masscode

massCode is a free, open-source desktop application that positions itself as a developer workspace rather than only a snippet manager. It runs on macOS, Windows and Linux, and keeps user data local: snippets, notes and HTTP requests are stored as plain `.md` files with frontmatter metadata in a vault directory. Main capabilities described in the README: - **Code snippets**: multi-level folders, tags and fragments; 160+ syntax grammars out of the box (600+ via `.tmLanguage`); integrated Prettier formatting; real-time HTML/CSS preview; a JSON visualizer; and export of snippets as themed images. - **Notes**: Markdown documents with editor, live preview and preview modes; task notes with status, priority and due dates plus Today/Upcoming/Completed views; editable Markdown tables; internal links between notes, snippets and HTTP requests; note inspector with section navigation; Mermaid diagrams; mind maps from heading structure; presentation mode; callouts and image embedding; a notes graph and dashboard. - **HTTP client**: HTTP, GraphQL and WebSocket requests; collections and nested folders with shared auth, headers, variables and scripts; environments and local secret variables; assertions and JavaScript tests; sequential collection runs; request code generation for 20 languages/runtimes; response inspection, history, console debugging and cookie management; imports from OpenAPI, Postman and Bruno. - **Math notebook**: natural-language arithmetic, percentages, unit conversions and date/time math; 166+ fiat currencies and 21 cryptocurrencies with live rates; variables, functions and aggregates; finance calculations such as compound interest, ROI and loan repayment. - **Drawings**: an Excalidraw-powered canvas with searchable drawing list, per-drawing pan/zoom memory, image export and embedding in Markdown notes. - **Developer tools**: JSON diff, case converter, slug generator, URL parser, line-break normalizer, hash/HMAC generator, password generator, UUID, URL/Base64 encoders, JSON to TOML/XML/YAML conversion, color converter, JSON generator and Lorem Ipsum. - **Command palette**: keyboard-first navigation and search across snippets, notes, HTTP requests, spaces and commands, with `@` space scoping and `>` command mode. - **Imports**: preview-first imports of snippets from VS Code, Raycast, SnippetsLab and public GitHub Gists; Markdown notes from Obsidian folders; HTTP collections from OpenAPI, Postman and Bruno. - **Browser clipper**: Chrome, Firefox and Safari extensions to save selected code as snippets, text or readable page content as notes, and pages or links as HTTP GET requests, connecting through a local Integration API with a token. - **MCP integration**: a built-in MCP server lets coding agents such as Codex, Claude Code, Cursor or VS Code Copilot find and read snippets, notes and saved HTTP requests, save new items to Inbox, and send saved requests using the active environment. Because the vault is plain Markdown, the README notes it is Git-friendly, can sync through iCloud, Dropbox, Google Drive or Syncthing, supports live watching of external changes, and avoids vendor lock-in. Custom JSON theme files can adjust the app UI and editor syntax highlighting, with light and dark themes and live reload. Building from source requires Node.js >= 20.16.0 and pnpm >= 9.0.0, with `pnpm install`, `pnpm dev`, and platform-specific `pnpm build:mac`, `pnpm build:win` or `pnpm build:linux` commands. The project is licensed under AGPL-3.0 and is maintained by Anton Reshetov.