Blankey

For anyone who wants to use AI without sharing personal details

Let AI fill in your documents. Personal details never leave your computer.

Blankey keeps names, ID numbers, addresses and bank details in an encrypted vault on your computer. Your AI assistant prepares the document and asks Blankey to fill it. You check every value and approve. The AI never sees them.

Download See how it works

Free and open source (MIT). macOS, Windows and Linux.

How it works

Your AI assistant does the paperwork. You keep the details.

  1. Connect your AI assistant

    In Claude Desktop it takes three clicks from the Blankey icon in your menu bar. Developers can add Blankey to Claude Code or Codex with one command. Either way the connection stays on your computer.

  2. Hand it a document

    Give your AI assistant a contract, a form or a letter you already use. It works out where the blanks are, marks them, and tries the result with made-up names and numbers.

  3. Approve the fill

    Your AI assistant asks Blankey to fill in the blanks. You see every one with its value and approve. Blankey makes the finished file on your computer, and the AI only gets a receipt number.

The boundary

What the AI gets, and what it never gets

Your AI assistant works with the shape of your documents, never with the people in them.

Your AI assistant Nothing personal crosses this line Your computer Blankey vault Approve Contract Name Jane Doe ID number 850101 4417 Address 12 Elm Street fill in: name, id, address Filled: document 48
  1. 1Your AI assistant finds the blanks and marks them.
  2. 2It asks Blankey to fill them. It sends the labels, never the answers.
  3. 3Your details come from the encrypted vault. You approve each one.
  4. 4The AI gets a receipt. The finished document stays with you.

What your AI assistant sees

  • The labels"Full name", "ID number", "Home address"
  • How long an answer is14 letters, but not which 14
  • Which saved detail goes in which blank"The client's home address", by name only
  • Whether an answer fitsToo long for the box, without the text itself
  • Previews with made-up namesSo it can check the layout before you fill it
  • A receipt numberfill_set 12, document 48

What stays on your computer

  • The details themselvesNames, ID numbers, addresses, bank account numbers, dates of birth
  • The finished documentsMade and stored encrypted on your computer, shared only when you export them
  • Your password and keysThe master password and the recovery key
  • Your saved choicesWhich detail went in which blank, encrypted with the rest

Inside Blankey

You see everything. Your AI assistant sees the outline.

Blankey fill dialog: every blank with its source and value, waiting for approval
The fill dialog: every blank, its source and its value. Blankey generates nothing until you approve.
More screenshots 6
Templates your AI assistant built from your documents
Templates your AI assistant built from your documents
Profiles in the encrypted vault
Profiles in the encrypted vault
Fill sets: saved choices you can regenerate
Fill sets: saved choices you can regenerate
Generated documents, stored encrypted
Generated documents, stored encrypted
Activity: every request your AI assistant made
Activity: every request your AI assistant made
Your AI assistant asks for missing data; you type it in
Your AI assistant asks for missing data; you type it in

Works with any document

Bring the paperwork you already have

PDF

PDF forms

Forms with fillable boxes, like the ones registries and tax offices publish. Your AI assistant matches every box to a saved detail. The text goes in a bundled font that covers Latin, Cyrillic and Greek, and the result is flattened so it prints the same everywhere.

PDF

Scanned or flat PDFs

No fillable boxes? Your AI assistant reads the printed layout, places the blanks next to the printed labels and checks its work on a preview.

DOCX

Word documents

Any .docx you already use becomes a reusable template. The parts that change, such as names, numbers, amounts and dates, become blanks you can fill again for the next client. The formatting stays as it was.

TYP

Documents that do not exist yet

Describe what you need and your AI assistant writes the document from scratch, using the Typst typesetting system, then fills it with your approved details.

Download Blankey

Free and open source under the MIT License. Works without an internet connection.

Download

Version 0.2.4 · All releases on GitHub · Source

First launch on macOS

Blankey is ad-hoc signed, not notarized, so macOS asks once.

  1. Open the DMG and drag Blankey to Applications.
  2. Open Blankey. macOS says it cannot verify the developer.
  3. Open System Settings > Privacy & Security and click Open Anyway.
  4. Blankey appears in the menu bar. Create your vault: master password plus a recovery key.

Or clear the quarantine flag in Terminal:

xattr -dr com.apple.quarantine /Applications/Blankey.app

Windows and Linux

On Windows, SmartScreen may warn about an unknown publisher: click More info, then Run anyway. On Debian 13 (trixie), install the package with apt; Ubuntu 26.04 users should pick the resolute .deb from the release page instead:

sudo apt install ./Blankey_0.2.4_amd64_trixie.deb

FAQ

Questions

Does the AI ever see my clients' details?

No. Nothing the AI can ask Blankey for returns a value from the vault, and the finished documents are made inside Blankey after you approve. A test pushes marker values through every request the AI can make and checks they never come back. The only values the AI knows are the non-personal ones it suggested itself, like an amount or a date.

What does the AI see, then?

The outline: the labels of the blanks, how long each answer is, which saved detail goes where, whether an answer fits its box, and the receipt numbers for fills and documents. That is enough to prepare and check a document but not enough to read any of your data.

Do I need to be technical?

No. Install Blankey, create your vault with a password, and connect Claude Desktop from the menu bar in three clicks. The commands on this page are for developers who use Claude Code or Codex.

Is it free?

The app is free and open source under the MIT License. Blankey Online, the optional service for web agents such as claude.ai, is a subscription with a free trial.

Which AI assistants work with it?

Claude Desktop, Claude Code and Codex have one-step setup. Any assistant that speaks MCP over streamable HTTP can connect to http://127.0.0.1:8765/mcp. Web agents such as claude.ai connect through Blankey Online.

Does it work offline?

Yes. Blankey has no update checks, sends only anonymous usage counts that you can turn off, and AI assistants on your computer only talk to it over 127.0.0.1. It goes online only if you sign in to Blankey Online, the optional service that lets web agents such as claude.ai reach the app. Your data stays on your computer either way.

Windows or Linux?

Both. Download the .msi for Windows, or the .deb for Debian 13 (trixie) or Ubuntu 26.04 (resolute). On Linux the tray needs StatusNotifier support (on GNOME, install the AppIndicator extension). The Mac build is Apple Silicon only.

Connect your AI assistant

Three clicks, or one command

Blankey must be running. Every option here is also in the menu bar under Connect MCP.

Claude Desktop

Menu barConnect MCPConfigure Claude Desktop

Then restart Claude Desktop. Blankey adds a local bridge to its config and starts the app when needed.

claude.ai and other web agents

Menu barOnlineSign in to Blankey Online

Web agents cannot reach your computer directly, so Blankey keeps an outbound connection to Blankey Online, which passes their requests to the app. Add the connector URL from the Connections page as a custom connector in claude.ai, then allow the agent when Blankey asks. Blankey Online sees the same outline your AI assistant sees and none of the values.

Claude Code

claude mcp add --transport http blankey http://127.0.0.1:8765/mcp

Codex

codex mcp add blankey --url http://127.0.0.1:8765/mcp

Other MCP clients

http://127.0.0.1:8765/mcp

Streamable HTTP, local connections only.

Security model

How the boundary holds

The short version: your details are encrypted on your computer, your AI assistant only ever gets labels and lengths, and a test proves no request hands back a value.

For the technical reader
  • Encrypted per field. Profile values are encrypted with AES-256-GCM. A random data key is wrapped by your master password (Argon2id), optionally by the macOS keychain or Touch ID, and by a one-time recovery key.
  • Metadata is plaintext. Field keys, labels, types and value lengths are not encrypted. That is all the MCP server can read.
  • Real documents render in the app. MCP tools only render templates with example data. Real documents are generated after you approve, stored encrypted, and only their metadata goes back to your AI assistant.
  • You are in the loop. Fill and data requests open a dialog in Blankey. Your AI assistant waits until you save, approve or cancel.
  • Sealed requests. Request payloads and results are sealed to a request key pair (X25519 + AES-GCM): stored while the vault is locked, readable only after unlocking.
  • Local only. The MCP server listens on 127.0.0.1:8765 without authentication, rejects foreign Host and Origin headers (DNS rebinding), and no tool returns personal data.
  • Covered by a test. A test pushes sentinel values through every MCP tool and asserts they never come back.
  • Your call on literals. Your AI assistant may propose non-personal values such as amounts or dates. It sees those because it wrote them; you approve or replace each one.