# Sandbox — Postext

> Try the Postext typesetting engine live: edit markdown, manage figures and tables, tune Knuth-Plass justification, and export print-ready PDF and EPUB — in the browser.

- HTML version: https://postext.dev/en/sandbox
- Other languages: [es](https://postext.dev/es/sandbox.md), [ca](https://postext.dev/ca/sandbox.md), [de](https://postext.dev/de/sandbox.md), [fr](https://postext.dev/fr/sandbox.md), [it](https://postext.dev/it/sandbox.md), [pt](https://postext.dev/pt/sandbox.md), [zh](https://postext.dev/zh/sandbox.md), [ja](https://postext.dev/ja/sandbox.md), [ar](https://postext.dev/ar/sandbox.md)

Interactive in-browser editor: write markdown, tune the configuration and export print-ready PDF and EPUB 3 e-books.

- [Sandbox](https://postext.dev/en/docs/sandbox.md): The Sandbox's interface: the activity bar and the Text, Books, Chapters, Resources and Fonts panels, and the layout on phones
- [postext-guide.postext](https://postext.dev/bundles/postext-guide.postext): the Postext guide as one .postext file (manifest, Markdown chapters, fonts and pictures)
- WebMCP tools: in a browser with WebMCP (document.modelContext) every page registers tools for an agent — search, read a page as Markdown, open a Cookbook recipe in the Sandbox — and the Sandbox adds its own (sandbox_*): read and edit the book, change any design setting, get any laid-out page as a JPEG, turn pages, switch viewer, export