Stand-In: Private details stay private in AI chats

Masks names, ID and account numbers when you paste into ChatGPT, Claude or Gemini, then restores them in the answer. On-device.

Use AI on real work without handing it real names. Stand-In catches private details the moment you paste into an AI chat and swaps them for placeholders like [PERSON_1] and [ACCOUNT_1]. The AI still understands who is who and gives you a full answer. When it replies, select the answer, right-click › Restore with Stand-In, and the real names and numbers come back in a side panel the chat site can't read. WHAT IT CATCHES • Names, including first or last names on their own later in the chat • SIN and SSN, business numbers and tax IDs • Bank, card, IBAN and other account numbers • Emails, phone numbers, street addresses, postal and ZIP codes, dates of birth • Optional packs: health and patient IDs, case and court file numbers, employee IDs and pay, dollar amounts • Anything you add to your own "always mask" list WORKS WITH ChatGPT, Claude, Gemini, Microsoft Copilot and Perplexity. PRIVATE BY DESIGN • Everything runs in your browser. No servers, no accounts, no analytics. • The chat site only ever receives the masked text. • Each tab keeps its own key, deleted when you close the tab. • Save a locked key (AES-256, your passphrase) to restore answers later, including in the Stand-In web app. BUILT FOR Accountants and bookkeepers, lawyers and paralegals, clinics and therapists, HR teams, and anyone who wants AI's help with a bill, lease or form without giving away their identity. Detection is a safety net, not a guarantee. Stand-In highlights what it catches so you can check before you send. For PDFs, Word and Excel files, scans and photos of forms, use the Stand-In app at trystandin.com/app.