Azure Static Web Apps CLI (preview)

The Static Web Apps CLI, also known as SWA CLI, serves as a local development tool for Azure Static Web Apps. It can:

• Serve static app assets, or proxy to your app dev server
• Serve API requests, or proxy to APIs running in Azure Functions Core Tools
• Emulate authentication and authorization
• Emulate Static Web Apps configuration, including routing

Static Web Apps CLI is in preview. If you have suggestions or you encounter issues, please report them or help us fix them. Your contributions are very much appreciated. 🙏

The CLI emulates commonly used capabilities of the Azure Static Web Apps cloud service. Some differences are expected. Always deploy and test your apps in Azure to confirm behavior.

Quickstart

Using npm or yarn:

• Install the cli

  npm install -g @azure/static-web-apps-cli
  

• Open a SWA app folder at the root (outside any /api or /app folders):

  cd my-awesome-swa-app
  

• Start the emulator:

  swa start ./
  

• Access your SWA app from http://localhost:4280

Note: The cli can also be installed locally as a devDependency: npm install -D @azure/static-web-apps-cli

Using npx:

• Open a SWA app folder at the root (outside any /api or /app folders): cd my-awesome-swa-app
• Start the emulator: npx @azure/static-web-apps-cli start
• Access your SWA app from http://localhost:4280

Start the emulator

Serve from a folder

By default, CLI starts and serves any the static content from the current working directory ./:

swa start

However, you can override this behavior. If the artifact folder of your static app is under a different folder (e.g. ./my-dist), then run the CLI and provide that folder:

swa start ./my-dist

Serve from a dev server

When developing your frontend app locally, it's often useful to use the dev server that comes with your frontend framework's CLI to serve your app content. Using the framework CLI allows you to use built-in features like the livereload and HMR (hot module replacement).

To use SWA CLI with your local dev server, follow these two steps:

1. Start your local dev server (as usual). For example, if you are using Angular: ng serve
2. In a separate terminal, run swa start with the URI provided by the dev server, in the following format:

   swa start http://<APP_DEV_SERVER_HOST>:<APP_DEV_SERVER_PORT>
   

Here is a list of the default ports used by some popular dev servers:

Tool	Port	Command
Angular	4200	swa start http://localhost:4200
Blazor WebAssembly	5000	swa start http://localhost:5000
Gatsby	8000	swa start http://localhost:8000
Hugo	1313	swa start http://localhost:1313
Next.js	3000	swa start http://localhost:3000
React (Create React App)	3000	swa start http://localhost:3000
Svelte (sirv-cli)	5000	swa start http://localhost:5000
Vue	8080	swa start http://localhost:8080

Instead of starting a dev server separately, you can provide the startup command to the CLI.

# npm start script (React)
swa start http://localhost:3000 --run "npm start"

# dotnet watch (Blazor)
swa start http://localhost:5000 --run "dotnet watch run"

# Jekyll
swa start http://localhost:4000 --run "jekyll serve"

# custom script
swa start http://localhost:4200 --run "./startup.sh"

Go to 4280 (http://localhost:4280) to access the application with the emulated services.

Serve both the static app and API

If your project includes API functions, install Azure Functions Core Tools:

npm install -g azure-functions-core-tools@3 --unsafe-perm true

Start API server automatically

Run the CLI and provide the folder that contains the API backend (a valid Azure Functions App project):

# static content plus API
swa start ./my-dist --api-location ./api-folder

# frontend dev server plus API
swa start http://localhost:3000 --api-location ./api-folder

Start API server manually

When developing your backend locally, sometimes it's useful to run Azure Functions Core Tools separately to serve your API. This allows you to use built-in features like debugging and rich editor support.

To use the CLI with your local API backend dev server, follow these two steps:

1. Start your API using Azure Functions Core Tools: func host start or start debugging in VS Code.
2. In a separate terminal, run the SWA CLI with the --api-location flag and the URI of the local API server, in the following format:

   swa start ./my-dist --api-location http://localhost:7071
   

Use a configuration file (staticwebapp.config.json)

Azure Static Web Apps can be configured with an optional staticwebapp.config.json file. For more information, see Configure Static Web Apps documentation.

If you are serving static files from a folder, the CLI will search this folder for staticwebapp.config.json.

# ./my-dist is searched for staticwebapp.config.json
swa start ./my-dist

If you are using a frontend dev server, the CLI will search the current directory for staticwebapp.config.json.

# current working directory is searched for staticwebapp.config.json
swa start http://localhost:3000

To control where the CLI searches for staticwebapp.config.json, use --swa-config-location.

# static files
swa start ./my-dist --swa-config-location ./my-app-source

# frontend dev server
swa start http://localhost:3000 --swa-config-location ./my-app-source

Configuration

If you need to override the default values, provide the following options:

Options	Description	Default	Example
--app-location	set location for the static app source code	./	--app-location="./my-project"
--api-location	set the API folder or dev server		--api-location="./api" or --api-location=http://localhost:8083
--swa-config-location	set the directory of the staticwebapp.config.json file.		--swa-config-location=./my-project-folder
--api-port	set the API server port	7071	--api-port=8082
--host	set the emulator host address	0.0.0.0	--host=192.168.68.80
--port	set the emulator port value	4280	--port=8080
--ssl	serving the app and API over HTTPS (default: false)	false	--ssl or --ssl=true
--ssl-cert	SSL certificate to use for serving HTTPS		--ssl-cert="/home/user/ssl/example.crt"
--ssl-key	SSL key to use for serving HTTPS		--ssl-key="/home/user/ssl/example.key"
--run	Run a command at startup		--run="cd app & npm start"
--devserver-timeout	The time to wait(in ms) for the dev server to start	30000	--devserver-timeout=60000
--func-args	Additional arguments to pass to func start		--func-args="--javascript"
--config	Path to swa-cli.config.json file to use.	./swa-cli.config.json	--config ./config/swa-cli.config.json
--print-config	Print all resolved options. Useful for debugging.		--print-config or --print-config=true
--open	Automatically open the SWA dev server in the default browser.	false	--open or --open=true

swa-cli.config.json file

The CLI can also load options from a swa-cli.config.json file.

{
  "configurations": {
    "app": {
      "context": "http://localhost:3000",
      "apiLocation": "api",
      "run": "npm run start",
      "swaConfigLocation": "./my-app-source"
    }
  }
}

If only a single configuration is present in the swa-cli.config.json file, running swa start will use it by default. If options are loaded from a config file, no options passed in via command line will be respected. For example swa start app --ssl=true. The --ssl=true option will not be picked up by the CLI.

Example

We can simplify these commands by putting the options into a config file.

# static configuration
swa start ./my-dist --swa-config-location ./my-app-source

# devserver configuration
swa start http://localhost:3000 --swa-config-location ./my-app-source

{
  "configurations": {
    "static": {
      "context": "./my-dist",
      "swaConfigLocation": "./my-app-source"
    },
    "devserver": {
      "context": "http://localhost:3000",
      "swaConfigLocation": "./my-app-source"
    }
  }
}

These configurations can be run with swa start static and swa start devserver.

Validation

You can validate your swa-cli.config.json with a JSON Schema like so:

{
  "$schema": "https://raw.githubusercontent.com/Azure/static-web-apps-cli/main/schema/swa-cli.config.schema.json",
  "configurations": {
    ...
  }
}

Local authentication & authorization emulation

The CLI allows you to mock and read authentication and authorization credentials.

Mocking credentials

When requesting the Static Web Apps login endpoints (http://localhost:4280/.auth/login/<PROVIDER_NAME>), you have access to a local authentication UI. This interface is served locally from the emulator and allows you to set fake user information for the current user from the provider supplied.

Reading credentials

The frontend application can request the http://localhost:4280/.auth/me endpoint and a clientPrincipal containing the fake information will be returned by the authentication API.

Here is an example:

{
  "clientPrincipal": {
    "identityProvider": "twitter",
    "userId": "<USER-UUID>",
    "userDetails": "<USER_NAME>",
    "userRoles": ["anonymous", "authenticated"]
  }
}

The API functions can access user information using the x-ms-client-principal header.

See Accessing user information documentation for more details.

High-level architecture

The SWA CLI is built on top of the following components:

• A Reverse Proxy is the heart of the SWA CLI; it's the piece that forwards all HTTP requests to the appropriate components:
  • /.auth/** requests are forwarded to the Auth emulator server.
  • /api/** requests are forwarded to the localhost API function (if available).
  • /** all other requests are forwarded to the static assets server (serving the front-end app).
• The Auth emulator server emulates the whole authentication flow.
• The Static content server serves the local app static content.
• The Serverless API server is served by Azure Functions Core Tools.

Want to help?

Want to file a bug, contribute some code, or improve the documentation? Excellent! Read up on our guidelines for contributing and then check out one of our issues in the list: community-help.