massCodeYour developer workspace

Manage code snippets, write markdown notes, solve calculations, and use built-in developer tools. Free, open source, and works offline.

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, docs, and drafts next to your snippets. Write in Markdown with live preview, folders, tags, Mermaid diagrams, mindmaps generated from headings, and fullscreen presentation mode for sharing your work.

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.

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.