Config

Deckup loads one configuration file from the project root. Supported filenames are:

• deckup.config.ts
• deckup.config.js
• deckup.config.mjs
• deckup.config.mts
• deckup.config.cjs
• deckup.config.cts

The configuration file must default-export an object. Only one supported config file can exist in a project; Deckup reports an error when it finds more than one.

Use defineConfig() for type checking and editor completion:

import { defineConfig } from "deckup";

export default defineConfig({
  port: 4321,
  theme: "google-basic",
  integrations: {
    tailwind: {
      optimize: { minify: false },
    },
  },
  astro: {
    vite: {
      resolve: {
        alias: { "@slides": "/absolute/path/to/slides" },
      },
    },
  },
});

Options

port

Set the default port used by deckup open:

export default defineConfig({
  port: 3000,
});

The --port CLI option takes precedence over this value. When neither is set, Deckup uses port 4321.

theme

Set the fallback theme used when a deck does not declare one in its static metadata:

export default defineConfig({
  theme: "minimal",
});

Deck metadata takes precedence over this value. When neither is set, Deckup uses default. See the Theme reference for built-in, installed, and registry themes.

integrations

Deckup provides built-in integrations that are configured separately from Astro integrations. Tailwind CSS v4 is currently the only built-in integration.

integrations.tailwind

Tailwind is enabled when integrations.tailwind is omitted, so Astro and MDX decks can use utility classes without installing packages or importing CSS. Pass an @tailwindcss/vite options object to configure its Vite plugin:

export default defineConfig({
  integrations: {
    tailwind: {
      optimize: { minify: false },
    },
  },
});

Set it to false to remove Deckup’s built-in Tailwind plugins and generated stylesheet:

export default defineConfig({
  integrations: {
    tailwind: false,
  },
});

Built-in plugins run before plugins from astro.vite.plugins. Manual Tailwind plugins in that list are not de-duplicated. This option applies to the Deckup CLI; projects that host @deckup/astro configure styling in their own Astro setup.

astro

Use astro to pass supported Astro inline configuration to Deckup. For example, install and register an Astro integration:

import react from "@astrojs/react";
import { defineConfig } from "deckup";

export default defineConfig({
  astro: {
    integrations: [react()],
  },
});

Deckup owns the Astro options required to provide the slide runtime and consistent development and build behavior. The following fields are therefore not available under astro:

• root
• srcDir
• configFile
• output
• server
• outDir
• logLevel
• devToolbar

Nested astro.vite.root is ignored as well. Use the Deckup CLI options for server and output settings. See the React and Vue guides for complete integration examples.