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In order to run your new application, you must first build it using Gaudi compiler.

The Gaudi compiler not only checks the syntax of source files but also performs a complete static analysis of your application. It verifies model names, fields, identifier types, expressions, queries, and much more. This step helps identify many potential problems and bugs as early as possible.

If all checks pass without issues, the Gaudi compiler will produce a "definition" file, which essentially provides an abstract description of your application. This "definition" file serves as an input for the Gaudi runtime, which brings your application to life.

To execute the Gaudi compiler, use Gaudi CLI in your project directory.

npx gaudi build


Gaudi runtime is a Node.js based backend runtime that takes a "definition" file produced by the Gaudi compiler and runs your application.

Gaudi can be run as a standalone server or be integrated into an existing Node.js application. Currently, Gaudi supports express web server.

Standalone server

Gaudi comes with an embedded express server and if you're developing a pure Gaudi application, you can simply start your application via the CLI.

npx gaudi start

Environment variables

The following variables can be used to customize an embedded server:

GAUDI_DIRECTORY_NAME"gaudi"name of directory where Gaudi stores generated files that should be stored in version control (eg. database migration files)
GAUDI_DATABASE_URL-database connection string
GAUDI_RUNTIME_OUTPUT_PATH"dist"output path for generated files which should not be stored in a version control
GAUDI_RUNTIME_DEFINITION_PATHGAUDI_RUNTIME_OUTPUT_PATH + "/definition.json"path to a definition file
GAUDI_CORS_ORIGIN"" (disables CORS support)a list of domains which support CORS support - use "*" to support any domain

Embedded Gaudi

If you're already developing your Node.js application and want to embed Gaudi and develop other parts of your application within it you can use useGaudi express middleware provided by the gaudi package

import { useGaudi } from "@gaudi/runtime";

const app = express();

const config = {
outputDirectory: "dist",
definitionPath: "dist/definition.json",
dbConnUrl: process.ENV.GAUDI_DATABASE_URL,
cors: { origin: true },

// embed Gaudi in root path "/"

// embed Gaudi in subpath "/gaudi"
// app.use("/gaudi", useGaudi(config));

app.listen(3001, "localhost", () => {
console.log(`Gaudi app is started ...`);

Using with Gaudi CLI

Gaudi CLI dev command automates common development tasks (e.g. file compilation, copying static resources, watching for changes, ...) which gives you a smoother dev experience. By default, it uses internal express application which cannot be extended by developers. To use your own application server and still benefit from Gaudi CLI's automation, you can give CLI the path to your application script and Gaudi will use it instead of the default one.

npx gaudi dev --runtimePath=./dist/my_server.js

If you have other resources that affect runtime, e.g. if you compile your server or hooks from TypeScript to JavaScript or copy other files to output folder, you can include those files into Gaudi's watched resources list so it can reload you application when those files are changed as well.

npx gaudi dev --runtimePath=./dist/my_server.js --watch=.dist/*.js  --watch=.dist/other_config.json

Database access

Application needs a database connection in order to run. Database access is configured as an environment variable GAUDI_DATABASE_URL located in .env so make sure this matches your database configuration.