope GenAI DLP alternative for AI traffic](https://getshadow.dev/compare/netskope/): Shadow vs Netskope One GenAI DLP. Netskope blocks, coaches and redacts inline; Shadow restores fakes in streams, tool calls and files. - [Shadow vs Nightfall — open-source Nightfall AI alternative for LLM prompts](https://getshadow.dev/compare/nightfall/): Shadow vs Nightfall AI DLP. Nightfall blocks or redacts prompts in the browser and on endpoints; Shadow masks with reversible fakes and restores answers. - [Shadow vs OpenAI Privacy Filter — using the open-weight PII model in a proxy](https://getshadow.dev/compare/openai-privacy-filter/): Shadow vs OpenAI Privacy Filter. Privacy Filter is a free PII detection model; Shadow can run it as a detector and adds reversible masking and restore. - [Shadow vs Palo Alto AI Access Security — open-source alternative for AI APIs](https://getshadow.dev/compare/palo-alto-ai-access/): Shadow vs Palo Alto Networks AI Access Security and Prisma Browser. Palo Alto blocks or allows AI apps; Shadow masks prompts with reversible fakes. - [Shadow vs Portkey — Portkey PII redaction alternative that restores responses](https://getshadow.dev/compare/portkey/): Shadow vs Portkey AI gateway for PII. Portkey redacts one way via partner guardrails; Shadow uses reversible fakes and restores streams and tool calls. - [Shadow vs Presidio — open-source Presidio alternative for LLM traffic](https://getshadow.dev/compare/presidio/): Shadow vs Microsoft Presidio for LLM prompts. Presidio detects and redacts PII; Shadow adds reversible fakes, streaming restore and a proxy. - [Shadow vs Private AI — open-source Private AI alternative for LLM prompts](https://getshadow.dev/compare/private-ai/): Shadow vs Private AI for masking PII in LLM prompts. Compare multilingual detection, re-identification, streaming, deployment and price. - [Shadow vs Prompt Security — open-source Prompt Security alternative for LLM data](https://getshadow.dev/compare/prompt-security/): Shadow vs Prompt Security (SentinelOne). Prompt Security filters or blocks AI prompts; Shadow masks them with reversible fakes and restores answers. - [Shadow vs Protecto — open-source Protecto alternative for LLM data privacy](https://getshadow.dev/compare/protecto/): Shadow vs Protecto (GPTGuard) for masking PII in AI prompts. Compare semantic tokens vs realistic fakes, unmasking, streaming and deployment. - [Shadow vs Rehydra — open-source local PII proxies for LLMs compared](https://getshadow.dev/compare/rehydra/): Shadow vs Rehydra, two open-source local proxies that mask PII before LLM calls and restore it. Compare fakes vs placeholders, streaming and files. - [Shadow vs Skyflow — open-source Skyflow LLM Privacy Vault alternative](https://getshadow.dev/compare/skyflow/): Shadow vs Skyflow LLM Privacy Vault. Compare vault tokens vs realistic fakes, re-identification, files, streaming, deployment and pricing. - [Shadow vs Strac — open-source Strac alternative for AI data protection](https://getshadow.dev/compare/strac/): Shadow vs Strac DLP for ChatGPT and AI apps. Compare browser-extension DLP with an open-source proxy that masks prompts with reversible fakes. - [Shadow vs Tonic Textual — open-source Tonic Textual alternative for live LLM traffic](https://getshadow.dev/compare/tonic-textual/): Shadow vs Tonic Textual. Tonic redacts and synthesises data for datasets; Shadow masks live AI traffic with reversible fakes. Compare features and pricing. - [Shadow vs Wald.ai — open-source, self-hosted Wald.ai alternative](https://getshadow.dev/compare/wald-ai/): Shadow vs Wald.ai for safe use of ChatGPT and Claude. Compare contextual substitution, restoration, deployment and pricing with a free local proxy. - [Shadow vs Zscaler — open-source Zscaler GenAI DLP alternative for AI APIs](https://getshadow.dev/compare/zscaler/): Shadow vs Zscaler GenAI protection. Zscaler blocks, isolates and logs AI app use; Shadow masks API prompts with reversible fakes and restores them. ## Use cases - [AI privacy use cases: mask PII and secrets in LLM prompts with Shadow](https://getshadow.dev/use-cases/): Step-by-step guides: stop PII leaks to ChatGPT, redact prompts for OpenAI and Claude, protect secrets from coding assistants, agents, RAG and documents. - [How to stop employees pasting customer data into ChatGPT](https://getshadow.dev/use-cases/stop-pii-leaks-to-chatgpt/): Stop customer names, emails and IDs leaking into ChatGPT and other LLMs without banning AI: give staff an approved client that masks data through Shadow. - [How to redact PII before sending prompts to the OpenAI API](https://getshadow.dev/use-cases/redact-pii-before-sending-to-openai-api/): Mask names, emails, cards and secrets in OpenAI API requests with one base URL change, and get real values back in responses, streams and tool calls. - [How to anonymise prompts before sending them to Claude](https://getshadow.dev/use-cases/anonymize-prompts-for-claude/): Mask personal data, customer names and secrets in Anthropic Claude API requests locally, and restore them in streamed answers and tool use. - [How to keep API keys and internal hosts out of AI coding assistants](https://getshadow.dev/use-cases/protect-secrets-from-ai-coding-assistants/): Stop Claude Code, Aider, Cline and other AI coding tools sending API keys, internal hostnames, IPs and usernames to the model. Set up Shadow in minutes. - [How to use ChatGPT, Claude and other LLMs in line with GDPR](https://getshadow.dev/use-cases/gdpr-compliant-llm-usage/): Use LLMs with less personal data: Shadow pseudonymises prompts locally (GDPR Art. 4(5), 25, 32) before they reach OpenAI, Anthropic or Gemini. - [How to use LLMs with patient data more safely under HIPAA](https://getshadow.dev/use-cases/hipaa-safe-llm-usage/): Keep PHI out of OpenAI, Azure OpenAI and Claude prompts: Shadow masks patient identifiers locally, supports minimum necessary, and restores answers. - [How to mask PII in LLM agents without breaking tool calls](https://getshadow.dev/use-cases/mask-pii-in-llm-agents-and-tool-calls/): Keep personal data away from the model while agents still email, query and update the real records: recipients pass through, everything else is restored locally. - [Reversible pseudonymisation for LLMs: mask data and restore it in the answer](https://getshadow.dev/use-cases/reversible-pseudonymization-for-llms/): How to pseudonymise prompts for OpenAI, Anthropic or Gemini with realistic, reversible fakes, keep the key local, and get real values back in responses. - [How to redact PDFs, Word and Excel files before uploading them to AI](https://getshadow.dev/use-cases/redact-documents-before-uploading-to-ai/): Mask names, emails and IDs in DOCX, XLSX, PPTX, CSV and PDF uploads to OpenAI, Anthropic or Gemini automatically, with Office files kept valid. - [Self-hosted AI gateway with PII masking: put Shadow in front of any LLM API](https://getshadow.dev/use-cases/self-hosted-ai-gateway-with-pii-masking/): Run a self-hosted, open-source gateway that masks PII and secrets before requests reach OpenAI, Anthropic, Azure OpenAI, Bedrock or vLLM, and restores answers. - [How to protect customer data in RAG pipelines sent to LLMs](https://getshadow.dev/use-cases/protect-customer-data-in-rag-pipelines/): Keep customer names, emails and IDs in retrieved chunks away from OpenAI or Anthropic. Mask RAG context at generation time with Shadow and restore the answer. - [LLM data loss prevention: DLP for ChatGPT, Claude and AI APIs without blocking](https://getshadow.dev/use-cases/llm-data-loss-prevention-dlp/): Open-source DLP for LLM traffic: Shadow masks PII, customer data and secrets in AI API requests with reversible fakes instead of blocking them. - [Shadow AI governance: how to manage unsanctioned AI tools without banning AI](https://getshadow.dev/use-cases/shadow-ai-governance/): Shadow AI is employees using unapproved AI tools. Learn how to govern it, and how the open-source Shadow privacy layer makes a sanctioned path safe to use. - [Privacy for AI in customer support: mask customer data in tickets and agents](https://getshadow.dev/use-cases/privacy-for-ai-in-customer-support/): Use LLMs for ticket replies, summaries and support agents without sending customer names, emails, orders or card numbers to the provider. Restored in answers. ## Industries - [Secure ChatGPT and LLM use by industry: protect regulated data with Shadow](https://getshadow.dev/industries/): How healthcare, finance, legal, public sector and 14 more industries use ChatGPT, Claude and LLM APIs without sending personal or confidential data. - [Secure ChatGPT and LLM use in healthcare: protect PHI with Shadow](https://getshadow.dev/industries/healthcare/): Keep patient names, contact details and identifiers out of OpenAI, Anthropic and Gemini prompts. Shadow masks PHI locally and restores it in the answer. - [Secure LLM use in banking and financial services: mask customer and card data with Shadow](https://getshadow.dev/industries/financial-services/): Keep IBANs, card numbers, customer names and account data out of AI prompts. Shadow masks them locally with checksum-valid fakes and restores the answer. - [Secure generative AI in insurance: protect policyholder and claims data with Shadow](https://getshadow.dev/industries/insurance/): Use LLMs on claims notes, adjuster reports and policyholder letters without sending personal data to the provider. Shadow masks it locally and restores it. - [Secure ChatGPT and LLM use for law firms: protect client confidentiality with Shadow](https://getshadow.dev/industries/legal/): Keep client names, matter codenames and counterparties out of AI prompts and uploaded contracts. Shadow masks them locally and restores the answer. - [Secure generative AI in government and the public sector: mask citizen data with Shadow](https://getshadow.dev/industries/government-public-sector/): Self-hosted, no-telemetry masking of citizen and case data before it reaches an AI provider. Runs inside your boundary; restores answers locally. - [Secure ChatGPT and AI use in education: protect student data under FERPA with Shadow](https://getshadow.dev/industries/education/): Let staff and edtech apps use LLMs without sending student names, IDs and records to the provider. Shadow masks them locally and restores the answer. - [Secure generative AI in pharma and life sciences: protect clinical and R&D data with Shadow](https://getshadow.dev/industries/pharma-life-sciences/): Mask investigator, patient and partner names, compound codenames and internal systems before AI requests leave. Self-hosted, reversible, no telemetry. - [Secure LLM use for SaaS and technology companies: keep customer data out of AI prompts](https://getshadow.dev/industries/saas-technology/): Mask customer emails, IPs, hostnames and API keys in support, engineering and product AI traffic. Self-hosted proxy, gateway or sidecar; answers restored. - [Secure AI for e-commerce and retail: protect customer and payment data with Shadow](https://getshadow.dev/industries/ecommerce-retail/): Use LLMs for customer service, order operations and analytics without sending shopper names, addresses or card numbers to the AI provider. - [Secure LLM use in telecommunications: keep subscriber data and network details out of AI prompts](https://getshadow.dev/industries/telecommunications/): Mask subscriber names, phone numbers, IPs, MACs and internal hostnames before telecom teams send prompts to OpenAI, Anthropic or Gemini. Self-hosted. - [Secure LLM use in manufacturing: protect trade secrets and supplier data in AI prompts](https://getshadow.dev/industries/manufacturing/): Mask programme codenames, part names, supplier and customer names before engineers send prompts to OpenAI, Anthropic or Gemini. Self-hosted, open source. - [Secure LLM use in energy and utilities: keep OT details and customer data out of AI prompts](https://getshadow.dev/industries/energy-utilities/): Mask OT hostnames, IPs, credentials and customer billing data before utility teams use OpenAI, Anthropic or Gemini. Self-hosted, no telemetry, open source. - [Secure LLM use in media and entertainment: keep unreleased titles and talent names out of AI prompts](https://getshadow.dev/industries/media-entertainment/): Mask unreleased titles, codenames, talent and deal terms before writers, producers and marketers use OpenAI, Anthropic or Gemini. Scripts masked in place. - [Secure LLM use in HR and recruiting: protect candidate and employee data in AI prompts](https://getshadow.dev/industries/hr-recruiting/): Mask candidate and employee names, contact details and IDs in CVs and HR documents before they reach OpenAI, Anthropic or Gemini. Self-hosted, reversible. - [Secure LLM use in consulting and professional services: keep client data out of AI prompts](https://getshadow.dev/industries/consulting-professional-services/): Mask client names, engagement codenames and contacts in prompts, decks and spreadsheets before consultants use OpenAI, Anthropic or Gemini. Self-hosted. - [Secure LLM use in automotive: protect connected-car, driver and supplier data in AI prompts](https://getshadow.dev/industries/automotive/): Mask driver names, contact details, internal hosts, secrets and programme codenames before automotive teams use OpenAI, Anthropic or Gemini. Self-hosted. - [Secure ChatGPT and LLM use for nonprofits: protect donor and beneficiary data for free](https://getshadow.dev/industries/nonprofit/): Free, open-source way for charities and NGOs to mask donor, volunteer and beneficiary data before staff use OpenAI, Anthropic or Gemini. No account needed. - [Secure ChatGPT and LLM use in real estate: protect tenant and buyer data in AI prompts](https://getshadow.dev/industries/real-estate/): Mask tenant, buyer and landlord names, contact details, bank data and IDs in leases and listings before agents use OpenAI, Anthropic or Gemini. ## Company size - [Rolling out AI privacy by company size: Shadow from one laptop to a fleet](https://getshadow.dev/company-size/): How solo developers, startups, small businesses, mid-market firms and enterprises deploy Shadow to keep customer data and secrets out of AI tools. - [AI privacy for solo developers and freelancers: keep client data and keys out of LLMs](https://getshadow.dev/company-size/solo-developers-freelancers/): Use Claude Code, Aider and LLM APIs on client work without sending client names, customer data or API keys. Free, local, five-minute setup. - [LLM data privacy for startups: protect customer data in AI tools and features](https://getshadow.dev/company-size/startups/): Keep customer PII and secrets out of OpenAI and Anthropic from day one: engineer laptops, product AI features and security questionnaires. Free and self-hosted. - [AI data privacy for small businesses: use ChatGPT-style tools without leaking customer data](https://getshadow.dev/company-size/small-business/): A practical guide for SMBs: keep customer names, emails and payment details out of AI tools with free, self-hosted Shadow. Setup, limits and checklist. - [AI data protection for mid-market companies: roll out PII masking with your MDM](https://getshadow.dev/company-size/mid-market/): Deploy Shadow across hundreds of laptops and internal AI apps: MDM scripts, managed configuration, pilot groups, sidecars and an honest list of gaps. - [Enterprise LLM data protection: where Shadow fits next to DLP, SSE and AI gateways](https://getshadow.dev/company-size/enterprise/): How enterprises use Shadow to mask PII and secrets in AI API traffic at scale: endpoints, sidecars, existing DLP and gateways, and the gaps to plan for. - [Generative AI controls for regulated enterprises: evidence-ready PII masking with Shadow](https://getshadow.dev/company-size/regulated-enterprise/): For banks, insurers, health systems and public bodies: deploying Shadow as a documented AI data control, with risk assessment, testing and change control. ## Reference - [Shadow reference: CLI, configuration, providers and security](https://getshadow.dev/reference/): Reference documentation for Shadow: every CLI command, every configuration option, supported AI providers, the security model, troubleshooting and FAQ. - [Configuration](https://getshadow.dev/reference/configuration/): Reference for every shadow.toml setting: persona, detectors, NER model, Presidio, policy, files, proxy and gateway routes, with defaults and examples. - [CLI](https://getshadow.dev/reference/cli/): Reference for the shadow command line: init, run, install, status, mask, unmask, scan, vault, terms, hosts, top, activity and dashboard, with every subcommand and flag. - [Supported providers and hosts](https://getshadow.dev/reference/providers/): AI providers Shadow supports: OpenAI, Anthropic, Gemini, Azure OpenAI, Bedrock, Mistral and more. Intercepted hosts, gateway routes and API formats. - [Security model](https://getshadow.dev/reference/security/): Shadow's security model: what it protects from AI providers, what it trusts, how the vault and local CA are secured, and its known limitations. - [FAQ](https://getshadow.dev/reference/faq/): Answers to common questions about Shadow: latency, streaming, message recipients, agents, files, answer quality, Presidio, DLP, telemetry and licensing. - [Troubleshooting](https://getshadow.dev/reference/troubleshooting/): Fix common Shadow problems: untrusted certificates, connection refused, gateway 404s, values not masked, fakes left in answers, streaming and vault errors. ## Optional - [Shadow project: roadmap, changelog and contributing](https://getshadow.dev/project/): Shadow is free, open-source software under Apache-2.0. See the roadmap and changelog, and learn how to contribute code, detectors, docs and benchmarks. - [Roadmap](https://getshadow.dev/project/roadmap/): What is planned for Shadow, the open-source privacy layer for AI: shipped features and upcoming directions. Directions, not promises. - [Contributing](https://getshadow.dev/project/contributing/): How to contribute to Shadow: build from source, run the tests, work on the docs and detectors, and send a pull request. - [Changelog](https://getshadow.dev/project/changelog/): Release notes for Shadow: notable changes, new features and fixes in each version, following Keep a Changelog and Semantic Versioning.