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WAGI: WebAssembly Gateway Interface

WAGI is the easiest way to get started writing WebAssembly microservices and web apps.

WARNING: This is experimental code. It is not considered production-grade by its developers, neither is it "supported" software.

DeisLabs is experimenting with many WASM technologies right now. This is one of a multitude of projects (including Krustlet) designed to test the limits of WebAssembly as a cloud-based runtime.


WAGI allows you to run WebAssembly WASI binaries as HTTP handlers. Write a "command line" application that prints a few headers, and compile it to WASM32-WASI. Add an entry to the modules.toml matching URL to WASM module. That's it.

You can use any programming language that can compile to WASM32-WASI.


Here's the fastest way to try out WAGI. For details, checkout out the documentation.

  1. Get the latest binary release
  2. Unpack it tar -zxf wagi-VERSION-OS.tar.gz
  3. Run the wagi --help command

If you would like to try out a few simple configurations, we recommend cloning this repository and then using the examples directory:

$ wagi -c examples/modules.toml
No log_dir specified, using temporary directory /var/folders/hk/l1mlxz1x01x9yl33ll9vh9980000gp/T/.tmpx55XkJ for logs

This will start WAGI on http://localhost:3000. Use a browser or a tool like curl to test:

$ curl -v http://localhost:3000/hello/world
*   Trying
* Connected to localhost ( port 3000 (#0)
> GET /hello/world HTTP/1.1
> Host: localhost:3000
> User-Agent: curl/7.64.1
> Accept: */*
< HTTP/1.1 200 OK
< content-type: text/html; charset=UTF-8
< content-length: 12
< date: Wed, 14 Oct 2020 22:00:59 GMT
hello world
* Connection #0 to host localhost left intact
* Closing connection 0

To add your own modules, compile your code to wasm32-wasi format and add them to the modules.toml file. Check out our Yo-Wasm project for a quick way to build Wasm modules in a variety of languages.

Examples and Demos

Wagi is an implementation of CGI for WebAssembly. That means that writing a Wagi module is as easy as sending properly formatted content to standard output. If you want to understand the details, read the Common Gateway Interface 1.1 specification.

Take a look at the Wagi Examples Repository for examples in various languages.

For a "production grade" (whatever that means for a pre-release project) module, checkout out the Wagi Fileserver: A fileserver written in Grain, compiled to Wasm, and ready to run in Wagi.


Want to chat? We hang out in the #krustlet channel of the Kubernetes Slack.

WAGI is experimental, and we welcome contributions to improve the project. In fact, we're delighted that you're even reading this section of the docs!

For bug fixes:

  • Please, pretty please, file issues for anything you find. This is a new project, and we are SURE there are some bugs to work out.
  • If you want to write some code, feel free to open PRs to fix issues. You may want to drop a comment on the issue to let us know you're working on it (so we don't duplicate effort).

For refactors and tests:

  • We welcome any changes to improve performance, clean up code, add tests, etc.
  • For style/idiom guidelines, we follow the same conventions as Krustlet

For features:

  • If there is already an issue for that feature, please let us know in the comments if you plan on working on it.
  • If you have a new idea, file an issue describing it, and we will happily discuss it.

Since this is an experimental repository, we might be a little slow to answer.

Code of Conduct

This project has adopted the Microsoft Open Source Code of Conduct.

For more information see the Code of Conduct FAQ or contact with any additional questions or comments.