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massCodeIO/massCode · source
Snapshot 0 · 2026-11-04T12:47:26Z · TypeScript · AGPL-3.0
Content fingerprint
543e871a8ccc69c7717433979f9500a453b962eb1263d45c0d6506d17d326303GitHub description at capture
A free, open-source developer workspace. Snippets, notes, HTTP requests, calculations, and dev tools in one local-first app.
README at capture
<p align="center">
<img src="./.github/assets/logo.png" alt="massCode" width="150">
</p>
<h1 align="center">massCode</h1>
<p align="center">
A free, open-source developer workspace.
</p>
<p align="center">
<strong>Snippets, notes, HTTP requests, calculations, drawings, and dev tools in one local-first app.</strong>
<br>
Your workspace is stored locally as plain Markdown files.
</p>
<p align="center">
<img alt="GitHub package.json version" src="https://img.shields.io/github/package-json/v/massCodeIO/massCode">
<img alt="GitHub stars" src="https://img.shields.io/github/stars/massCodeIO/massCode?style=flat">
<img alt="GitHub All Releases" src="https://img.shields.io/github/downloads/massCodeIO/massCode/total">
<img alt="GitHub" src="https://img.shields.io/github/license/massCodeIO/massCode">
</p>
<p align="center">
<a href="https://github.com/massCodeIO/massCode/releases">Download</a> |
<a href="https://masscode.io/documentation/">Documentation</a> |
<a href="https://github.com/massCodeIO/massCode/blob/master/CHANGELOG.md">Changelog</a>
</p>
<p align="center">
Extensions:
<a href="https://marketplace.visualstudio.com/items?itemName=AntonReshetov.masscode-assistant">VS Code</a> |
<a href="https://www.raycast.com/antonreshetov/masscode">Raycast</a>
</p>
<br>
<p align="center">
<img src="./docs/website/public/preview.png" alt="massCode screenshot" width="800">
</p>
<p align="center">
<sub>Available for macOS, Windows, and Linux</sub>
</p>
<br>
<br>
## Support
massCode is free and open source. But building and maintaining a quality tool takes time. Your support helps keep development going and new features coming.
<div align="center">
[](https://opencollective.com/masscode)
[](https://paypal.me/antongithub)
[](https://antonreshetov.gumroad.com/l/masscode)
</div>
<p align="center">
<strong>SPONSORS</strong>
</p>
<p align="center">
<a href="https://torsher.app/?ref=github/massCodeIO">
<img src='.github/assets/Torsher.svg' alt='Torsher — self-hosted media center for the TV'>
</a>
<a href="https://mysigmail.com/?ref=github/massCodeIO">
<img src='.github/assets/MySigMail.svg'>
</a>
</p>
## About
Originally a snippet manager, massCode now brings together snippets, notes, HTTP requests, calculations, drawings, and developer tools in one desktop app, so everyday work stays in one place.
## Features
### Code Snippets
Use massCode as a focused snippet workspace with multi-level folders, tags, and fragments for organizing reusable code across projects and languages.
- 160+ syntax grammars out of the box (600+ supported via `.tmLanguage`)
- Integrated [Prettier](https://prettier.io) for code formatting
- Real-time HTML & CSS preview for quick prototyping
- JSON Visualizer for exploring nested structures as interactive graphs
- Export snippets as polished images with customizable themes
### Notes
Write longer markdown documents right next to your snippets: project docs, drafts, research notes, and personal knowledge bases.
- Task notes with status, priority, due dates, and Today / Upcoming / Completed views
- Completed task cleanup and auto-clean scheduling
- Dashboard with activity overview, recent notes, top linked notes, and a notes graph preview
- Editor, Live Preview, and Preview modes
- Editable markdown tables with row and column controls
- Internal links to notes, snippets, and HTTP requests, with placeholders for items you plan to create later
- Note inspector with section navigation and reordering, link filters, and grouped callouts
- Fullscreen notes graph for exploring internal links between notes
- Integrated [Mermaid](https://mermaid-js.github.io/mermaid/#) diagrams
- Mind maps generated from markdown heading structure
- Fullscreen presentation mode for demos and meetings
- Callout blocks, including TODOs for unfinished writing, and image embedding
### HTTP Client
Build and test API workflows alongside your code snippets and project notes.
- Send HTTP and GraphQL requests and exchange WebSocket messages
- Organize collections and nested folders with shared auth, headers, variables, and scripts
- Switch environments, protect tokens with local secret variables, and pass response values between requests
- Check responses with assertions and JavaScript tests, then run collections or folders in sequence
- Edit query parameters, headers, authentication, and JSON, text, form, or file payloads
- Generate request code for 20 languages and runtimes, including cURL
- Inspect responses and saved history, debug traffic in Console, and manage cookies and transport settings
- Import collections from OpenAPI, Postman, and Bruno
See the [HTTP documentation](https://masscode.io/documentation/http/) to get started.
### Math Notebook
A calculator-style notebook for natural-language calculations, conversions, and date math without leaving your workflow.
- Arithmetic, percentages, unit conversions, and date/time math
- 166+ fiat currencies, 21 cryptocurrencies with live exchange rates
- Variables, functions, and aggregates for quick iterative calculations
- Finance calculations (compound interest, ROI, loan repayment)
### Drawings
Sketch diagrams, wireframes, and whiteboard ideas on an [Excalidraw](https://excalidraw.com)-powered canvas next to your snippets and notes.
- Searchable list of drawings with keyboard navigation
- Pan and zoom remembered per drawing, with fit-to-content to recenter
- Export drawings as images
- Embed drawings directly in your markdown notes
### Developer Tools
Built-in utilities for the small tasks that usually send you to a browser tab:
- **Compare:** JSON Diff
- **Text:** Case Converter, Slug Generator, URL Parser, Line Break Normalizer
- **Crypto:** Hash/HMAC Generator, Password Generator, UUID
- **Encoders:** URL, Base64, JSON to TOML/XML/YAML, Color Converter
- **Generators:** JSON Generator, Lorem Ipsum
### Command Palette
Jump to spaces, snippets, notes, HTTP requests, and common actions from anywhere with a keyboard-first command palette.
- Open with <kbd>Cmd+P</kbd> on macOS or <kbd>Ctrl+P</kbd> on Windows and Linux
- Search across snippets, notes, HTTP requests, spaces, and commands
- Run create actions for snippets, notes, HTTP requests, and folders
- Scope search to a space with `@` or open command mode with `>`
### Imports
Bring existing work into your vault with preview-first imports for snippets, notes, and API collections.
- Import snippets from VS Code, Raycast, SnippetsLab, and public GitHub Gists
- Import markdown notes from Obsidian folders
- Import HTTP collections from OpenAPI, Postman, and Bruno
- Review detected items, folders, tags, environments, and warnings before writing anything
### Browser Clipper
Save web content from Chrome, Firefox, or Safari into the local massCode app.
- Install the Chrome version from the [Chrome Web Store](https://chromewebstore.google.com/detail/masscode-clipper/fkaaogdifollkhjbfoabbiocecehaaii)
- Save selected code as snippets
- Save selected text or readable page content as notes
- Save pages or links as HTTP `GET` requests
- Connect through the local Integration API with an API token
### AI Assistant
Ask the built-in assistant to carry out tasks across Code, Notes, and HTTP using your own AI provider account or a local model.
- Edit and format snippets, organize notes, and update tasks
- Find records across your vault and use them in a conversation
- Run HTTP collections with confirmation, explain failed checks, and save reports in Notes
- Request a preview before edits, adjust a task while it runs, and undo changes that support Undo
Cloud providers receive the context used for the task; use a model running on your computer for local processing. See the [AI Assistant guide](https://masscode.io/documentation/ai/) for setup and examples.
### MCP Integration
Connect Claude Code, Codex, Cursor, or VS Code Copilot to your massCode vault through the built-in MCP server.
- Find and read snippets, notes, and saved HTTP requests from your coding agent
- Save snippets and notes to folders with tags, and update them with protection against overwriting newer changes
- Organize folders, move items, and send them to Trash or restore them when you allow changes to existing items
- Organize and edit HTTP requests in collections
- Preview and send requests using the active massCode environment, then inspect saved execution history
See the [MCP setup guide](https://masscode.io/documentation/mcp/) to connect your agent.
## Markdown Vault
Your snippets, notes, and HTTP requests live as plain `.md` files on disk with frontmatter metadata, so the data stays readable and portable.
- **Git-friendly** - track changes and sync via any Git remote
- **Cloud sync** - works with iCloud, Dropbox, Google Drive, Syncthing
- **Live sync** - massCode watches the vault and picks up external changes in real time
- **No vendor lock-in** - your data is always yours
## Custom Themes
Customize the app UI and editor syntax highlighting with JSON theme files. Supports light and dark themes with live reload. See the [theme docs](https://masscode.io/documentation/themes.html).
## Contributions
massCode accepts external pull requests only for localizations and new syntax highlighting languages. To report a bug, please [open an issue](https://github.com/massCodeIO/massCode/issues/new/choose). For feature requests and ideas, start a discussion in [GitHub Discussions](https://github.com/massCodeIO/massCode/discussions).
See [CONTRIBUTING.md](CONTRIBUTING.md) for details.
## Build Locally
<details>
<summary>Instructions for building from source</summary>
### Prerequisites
- Node.js (>=20.16.0)
- pnpm (>= 9.0.0)
### Install Dependencies
```bash
pnpm install
```
### Build
To build for current platform:
```bash
pnpm build
```
To build for a specific platform:
```bash
pnpm build:mac # macOS
pnpm build:win # Windows
pnpm build:linux # Linux
```
### Development
To run in development mode:
```bash
pnpm dev
```
</details>
## Follow
- News and updates on [X](https://x.com/anton_reshetov)
- [Discussions](https://github.com/massCodeIO/massCode/discussions)
## License
[AGPL-3.0](https://github.com/massCodeIO/massCode/blob/master/LICENSE)
Copyright (c) 2019-present, [Anton Reshetov](https://github.com/antonreshetov).