Let's get started

Download the spin binary using the install.sh script hosted on this site:

$ curl -fsSL https://wasm-functions.fermyon.app/downloads/install.sh | bash

Then move the spin binary somewhere in your path, so you can run it from anywhere. For example:

$ sudo mv ./spin /usr/local/bin/spin

Download the spin binary using the install.sh script hosted on this site:

$ curl -fsSL https://wasm-functions.fermyon.app/downloads/install.sh | bash

Then move the spin binary somewhere in your path, so you can run it from anywhere. For example:

$ sudo mv ./spin /usr/local/bin/spin

Download the Windows binary release of Spin from GitHub.

Unzip the binary release and place the spin.exe in your system path.

To build Spin apps with JavaScript, Node.js must be installed on your system. Head over to https://nodejs.org/en/download, to download Node.js.

Once Node.js is installed on your machine, you can check its version using the following command:

node --version
v22.13.0

We recommend Node.js version 22 (or newer).

To build Spin apps with TypeScript, Node.js must be installed on your system. Head over to https://nodejs.org/en/download, to download Node.js.

Once Node.js is installed on your machine, you can check its version using the following command:

node --version
v22.13.0

We recommend Node.js version 22 (or newer).

To build Spin apps with Rust, Rust tooling must be installed on your machine. Head over to https://www.rust-lang.org/tools/install, to find detailed installation instructions for your operating system.

Once Rust tooling is installed, you’ll need the wasm32-wasip1 target for Rust.

$ rustup target add wasm32-wasip1

You’ll need the TinyGo compiler, as the standard Go compiler does not yet support WASI exports. See the TinyGo installation guide.

$ spin new -t http-js --accept-defaults hello-spin

The http-js template creates the application boilerplate for you. Once it has finished change to the application directory (hello-spin):

$ cd hello-spin

From within the application directory install the necessary dependencies using your package manager of choice (we will use npm here):

$ npm install

The http-js template generates an idiomatic JavaScript application. Take a few seconds and explore the source code generated by the template in src/index.js:

// For AutoRouter documentation refer to https://itty.dev/itty-router/routers/autorouter
import { AutoRouter } from 'itty-router';

let router = AutoRouter();

// Route ordering matters, the first route that matches will be used
// Any route that does not return will be treated as a middleware
// Any unmatched route will return a 404
router
    .get("/", () => new Response("hello universe"))
    .get('/hello/:name', ({ name }) => `Hello, ${name}!`)

addEventListener('fetch', async (event) => {
    event.respondWith(router.fetch(event.request));
});

$ spin new -t http-ts --accept-defaults hello-spin

The http-ts template creates the application boilerplate for you. Once it has finished change to the application directory (hello-spin):

$ cd hello-spin

From within the application directory install the necessary dependencies using your package manager of choice (we will use npm here):

$ npm install

The http-ts template generates an idiomatic TypeScript application. Take a few seconds and explore the source code generated by the template in src/index.ts:

// For AutoRouter documentation refer to https://itty.dev/itty-router/routers/autorouter
import { AutoRouter } from 'itty-router';

let router = AutoRouter();

// Route ordering matters, the first route that matches will be used
// Any route that does not return will be treated as a middleware
// Any unmatched route will return a 404
router
    .get("/", () => new Response("hello universe"))
    .get('/hello/:name', ({ name }) => `Hello, ${name}!`)

//@ts-ignore
addEventListener('fetch', async (event: FetchEvent) => {
    event.respondWith(router.fetch(event.request));
});

$ spin new -t http-rust --accept-defaults hello-spin

The http-rust template creates the application boilerplate for you. Once it has finished change to the application directory (hello-spin):

$ cd hello-spin

The http-rust template generates an idiomatic Rust application. Take a few seconds and explore the source code generated by the template in src/lib.rs:

use spin_sdk::http::{IntoResponse, Request, Response};
use spin_sdk::http_component;

/// A simple Spin HTTP component.
#[http_component]
fn handle_hello_spin(req: Request) -> anyhow::Result<impl IntoResponse> {
    println!("Handling request to {:?}", req.header("spin-full-url"));
    Ok(Response::builder()
        .status(200)
        .header("content-type", "text/plain")
        .body("Hello, Fermyon")
        .build())
}

$ spin new -t http-go --accept-defaults hello-spin

The http-go template creates the application boilerplate for you. Once it has finished change to the application directory (hello-spin):

$ cd hello-spin

The http-go template generates an idiomatic Go(lang) application. Take a few seconds and explore the source code generated by the template in main.go:

package main

import (
	"fmt"
	"net/http"

	spinhttp "github.com/fermyon/spin/sdk/go/v2/http"
)

func init() {
	spinhttp.Handle(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "text/plain")
		fmt.Fprintln(w, "Hello Fermyon!")
	})
}

func main() {}

$ spin build

Building component hello-spin with `npm run build`

> hello-spin@1.0.0 build
> npx webpack --mode=production && npx mkdirp target && npx j2w -i dist.js -d combined-wit -n combined -o target/hello-spin.wasm

asset dist.js 5.93 KiB [compared for emit] [javascript module] (name: main)
orphan modules 25.5 KiB [orphan] 25 modules
./src/spin.js + 2 modules 5.95 KiB [built] [code generated]
webpack 5.97.1 compiled successfully in 66 ms
Using user provided wit in: combined-wit
Successfully written component
Finished building all Spin components

$ spin build

Building component hello-spin with `npm run build`

> hello-spin@1.0.0 build
> npx webpack --mode=production && npx mkdirp target && npx j2w -i dist.js -d combined-wit -n combined -o target/hello-spin.wasm

asset dist.js 6 KiB [emitted] [javascript module] (name: main)
orphan modules 25.4 KiB [orphan] 25 modules
./src/spin.ts + 2 modules 5.97 KiB [built] [code generated]
webpack 5.97.1 compiled successfully in 509 ms
Using user provided wit in: combined-wit
Successfully written component
Finished building all Spin components

$ spin build

Building component hello-spin with `cargo build --target wasm32-wasip1 --release`
    Updating crates.io index
     Locking 95 packages to latest compatible versions
     ...
     Compiling hello-spin v0.1.0 (/Users/john/hello-spin)
    Finished `release` profile [optimized] target(s) in 9.89s
Finished building all Spin components

$ spin build
Executing the build command for component hello-spin: tinygo build -target=wasi -gc=leaking -no-debug -o main.wasm main.go
go: downloading github.com/fermyon/spin/sdk/go v0.10.0
Finished building all Spin components

If the build fails, check:

• Are you in the hello-spin directory?
• Did you successfully install TinyGo?
• Are your versions of Go and TinyGo up to date? The Spin SDK needs TinyGo 0.27 or above.
• Set Environment Variable CGO_ENABLED=1. (Since the Go SDK is built using CGO, it requires the CGO_ENABLED=1 environment variable to be set.)

If you would like to know what build command Spin runs for a component, you can find it in the manifest, in the component.(id).build section:

[component.hello-spin.build]
command = "tinygo build -target=wasi -gc=leaking -no-debug -o main.wasm main.go"

You can always run this command manually; spin build is a shortcut to save you having to remember it.