A free, open-source developer workspace.
Snippets, notes, HTTP requests, calculations, drawings, and dev tools in one local-first app.
Your data stays on your machine as plain Markdown files.
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Available for macOS, Windows, and Linux
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## 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 - 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 and image embedding ### HTTP Client Keep API requests close to your code snippets and project notes with a lightweight HTTP client built into massCode. - Organize requests with folders and custom folder icons - Use environments and `{{variables}}` for local, staging, and production APIs - Edit params, headers, body, auth, and markdown descriptions - Preview requests as raw HTTP or cURL before sending - Inspect response status, time, size, body, and headers - Send the current request with Cmd+Enter on macOS or Ctrl+Enter on Windows and Linux ### 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 Cmd+P on macOS or Ctrl+P 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 ## 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). ## Build Locally