Privacy Policy for PrivyMermaid

Last Updated: January 2026

Overview

PrivyMermaid ("the Extension") is a local-first Mermaid diagram editor. This Privacy Policy explains how we handle information when you use our Chrome extension.

Our Privacy Commitment

PrivyMermaid does not collect, store, or transmit any personal data to external servers. The extension is designed to keep all your data on your device.

Data Collection

What We DO NOT Collect

• Personal information (name, email, address)
• Usage analytics or telemetry
• Browsing history
• Diagram content or prompts sent to our servers (we have no servers)
• Any data transmitted to external servers

What Is Stored Locally

The following data is stored locally on your device only using Chrome's storage API:

• Diagram list — Your saved diagrams (name, source, timestamps)
• Settings — Ollama endpoint URL, model, temperature, theme
• Prompt templates — Your custom Fix/Refactor prompts
• Active diagram ID — Which diagram is currently open

This data never leaves your device and is only accessible by the extension.

Extension Permissions

• storage — Save diagram list, settings, prompt templates locally. All stays on your device.
• contextMenus — Add right-click menu items. Selected text is passed only to the extension's own page, not to any server.
• Host access (localhost / 127.0.0.1) — Connect to your local Ollama instance for optional "Ask" and "Fix Diagram" / "Refactor" features only.

Network Communications

PrivyMermaid only makes network requests to your local machine (http://localhost or http://127.0.0.1, typically port 11434) for optional Ollama features. All AI processing happens on YOUR machine. No data is sent to the internet. Diagram rendering uses a bundled Mermaid library (offline); no CDN is required.

Third-Party Software

• Mermaid — Local copy (MIT License) for rendering. No data sent to Mermaid or any third party.
• Ollama — Optional; you install and run on your own machine. Extension only talks to your local Ollama instance.

Data Security

All stored data uses Chrome's built-in storage, which is sandboxed to the extension. No telemetry, no analytics, no tracking.

Changes to This Policy

We may update this Privacy Policy from time to time. The "Last Updated" date at the top will be revised when changes are made.

Contact

For privacy-related questions, please use the Chrome Web Store support page for the extension.