Full-code apps

Full-code apps let you build custom frontends with React or Svelte that connect to Windmill backend runnables and data tables. Unlike the low-code app editor, you write your own components and have full control over the UI.

Full-code apps

How it works

A full-code app is a directory with the .raw_app suffix (e.g. my_app.raw_app/) or the __raw_app suffix (e.g. my_app__raw_app/) depending on your sync settings. It contains:

Frontend code: React or Svelte components bundled and served by Windmill
Backend runnables: scripts in any supported language that run on Windmill workers
Configuration: a raw_app.yaml file defining metadata, policy and data access

When deployed, Windmill bundles your frontend code and serves it as a single-page application. Your frontend calls backend runnables through an auto-generated wmill.ts module, which communicates with Windmill's execution engine via WebSocket.

Full-code vs low-code apps

Low code apps are built with the low-code app editor, while full-code apps are built with React or Svelte.

	Full-code apps	Low-code apps
UI	Custom React/Svelte components	Drag-and-drop component library
Frontend logic	Full framework features (hooks, stores, routing)	Connecting components + inline scripts
Backend	Scripts in `backend/` folder, any language	Runnables panel, inline or workspace scripts
Styling	Your own CSS, Tailwind, etc.	Component-level + global CSS editor
Local dev	`wmill app dev` with hot reload	Web-based editor only
Best for	Custom UIs, complex interactions, existing codebases	Quick dashboards, forms, CRUD interfaces

Low-code apps

Build apps with drag-and-drop components and inline scripts.

Getting started

For a step-by-step tutorial building a complete app, see the full-code apps quickstart.

Full-code apps quickstart

Step-by-step guide to build your first full-code app.

Platform

The full-code apps are built on the Windmill platform, which provides a backend for running your code and a frontend for building your UI.

Just hit '+ App' and select 'Full-code App'.

Choose app builder

Then pick a framework (React or Svelte), a Data configuration (optional) and a name for your app. Optionally, you can start it with AI.

New app setup

UI editor

Edit full-code apps in the browser.

Locally

The fastest way to create a full-code app is with Windmill CLI:

wmill app new

This scaffolds a project with your chosen framework (React or Svelte), a sample backend runnable, and the necessary configuration. Then start the development server:

cd f/folder/my_app.raw_app   # or my_app__raw_app
wmill app dev .

See the CLI workflow page for the full setup guide.

CLI workflow

Scaffold and develop full-code apps from your terminal.

Folder suffix

By default the CLI uses dotted suffixes (.raw_app). If your filesystem or tooling hides dotfiles, set nonDottedPaths: true in your wmill.yaml to use dunder suffixes (__raw_app) instead. All examples in this documentation use the default .raw_app suffix — substitute __raw_app if you enabled non-dotted paths.