Code Snippets

Build a reusable code library across projects and languages. Organize snippets with folders, tags, and fragments, then edit them with CodeMirror , format them with Prettier , preview HTML & CSS in real time, inspect JSON visually, and export polished screenshots when you need to share code.

Notes

Keep technical notes, task notes, docs, and drafts next to your snippets. Write in Markdown with live preview, add status, priority, and due dates to task notes, organize with folders and tags, and use Mermaid diagrams, mindmaps, or fullscreen presentation mode when you need more structure.

HTTP Client

Save and send API requests without leaving your workspace. Organize requests in folders, switch environments, preview outgoing HTTP or cURL, inspect responses, and import collections from OpenAPI, Postman, and Bruno.

Math Notebook

Do the quick calculations that usually break your flow. Natural-language math handles inputs like time in Tokyo, density of honey, and $500 invested $1,500 returned for currencies, time zones, unit conversion, finance, and date math.

Drawings

Sketch diagrams, wireframes, and whiteboard ideas on an Excalidraw -powered canvas. Keep a searchable list of drawings beside your snippets and notes, recenter with fit-to-content, export them as images, and embed drawings directly in your Markdown notes.

Developer Tools

Handle the small developer tasks that usually send you to a browser tab. Convert, encode, hash, and generate data right inside massCode with tools for JSON, Base64, URLs, colors, passwords, UUIDs, and more.

Imports

Bring existing libraries into your local vault. Import snippets from VS Code, Raycast, SnippetsLab, and public GitHub Gists, or import Obsidian markdown folders into Notes with a preview before writing.

Integrations

Bring your snippet library into the tools you already use. VS Code Extension for searching and inserting snippets, and Raycast Extension for quick access from anywhere.

Open & Local

Keep your data on your machine and in your control. Notes and snippets are stored as plain Markdown files, so syncing with iCloud, Dropbox, or Git stays simple and portable.

Localization

Use massCode in the language you are most comfortable with. The app is available in 15 languages, including English, Deutsch, Español, Français, Русский, 日本語, and 中文.