UI editor

Full-code apps can be created and edited directly in the Windmill web interface, without using the Windmill CLI.

Full-code apps

Overview

The in-browser editor provides:

File tree: navigate and manage frontend files
Code editor: edit frontend and backend code with syntax highlighting
Runnables panel: create, edit and configure backend runnables from a sidebar
Data table configuration: whitelist data tables from the UI
Preview: test your app without deploying

Creating a full-code app

From your Windmill home page:

Click New and select App (full-code) to start from scratch, then choose your framework (React or Svelte).
To start from an existing project instead, hover App (full-code) in the New popover and click Import full-code app, then paste your YAML or JSON export in the drawer.

Editing frontend files

The file tree on the left shows all frontend files. Click a file to open it in the code editor. You can:

Create new files and folders
Rename and delete files
Edit code with syntax highlighting and autocompletion

Managing backend runnables

The runnables panel on the right lists all backend runnables. From here you can:

Add new inline scripts in any supported language
Reference existing workspace scripts or flows
Configure static input fields
View and edit runnable code

Data table configuration

Configure which data tables your app can access:

Open the data configuration panel
Select a datatable from your workspace
Whitelist specific tables
Optionally set a schema name

Preview and testing

Click the preview button to test your app in the browser. The preview runs your bundled frontend code and connects to Windmill's backend for runnable execution.

In an AI session, the AI can read the preview's rendered DOM, console logs and job runs to debug the app, and you can click elements in the preview to attach them to your chat message. The AI can also capture the preview with its take_screenshot tool (Google Chrome only), and you can drag screenshots into the chat as image attachments.

When to use the UI editor vs CLI

Scenario	Recommended
Quick edits to an existing app	UI editor
New app from scratch	CLI (`wmill app new`)
Complex frontend with many dependencies	CLI (`wmill app dev`)
Team collaboration with git	CLI + git sync