Quickstart

wasmCloud enables you to build polyglot applications out of reusable WebAssembly (Wasm) components and run them everywhere—across any cloud, Kubernetes, datacenter, or edge.

In this tutorial:

• We'll use the wasmCloud Shell (wash) CLI to build a simple "Hello world" HTTP server application from a WebAssembly component—written in the language of your choice.
• Along the way, we'll start a developer loop that automatically deploys our application to a local wasmCloud environment.

Install wash

First, we need to install the latest version of wash.

On macOS, you can use Homebrew to install wash:

shell

brew install wasmcloud/wasmcloud/wash

On Ubuntu and Debian Linux, you can use apt to install wash:

shell

curl -s https://packagecloud.io/install/repositories/wasmcloud/core/script.deb.sh | sudo bash

shell

sudo apt install wash

On Windows, you can use Chocolatey to install wash:

shell

choco install wash

We support other package managers and the option to install from source. If you'd like to use a different installation method, see the Installation page.

Verify that wash is installed by running:

shell

wash --version

Choose your language

wasmCloud supports building WebAssembly components from any language that supports the WASI 0.2 target, including Go, Rust, TypeScript, and others.

wash depends on your local language toolchain for your language of choice.

• Choose the language you would like to use.
• Install the toolchain or verify that you have the correct versions.

Go

Install the Go toolchain

Requirements:

• Go 1.23.0+
• TinyGo 0.33.0+:
• wasm-tools

On macOS or Linux, you can use Homebrew to install the Go toolchain:

shell

brew install go

shell

brew install tinygo

You will also need to download the binary for the latest version of wasm-tools for your architecture and add it to your PATH.

On Windows, you can use Scoop to install the Go toolchain (as well as the binaryen tool to compile components on Windows):

shell

scoop install go

shell

scoop install tinygo

shell

scoop install binaryen

You will also need to install the latest version of wasm-tools and add it to your PATH.

Rust

Install the Rust toolchain

Requirements:

• The Rust toolchain
• The wasm32-wasip2 target for Rust

On macOS or Linux, you can use the official install script to download rustup, which will automatically install the Rust toolchain:

shell

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

Once you've installed the Rust toolchain, use rustup to add the wasm32-wasip2 target:

shell

rustup target add wasm32-wasip2

On Windows, you can use Chocolatey to install rustup, and then use rustup to install the Windows toolchain:

shell

choco install rustup.install

shell

rustup toolchain install stable-msvc

Note: On Windows, you will also need Visual Studio's C++ tools.

Once you've installed Rust, use rustup to add the wasm32-wasip2 target:

shell

rustup target add wasm32-wasip2

TypeScript

Install the TypeScript toolchain

Requirements:

• npm v10.8+
• TypeScript v5.6+

On macOS or Linux, you can use Homebrew to install npm (and Node.js):

shell

brew install node

On Windows, you can use Chocolatey to install npm (and Node.js):

shell

choco install nodejs

Once you've installed Node.js and npm on macOS, Linux, or Windows, you can use npm to install TypeScript:

shell

npm install -g typescript

My Language Isn't Listed

If you prefer working in a language that isn't listed here, let us know!

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Create a new component

Now that we've installed wash and our language toolchain, it's time to create a new component project.

Go

In your terminal, run:

shell

wash new component hello --template-name hello-world-tinygo

After a moment, wash will create a new directory called hello with all of the required project files for building a component from your chosen language.

Navigate to the hello project directory:

sh

cd hello

Rust

In your terminal, run:

shell

wash new component hello --template-name hello-world-rust

After a moment, wash will create a new directory called hello with all of the required project files for building a component from your chosen language.

Navigate to the hello project directory:

sh

cd hello

TypeScript

In your terminal, run:

shell

wash new component hello --template-name hello-world-typescript

After a moment, wash will create a new directory called hello with all of the required project files for building a component from your chosen language.

Navigate to the hello project directory:

sh

cd hello

Install the npm packages for your project:

shell

npm install

Start your developer loop

From our project directory, we'll run:

shell

wash dev

The wash dev command automatically builds your WebAssembly component and deploys it to a local wasmCloud environment. This will take a moment, and the terminal output will update you on the process. The last step should look like this:

text

✅ Successfully started host, logs writing to /home/.wash/dev/kSKCGi/wasmcloud.log
🚧 Building project...
...
✨ HTTP Server: Access your application at http://127.0.0.1:8000
👀 Watching for file changes (press Ctrl+c to stop)...

By default, the application will run on our local port 8000. In a new terminal tab, we can curl our application:

shell

curl localhost:8000

The application should return:

text

Hello from <language>!

You just ran a WebAssembly application in wasmCloud!

Make the application yours

Now we'll make a change to our code and see how the running application updates automatically.

Go

Modify main.go

The Go code for our component is found in hello/main.go.

Open the file in your code editor and change the "Hello" message in the handleRequest function. You might modify the message to say hello from WebAssembly, your own name, or whatever else you like.

go

// Send HTTP response
func handleRequest(w http.ResponseWriter, r *http.Request) {
  fmt.Fprintf(w, "Hello from Go!\n") 
  fmt.Fprintf(w, "Hello from Wasm!\n") 
}

Rust

Modify lib.rs

The Rust code for our component is found in hello/src/lib.rs.

Open the file in your code editor and change the "Hello" message on line 19. You might modify the message to say hello from WebAssembly, your own name, or whatever else you like.

rust

response_body
            .write()
            .unwrap()
            .blocking_write_and_flush(b"Hello from Rust!\n") 
            .blocking_write_and_flush(b"Hello from Wasm!\n") 
            .unwrap();

TypeScript

Modify http-hello-world.ts

The TypeScript code for our component is found in hello/http-hello-world.ts.

Open the file in your code editor and change the "Hello" message on line 23. You might modify the message to say hello from WebAssembly, your own name, or whatever else you like.

typescript

// Write hello world to the response stream
outputStream.blockingWriteAndFlush(
  new Uint8Array(new TextEncoder().encode('Hello from Typescript!\n')) 
  new Uint8Array(new TextEncoder().encode('Hello from Wasm!\n')) 
);

My Language Isn't Listed

If you prefer working in a language that isn't listed here, let us know!

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Save the modified file. The wash dev automatically builds and deploys the updated component.

In the terminal, curl the application again:

shell

curl localhost:8000

text

Hello from Wasm!

Next steps

We installed wash, built our first component, and ran our application locally with wash dev.

In our next tutorial, we'll add pluggable, reusable capabilities like key-value storage to our application.