Show HN: Vibemail – AI-powered MJML email editor that runs in the browser

Hi HN! I built VibeMail, an email template editor that combines MJML with Claude AI to make creating (vibing) responsive HTML emails actually enjoyable.

The interesting bits:

- Three-panel layout: Monaco code editor, live preview, and Claude chat side-by-side

- AST-based code navigation: double-click text in the preview to jump to the exact line in the editor

- Multiple AI "agents" with full conversation rollback (inspired by Cursor's chat history)

- Project/email organization with a file-system-like structure

- Everything runs locally – your API key and templates never leave your browser

- I built the whole thing in a day: maybe 5hrs. Simon Willison is onto something with the personal software thing.

Tech stack: React, Vite, TypeScript, Zustand, MJML, Monaco Editor, and Claude Sonnet.

Fun fact: I prototyped the entire thing in ~10 minutes using Cursor and Claude Sonnet 4.5, which was a fun experiment in AI-assisted development. The hardest part was getting the AST parsing right for the code navigation feature.

Open to feedback!