Today Canvas Kit
Toolkit for shipping a window-manager-of-widgets — host runtime, widget SDK, .tckb bundle format.
Today Canvas Kit (repo slug today-tck) is the toolkit behind Today Page: a host that mounts independent widgets and an SDK widgets compile against. Widgets ship as .tckb bundles — hash-addressable, freestanding ESM-plus-CSS envelopes. The same bundle runs in a browser host, a native WebView, or a preview shell.
This site is the canonical reference for the platform contract. Downstream specs (today-cloud, today-platform-web, native shells) link here rather than restating it.
Where to start
Building widgets
Scaffold a project, run the dev shell, build a .tckb. The quickest path from "I want to ship a widget" to a working bundle.
Platform ABI
The v1 wire-level contract — externals, host shared-deps, widget contract, versioning. The source of truth for everything else here.
.tckb wire format
Zip layout, hash format, integrity model. Cited by downstream specs.
SDK packages
Index of the eight published @todayai-labs/* packages, grouped by runtime category.
Get a host playground running
corepack enable
pnpm install
pnpm dev # http://localhost:5173 — workbench renders every workspace widget