Centina

Centina is an agentic canvas where everything you draw is real HTML and CSS. Flex wrapping, grid tracks, minmax(), fr units: behavior on the canvas is production behavior, because it is just the web.

Almost everything in Centina on the canvas is exposed via MCP so your agents can interact directly with it and derive context from it. Guidelines, grids, compass measurements, CSS properties, content, context, typefaces. All are exposed.

Centina is made in the spirit of the early web — in the spirit of early CSS, which treated the web as a new print medium. As such, it makes every effort to make typography, hierarchy, and alignment intuitive, obvious, and effortless.

Centina is designed in the spirit of “done” software. There's a problem to solve, and once the problem is solved we are finished. It is made with a single dependency, SolidJS. Because it is the web, it will not degrade — there are no forces behind the scenes, no web of dependencies forcing change where there is no need. The whole app is ~37,000 lines across ~200 files, and ships at less than 200kB over the wire via CDN — 622kB uncompressed. And it stays fast at scale: on a 200-screen mockup (~8,200 DOM elements — larger than most real design files), every interaction — pan, zoom, hover, select, drag, marquee — runs at ~120fps, maxed out.

There is no cloud — no shared database holding all users' information, with the need to address tenancy, compliance, migration, and maintenance that comes with it. You're free to host it on-prem or on your local computer, and all the data stays with you. Canvases are imported and exported as JSON documents, so you're free to manage your files however you choose — and version control them.

And best of all, Centina is free.