App Configuration

A UIX app can be configured with 2 types of files: An app.dx file specifying general options for the entire app, and individual .dx files located in frontend or backend directories that specify options for the specific endpoints.

DATEX Script files (.dx)

UIX uses DATEX Script files as configuration files.

DATEX Script is a superset of JSON. It also supports URLs, relative paths and custom types. Single- and multiline comments can be used.


    normalJSON: [1, "text", {"a": "b"}],
    url: https://example.com, // this is a comment
    relativePath: ../my/file/path,
 This is a multiline comment

To learn more about DATEX Script, check out the DATEX docs.

The app.dx file

General Options

The following options provide some general information or behaviour of the app.

  • name: (text) - The name of the app
  • description: (text) - Short description for the app
  • icon: (text or url) - URL path to an app icon image - can also be a relative path, e.g. ./common/res/icon.png
  • installable: (boolean) - The app can be installed as standalone web app
  • meta: (Record<string,string>) - Custom <meta> tags (name and content) that are added to the HTML head on each page
  • manifest: Record<string,any> - Custom web manifest options that override the defaults set by UIX
  • experimental_features: string[] - List of experimental UIX features that should be enabled

Experimental Features

Experimental features are subject to change and might be enabled by default in future versions of UIX. To enable experimental features, add them to the experimental_features list in the app.dx file.

Available experimental features:

  • "embedded-reactivity": Enables compile-time reactivity features for JSX templates and the $() syntax
  • "protect-pointers": Sets the PROTECT_POINTERS DATEX Runtime flag, which disables pointer read/write access for remote endpoints per default. Backend exports and pointers returned from backend functions are still publicly accessible by all endpoints.
  • "indirect-references": Sets the INDIRECT_REFERENCES DATEX Runtime, which enables for indirect references to pointers from other pointers.
  • "frontend-navigation": Enables the new frontend navigation system, which allows for client-side routing without full page reloads.
  • "view-transitions": Enables CSS view transitions for backend navigations and frontend navigations (the "frontend-navigation" feature must be enabled to work with frontend navigations).


The paths for frontend, backend and shared (common) files can be explicitly set in the app.dx files. Per default, the frontend path is ./frontend/, the backend path is ./backend/ and the common path is ./common/.

  • frontend: (url or url[]) - Directory for frontend code
  • backend: (url or url[]) - Directory for backend code
  • common: (url or url[]) - Directory with access from both frontend end backend code
  • pages: (url or url[]) experimental! - Common directory with structural access from both frontend end backend code. File paths are automaticially mapped to app routes.

Example app.dx configuration

name: "My App",
description: "I made a thing",
icon: "https://example.org/icon.ico",
common: [./lib, ./common]; // multiple common paths

App Deployment Stages

UIX apps can be run in different stages. The names of the stages are not predefined and can be set as needed. (Exception: The default stage is called 'dev'.)

To run a UIX app in a specific stage, use the --stage options:

uix --stage production

Per default, running a UIX app in a different stage does not have any noticable effect.

The current stage can be accessed via app.stage:

import { app } from "uix/app/app.ts";
const stage = app.stage // "production"

In app.dx files, the #public.uix.stage helper function can be used to access the stage, enabling custom deployment configurations.

The .dx files

.dx files can be put in frontend or backend directories. A .dx configuration file in a backend directory is applied to the backend endpoint, a .dx file in a frontend directory is applied to each frontend endpoint.


Per default, a .dx config file can contain the following options:

  • endpoint: (endpoint) The endpoint that should be used for this directory
  • connect: (boolean) Connect to the supranet on start (default: true)
  • keys: (Crypto.ExportedKeySet) Set custom private + public keys for this endpoint

Additional options may be passed in for backend endpoints .dx configurations (See Deployment).

The "stage" helper function

To dynamically set options in the .dx configuration file depending on the current deployment stage, the #public.uix.stage helper function can be used:

use stage from #public.uix; // import the 'stage' helper function

endpoint: stage {
    dev:        @+my_app_dev,  // selected when running in 'dev' stage
    staging:    @+my_app_stag, // selected when running in 'staging' stage
    prod:       @+my_app_prod  // selected when running in 'prod' stage

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