blckit sits between your keyboard and the AI. It seals API keys, passwords, PHI, and credentials before they leave your browser. You keep typing normally.
Free. No account. Takes 30 seconds to install.
✓ You're on the list. Install it now:
Download the zip, unzip it, then load it in your browser below.
Live demo — try it
Try pasting something sensitive, or pick an example:
How it works
Add blckit to Chrome, Firefox, or Edge. It runs silently in every tab — no setup, no accounts, no configuration required.
Write prompts, messages, and notes in ChatGPT, Claude, Gemini, Copilot, Perplexity, Slack, Gmail, Teams, WhatsApp, Doximity, Zoom, TigerConnect, and Notion exactly as you do today. blckit watches the compose field passively.
When you hit send, blckit intercepts in under 50ms. Detected secrets are replaced with sealed tokens like 〈API_KEY_1〉. The real value never reaches the server.
A tamper-evident Ed25519-signed ledger on your device records every seal. No data leaves your machine. You own the audit trail.
What blckit catches
How we built it
Detection runs locally in the extension. Nothing is sent to our servers — because we don't have any in your data path.
The entire extension is readable on GitHub. Inspect what it does before you install it. Security tools that hide their code are the threat.
Tokens are encrypted with a key that never leaves your device. Your browser is the only place that can unseal them.
Every seal is recorded in an Ed25519-signed, hash-chained local ledger. Tamper-evident proof that protection happened.
Detection runs before your send completes. Under 50ms round-trip. You won't notice it.
After auto-seal, a 10-second toast lets you undo if blckit caught something that wasn't actually sensitive.
Going further