The live editor

ezu serve                                                # the default example style
ezu serve crates/ezu/examples/styles/pencil-sketch.json  # a local file
ezu serve https://example.com/style.json                 # or fetch one
# → http://127.0.0.1:8080

The editor is a MapLibre GL page with the style JSON beside the map. Hit ⌘↵ / Ctrl+↵ to apply, or turn on Live preview to apply on every keystroke that parses, schema-validates, and builds clean.

What the server exposes

Route	Serves
/	the editor
/tiles/{z}/{x}/{y}.png · .webp	rendered tiles — a usable tile source for any client
/mvt/{z}/{x}/{y}	the raw MVT bytes behind the current tile
/schemas/ezu-style.json	the JSON Schema, assembled from the registered ops
/style/params	the current style’s parameter schema
/style/attribution	merged attribution across the document and its sources

The tile route takes param overrides as query string values, which is how the params panel re-renders without touching the style text:

curl 'http://127.0.0.1:8080/tiles/13/7276/3225.png?paper=%23ffe0f0&softness=2'

Editing features worth knowing

• Params panel — controls generated from the style’s params block: sliders for bounded numbers, colour pickers, toggles. reset returns to the declared defaults. Each colour has a hex field beside its swatch, so a value can be pasted in from anywhere it was picked and copied back out — clicking the field selects it. CSS shorthand is understood on the way in (#fff, #fffa, and either without the #) and expanded to the #rrggbb / #rrggbbaa the spec speaks. The field is also where alpha lives, since the native picker cannot show it.
• External-edit reload — launched with a local path, the server watches the file and pushes Server-Sent Events on change. Edit in your own editor and the browser follows; with unsaved edits in the buffer you get a Reload banner instead of a silent swap.
• Open / URL / Save — load from a local file or an http(s) URL. On Chromium the File System Access API lets Save write back in place.
• Source MVT inspector — overlay the underlying vector tile, toggle layers, click a feature to read its properties. Indispensable when writing a filter-expr and wondering what the data actually says.
• Tile grid — a z/x/y boundary overlay, which is how you check that dabs and labels really are continuous across edges.

Validation in the editor is the same validation ezu check runs, and the schema it validates against is derived from the registry — so custom ops get completion and error squiggles with no extra work.

Serving to something other than the editor

ezu serve is a real tile server, so during development you can point an existing MapLibre or Leaflet app at http://127.0.0.1:8080/tiles/{z}/{x}/{y}.png and see your style in place. For anything beyond development, see serve tiles.

The ezu-wasm demo page ships here too, including the COOP/COEP headers the threads build needs — see use in the browser.