Playground

You can edit → compile → preview Kumiki in the browser. The compiler (@kumikijs/compiler) and runtime (@kumikijs/runtime) run inside the browser. Edit on the left and the result appears on the right. From Choose an example… you can load each example from the feature catalog.

Choose an example…01-slot-and-reducer.kumiki02-nominal-type.kumiki03-union-and-match.kumiki04-record-and-copy.kumiki05-pure-fn.kumiki06-if-expression.kumiki07-list.kumiki08-map.kumiki09-set.kumiki10-option.kumiki11-time-and-duration.kumiki12-layout.kumiki13-text-input-bind.kumiki14-select.kumiki15-checkbox.kumiki16-conditional-ui.kumiki17-theme.kumiki18-routing.kumiki19-effect-http.kumiki20-effect-storage.kumiki21-timer.kumiki22-result.kumiki23-lifecycle-route-enter.kumiki24-fold.kumiki25-stop-timer.kumiki26-overlay.kumiki27-custom-capability.kumiki28-tests.kumiki30-motion.kumiki31-argless-methods.kumiki32-panic-boundary.kumiki33-field-vs-method.kumiki34-builtin-tiles.kumiki35-match-and-args.kumiki36-effect-indexed-db.kumiki37-lifecycle-events.kumiki38-confirm-leave-guard.kumiki39-effect-session.kumiki40-nested-routes.kumiki40-token-refs.kumiki41-link-prefetch.kumiki42-scroll-restoration.kumiki43-file-upload-preview.kumiki44-episode-test.kumiki45-ui-key-hover-tuple.kumiki46-stdlib-paren-methods.kumiki47-icon-set.kumiki48-effect-cancel.kumiki49-ui-focus-blur.kumiki50-match-pattern-integrity.kumiki51-selector-id.kumiki52-selector-id-arg.kumiki53-keyed-list-identity.kumiki54-select-preserves-state.kumiki55-video-preserves-currenttime.kumiki56-details-preserves-open.kumiki57-editable-preserves-focus.kumiki58-unkeyed-conditional-rebuild.kumiki59-overlay-keyed-layers.kumiki60-empty-state-keyed-list.kumiki61-reserved-identifier-names.kumiki62-conditional-inline-tile-handlers.kumiki63-reducer-batch-atomicity.kumiki64-init-slot-argument.kumiki65-prefers-dark.kumiki66-value-types.kumiki67-self-reference.kumiki68-name-uniqueness.kumiki69-builtin-effect-capabilities.kumiki70-spec-grammar.kumiki71-button-type.kumiki72-time-format.kumiki73-effect-policy-queue.kumiki74-common-tile-props.kumiki75-paren-less-stdlib-constants.kumiki76-conditional-adds-a-universal-handler.kumiki77-int-float-math.kumiki…

# Feature: slot (state) + reducer (update) + tile (view) # The smallest possible state cycle. slot count : Int = 0 reducer inc on=ui.click(IncBtn) do= count := count + 1 tile IncBtn = button(text="+1", onClick=inc) tile App = column(heading("Count: " + count.show), IncBtn) app SlotAndReducer caps = [] routes = {"/" -> App, "/404" -> App} init = []

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WebMCP

For WebMCP-capable browsers/agents, this page exposes tools via navigator.modelContext.registerTool (effective only in supporting environments).

Tool	Purpose
kumiki_compile	Compiles the given Kumiki source and returns success/failure and diagnostics (read-only)
kumiki_list_examples	Returns the list of the playground's per-feature examples (read-only)
kumiki_load_example	Loads an example into the editor by name
kumiki_set_source	Replaces the editor's source and previews it

For local CLI / editor integration, there is also the @kumikijs/mcp server that runs over stdio.