HTTP2.0 on localhost with Caddy

HTTP2.0 is the single greatest improvement in the recent history of web performance optimization. To quickly test its benefits on your local machine, you only need an easy-to-setup HTTP2.0 supporting webserver like Caddy and a self-signed certificate.

Caddy is an easy-to-install, open-souce HTTP2.0 server written in Go that is well-documented. This makes it ideal for some quick HTTP2.0 testing on your localhost or alongside a running web server.

For starters, download the provided Caddy package for your OS and test that you can start in on the commandline by calling "caddy". Caddy will initiate a web server in the current working directory just like "python -m http.server" or Node's "http-server".

To make Caddy serve contents via HTTP2.0, we require a SSL certificate because encryption is part of the core spec for HTTP2.0. While Caddy has an amazing auto-magical certificate generation process using Let's Encrypt built-in, you can't easily receive a certificate for your localhost that way.

We can create our own, self-signed certificate for HTTP2.0 testing with a single command, however. Just execute:

openssl req -new -newkey rsa:2048 -sha256 -days 365 -nodes -x509 -keyout cert.key -out cert.crt

on your commandline to generate a SSL certificate + key pair.

Now all we need to do is to tell Caddy to use the self-signed certificate. Create a new file in the working directory you want to serve with HTTP2.0 and call it "Caddyfile". Caddyfiles are configuration files automatically read by Caddy if present.

Put the following lines into your Caddyfile to make Caddy serve contents via HTTP2.0 using the self-signed certificate:

tls cert.crt cert.key

You can read more about this syntax in the Caddy documentation on TLS. Now just point your browser to "https://localhost", click through the security warning that you're connecting to a server that's using only a self-signed certificate and enjoy testing your website with HTTP2.0.


As of version 0.9, Caddy can now create its own self-signed certificates for local testing. See Caddy's blog post for the v0.9 release for details.

HTTP2.0 on localhost with Caddy