`zrok` (*/ziːɹɒk/ ZEE-rock*) is a secure, open-source, self-hostable sharing platform that simplifies shielding and sharing network services or files. There's a hardened zrok-as-a-service offering available at [zrok.io](https://zrok.io) with a generous free tier.
The best ways to engage are [Discourse](https://openziti.discourse.group/) for questions and [GitHub Issues](https://github.com/openziti/zrok/issues) for documenting problems.
[Read more about zrok open source](/concepts/opensource.md).
`zrok` is a _Ziti Native Application_, built on the [OpenZiti](https://openziti.io) platform, and supported by the OpenZiti community and NetFoundry team.
If [sharing publicly](./concepts/sharing-public.mdx), you can reserve a subdomain, enable authentication options, or both. Public shares proxy HTTPS to your service or files.
If [sharing privately](./concepts/sharing-private.mdx), only users with the share token can access your share. In addition to what you can share publicly, private shares can include TCP and UDP services.
A zrok environment usually refers to an enabled device where shares and accesses can be created, .e.g., `~/.zrok` on a Unix machine. It can be a specific user's environment or a system-wide agent's environment owned by the administrator.
When your `zrok` account was created, the service generated a _secret token_ that identifies and authenticates in a single step. Protect your secret token as if it were a password, or an important account number; it's a _secret_, protect it.
When we left off you had downloaded, extracted, and configured your `zrok` environment. In order to use that environment with your account, you'll need to `enable` it. Enabling an environment generates a secure identity and the necessary underlying security policies with the OpenZiti network hosting the `zrok` service.
From the web console, click on your email address in the upper right corner of the header. That drop down menu contains an `Enable Your Environment` link. Click that link and a modal dialog will be shown like this:
Should you want to use a non-default name for your environment, you can pass the `-d` option to the `zrok enable` command. See `zrok enable --help` for details.
The explorer supports clicking, dragging, mouse wheel zooming, and selecting the nodes in the graph for more information (and available actions) for the selected node. If you ever get lost in the explorer, click the  _zoom to fit_ icon in the lower right corner of the explorer.
With your `zrok` account you can `zrok enable` multiple environments. This will allow you to run `zrok share` in one environment, and `zrok access` in other environments.
Shared resources are _ephemeral_ by default; as soon as you terminate the `zrok share` command, the entire share is removed and is no longer available to any users. Identifiers for shared resources are randomly allocated when the share is created.
For example, I might create a public share using the `zrok share public` command, which results in my `zrok` instance exposing a URL like `https://2ptgbr8tlfvk.share.zrok.io` to access my resources.
In this case, my share was given the "share token" of `2ptgbr8tlfvk`. That URL can be given to any user, allowing them to immediately access the shared resources directly from my local environment, all without exposing any access to my private, secure environment. The physical network location of my environment is not exposed to anonymous consumers of my resources.
If we click on the environment in the explorer, we're shown all of the shares for that environment (including our new share), along with a spark line that shows the activity:
Rather than allowing access to your service through a public frontend, a _private_ share is only exposed to the underlying OpenZiti network, and can only be accessed using the `zrok access` command.
The `zrok access private wvszln4dyz9q` command can be run by any `zrok` user, allowing them to create and bind a local HTTP listener, that allows for private access to your shared resources.
Without specifying a _backend mode_, the `zrok share` command will assume that you're trying to share a `proxy` resource. A `proxy` resource is usually some private HTTP/HTTPS endpoint (like a development server, or a private application) running in your local environment. Usually such an endpoint would have no inbound connectivity except for however it is reachable from your local environment. It might be running on `localhost`, or only listening on a private LAN segment behind a firewall.
The `zrok share` command accepts a `--backend-mode` option. Besides `proxy`, the current `v0.3` release (as of this writing) also supports a `web` mode. The `web` mode allows you to specify a local folder on your filesystem, and instantly turns your `zrok` client into a web server, exposing your web content either _publicly_ or _privately_ without having to a configure a web server.
`zrok` shares are _ephemeral_ unless you specifically create a "reserved" share.
A reserved share can be re-used multiple times; it will survive termination of the `zrok share` command, allowing for longer-lasting semi-permanent access to shared resources.
You'll want to remember the share token (`mltwsinym1s2` in this case), and the frontend endpoint URL. If this were a _private_ reserved share, there would not be a frontend URL.
This is the `404` error message returned by the `zrok` frontend. We're getting this because we haven't yet started up a `zrok share` for the service. Let's do that:
With the reserved share, we're free to stop and restart the `zrok share reserved` command as many times as we want, without losing the token for our share.
In summary, `zrok` lets you easily and securely share resources with both general internet users (through _public_ sharing) and also with other `zrok` users (through _private_ sharing).
Here's a quick review of the `zrok` mental model and the vocabulary.
You create an _account_ with a `zrok` _instance_. Your account is identified by a username and a password, which you use to log into the _web console_. Your account also has a _secret token_, which you will use to authenticate from the `zrok` command-line to interact with the _instance_.
You create a new _account_ with NetFoundry's `zrok` _instance_ by subscribing in [myzrok.io](https://myzrok.io) or in a self-hosted `zrok` _instance_ by running [the `zrok invite` command](/guides/self-hosting/self-service-invite.mdx).
Using your _secret token_ you use the `zrok` command-line interface to create an _environment_. An _environment_ corresponds to a single command-line user on a specific _host system_.
You create a new _environment_ by using the `zrok enable` command.
### Shares
Once you've enabled an _environment_, you then create one or more _shares_. Shares have either a _public_ or _private_ _sharing mode_. _Shares_ share a specific type of resource using a _backend mode_. As of this writing `zrok` supports a `proxy` _backend mode_ to share local HTTP resources as a _reverse proxy_. `zrok` also supports a `web` _backend mode_ to share local file and HTML resources by enabling a basic HTTP server.
Every _share_ is identified by a _share token_. _Public shares_ can be accessed through either a _frontend_ instance offered through the `zrok` _instance_, or through the `zrok access` command. _Private shares_ can only be accessed through the `zrok access` command.
You use the `zrok share` command to create and enable _ephemeral shares_.
### Reserved Shares
`zrok` supports creating _shares_ that have a consistent _share token_ that survives restarts of the `zrok share` command. These are considered _non-ephemeral_, and is callled a _reserved share_.
You use the `zrok reserve` command to create _reserved shares_. Reserved shares last until you use the `zrok release` command to delete them.
