Guides

Caddy

This example uses Caddy, one of the most popular web servers. Caddy can be used with Unikraft / Unikraft Cloud to serve static web content.

To run this example, follow these steps:

Install the CLI. Use the unikraft CLI or the legacy kraft CLI. You need a BuildKit builder. The easiest way to get one is via Docker. Alternatively, you can also directly set up and use BuildKit, see the quick start.

The unikraft CLI is the current standard, while kraft is the legacy version. Choose one of the CLIs below and only run the commands associated with it for the rest of this guide.

Clone the examples repository and cd into the examples/caddy2.7-go1.21/ directory:

Code
git clone https://github.com/unikraft-cloud/examples
cd examples/caddy2.7-go1.21/

Make sure to log into Unikraft Cloud and pick a metro close to you. This guide uses fra (Frankfurt, 🇩🇪):

When done, invoke the following command to deploy this app on Unikraft Cloud:

The output shows the instance address and other details:

In this case, the instance name is caddy27-go121-vhf4m and the address is https://frosty-sky-vz8kwsmb.fra.unikraft.app. They're different for each run.

Use curl to query the Unikraft Cloud instance of Caddy.

Code
curl https://frosty-sky-vz8kwsmb.fra.unikraft.app

Code
Hello World!

You can list information about the instance by running:

When done, you can remove the instance:

Customize your app

To customize the app, update the files in the repository, listed below:

Kraftfile: the Unikraft Cloud specification
rootfs/var/www/index.html: the index page of the content served
rootfs/etc/caddy/Caddyfile: the Caddy configuration file

Update the contents of the rootfs/var/www directory to serve different static web content. For example, you could change the contents of rootfs/var/www/index.html to:

Code
<!DOCTYPE html>
<html>
<head>
<title>Hello</title>
</head>
<body>
<h2>Hello, World!</h2>
</body>
</html>

After re-deploying the Caddy image on Unikraft Cloud, using curl or a browser to query it will present the new page contents.

You can generate the static web content in rootfs/var/www/ offline with tools such as Jekyll or Hugo.

If required, you can also customize the configuration of Caddy in rootfs/etc/caddy/Caddyfile. You can set a new webroot (different than rootfs), or a different internal port, or a different index page, etc.

Learn more

Use the --help option for detailed information on using Unikraft Cloud:

Or visit the CLI Reference or the legacy CLI Reference.

Edit this page

Last modified on August 11, 2026

C++ HTTP Server Debian SSH server

Guides

Caddy

This example uses Caddy, one of the most popular web servers. Caddy can be used with Unikraft / Unikraft Cloud to serve static web content.

To run this example, follow these steps:

Install the CLI. Use the unikraft CLI or the legacy kraft CLI. You need a BuildKit builder. The easiest way to get one is via Docker. Alternatively, you can also directly set up and use BuildKit, see the quick start.

The unikraft CLI is the current standard, while kraft is the legacy version. Choose one of the CLIs below and only run the commands associated with it for the rest of this guide.

Clone the examples repository and cd into the examples/caddy2.7-go1.21/ directory:

Code
git clone https://github.com/unikraft-cloud/examples
cd examples/caddy2.7-go1.21/

Make sure to log into Unikraft Cloud and pick a metro close to you. This guide uses fra (Frankfurt, 🇩🇪):

unikraft login

When done, invoke the following command to deploy this app on Unikraft Cloud:

unikraft build . --output <my-org>/caddy27-go121:latest
unikraft run --scale-to-zero policy=on,cooldown-time=1000 --metro fra -p 443:2015/http+tls -m 256M --image <my-org>/caddy27-go121:latest

The output shows the instance address and other details:

metro:        fra
name:         caddy27-go121-vhf4m
uuid:         db624eff-4739-4500-873c-f7c58e4eefd7
state:        starting
image:        <my-org>/caddy27-go121
resources:
  memory:     256MiB
  vcpus:      1
service:
  uuid:       085cfc91-34d2-0e4d-5f19-fe67832f16a8
  name:       frosty-sky-vz8kwsmb
  domains:
  - fqdn:     frosty-sky-vz8kwsmb.fra.unikraft.app
networks:
- uuid:       a72ea1ab-9686-c5b5-a8c2-fd58922f30f3
  private-ip: 10.0.6.2
  mac:        12:b0:a9:b2:fd:13
timestamps:
  created:    just now

In this case, the instance name is caddy27-go121-vhf4m and the address is https://frosty-sky-vz8kwsmb.fra.unikraft.app. They're different for each run.

Use curl to query the Unikraft Cloud instance of Caddy.

Code
curl https://frosty-sky-vz8kwsmb.fra.unikraft.app

Code
Hello World!

You can list information about the instance by running:

unikraft instances list

METRO  NAME                 STATE    IMAGE                   ARGS  MEMORY  VCPUS  FQDN                                  CREATED
fra    caddy27-go121-vhf4m  running  <my-org>/caddy27-go121        256MiB  1      frosty-sky-vz8kwsmb.fra.unikraft.app  2 minutes ago

When done, you can remove the instance:

unikraft instances delete caddy27-go121-vhf4m

Customize your app

To customize the app, update the files in the repository, listed below:

Kraftfile: the Unikraft Cloud specification
rootfs/var/www/index.html: the index page of the content served
rootfs/etc/caddy/Caddyfile: the Caddy configuration file

Update the contents of the rootfs/var/www directory to serve different static web content. For example, you could change the contents of rootfs/var/www/index.html to:

Code
<!DOCTYPE html>
<html>
<head>
<title>Hello</title>
</head>
<body>
<h2>Hello, World!</h2>
</body>
</html>

After re-deploying the Caddy image on Unikraft Cloud, using curl or a browser to query it will present the new page contents.

You can generate the static web content in rootfs/var/www/ offline with tools such as Jekyll or Hugo.

Learn more

Use the --help option for detailed information on using Unikraft Cloud:

unikraft --help

Or visit the CLI Reference or the legacy CLI Reference.

Edit this page

Last modified on August 11, 2026

C++ HTTP Server Debian SSH server