Fermyon Spin

Spin is a framework for building, deploying, and running fast, secure, and composable cloud microservices with WebAssembly.

What is Spin?

Spin is an open source framework for building and running fast, secure, and composable cloud microservices with WebAssembly. It aims to be the easiest way to get started with WebAssembly microservices, and takes advantage of the latest developments in the WebAssembly component model and Wasmtime runtime.

Spin offers a simple CLI that helps you create, distribute, and execute applications, and in the next sections we will learn more about Spin applications and how to get started.

Getting started

See the Install Spin page of the Spin documentation for a detailed guide on installing and configuring Spin, but in short run the following commands:

curl -fsSL https://developer.fermyon.com/downloads/install.sh | bash
sudo mv ./spin /usr/local/bin/spin

Alternatively, you could build Spin from source.

To get started writing apps, follow the quickstart guide, and then follow the Rust, JavaScript, Python, or Go language guides, and the guide on writing Spin applications.

Usage

Below is an example of using the spin CLI to create a new Spin application. To run the example you will need to install the wasm32-wasi target for Rust.

$ rustup target add wasm32-wasi

First, run the spin new command to create a Spin application from a template.

# Create a new Spin application named 'hello-rust' based on the Rust http template, accepting all defaults
$ spin new --accept-defaults http-rust hello-rust

Running the spin new command created a hello-rust directory with all the necessary files for your application. Change to the hello-rust directory and build the application with spin build, then run it locally with spin up:

# Compile to Wasm by executing the `build` command.
$ spin build
Executing the build command for component hello-rust: cargo build --target wasm32-wasi --release
    Finished release [optimized] target(s) in 0.03s
Successfully ran the build command for the Spin components.

# Run the application locally.
$ spin up
Logging component stdio to ".spin/logs/"

Serving http://127.0.0.1:3000
Available Routes:
  hello-rust: http://127.0.0.1:3000 (wildcard)

That's it! Now that the application is running, use your browser or cURL in another shell to try it out:

# Send a request to the application.
$ curl -i 127.0.0.1:3000
HTTP/1.1 200 OK
foo: bar
content-length: 14
date: Thu, 13 Apr 2023 17:47:24 GMT

Hello, Fermyon

You can make the app do more by editting the src/lib.rs file in the hello-rust directory using your favorite editor or IDE. To learn more about writing Spin applications see Writing Applications in the Spin documentation. To learn how to publish and distribute your application see the Publishing and Distribution guide in the Spin documentation.

For more information on the cli commands and subcommands see the CLI Reference.

Language Support for Spin Features

The table below summarizes the feature support in each of the language SDKs.

Feature	Rust SDK Supported?	TypeScript SDK Supported?	Python SDK Supported?	Tiny Go SDK Supported?	C# SDK Supported?
Triggers
HTTP	Supported	Supported	Supported	Supported	Supported
Redis	Supported	Not Supported	Not Supported	Supported	Not Supported
APIs
Outbound HTTP	Supported	Supported	Supported	Supported	Supported
Key Value Storage	Supported	Supported	Supported	Supported	Not Supported
MySQL	Supported	Not Supported	Not Supported	Not Supported	Not Supported
PostgreSQL	Supported	Not Supported	Not Supported	Not Supported	Supported
Outbound Redis	Supported	Supported	Supported	Supported	Supported
Extensibility
Authoring Custom Triggers	Supported	Not Supported	Not Supported	Not Supported	Not Supported

Contributing

We are delighted that you are interested in making Spin better! Thank you! Please follow the contributing guide. And join our Discord server.

Stay in Touch

You can join the Spin community in our Discord server where you can ask questions, get help, and show off the cool things you are doing with Spin!