Config

kirbyup.config.js in the project root configures both build and dev. The file is loaded with c12, so .ts, .mjs and .js all work. Neither .kirbyuprc nor a package.json key is read.

// kirbyup.config.js
import { defineConfig } from 'kirbyup/config'

export default defineConfig({
  alias: {},
  vite: {},
})

defineConfig(config)

Returns config unchanged. It exists for type hints and autocompletion.

alias

• Type: AliasOptions from Vite

Extra import aliases, merged after the built-in ~/ and @/. An object maps a prefix to a replacement, an array of { find, replacement } entries allows regular expressions. Entries apply in order, the first match wins.

Absolute paths resolve on the file system. Relative values are passed through as written, which is rarely what you want.

vite

• Type: InlineConfig from Vite

Merged into kirbyup's own config with Vite's mergeConfig. Arrays such as plugins are appended, everything else overrides.

kirbyup sets these options. Overriding the ones marked as fixed breaks the output.

Option	kirbyup default	Notes
resolve.alias	~/ and @/ to the entry file's folder	Extend via alias
plugins	Vue, Vue JSX, auto-imports	Yours are appended. Vue and Vue JSX treat the Panel's k-validator and k-input-validator as custom elements.
envPrefix	['VITE_', 'KIRBYUP_']	See Env Variables
build.lib	ES module from the entry file	Fixed
build.rolldownOptions.external	['vue']	Fixed, vue comes from the Panel
build.rolldownOptions.output.codeSplitting	false	Fixed, Kirby serves no script beside index.js or index.dev.js
build.minify	true for production, false for watch builds	With Vite's own minifier, kirbyup also sets build.rolldownOptions.output.minify, which Vite's library mode leaves without whitespace removal. Set it yourself to override. 'esbuild' keeps the whitespace.
build.target	The browsers the Kirby Panel supports	Yours replaces it
server.port	--port, default 5177	Config wins over the flag
server.origin	Derived from server.host, server.https and the port	The URL written into index.dev.js
server.strictPort	true	Fails instead of picking another port
server.cors	true	The Panel runs on another origin

Set server.origin when the Panel cannot reach the dev server under the derived URL, for example on another host or behind a proxy.