How to use a different domain name for Akkoma and the users it serves¶

Akkoma users are primarily identified by a user@example.org handle, and you might want this identifier to be the same as your email or jabber account, for instance. However, in this case, you are almost certainly serving some web content on https://example.org already, and you might want to use another domain (say akkoma.example.org) for Akkoma itself.

Akkoma supports that, but it might be tricky to set up, and any error might prevent you from federating with other instances.

If you are already running Akkoma on example.org, it is no longer possible to move it to akkoma.example.org.

Account identifiers¶

It is important to understand that for federation purposes, a user in Akkoma has two unique identifiers associated:

A webfinger acct: URI, used for discovery and as a verifiable global name for the user across Akkoma instances. In our example, our account's acct: URI is acct:user@example.org
An author/actor URI, used in every other aspect of federation. This is the way in which users are identified in ActivityPub, the underlying protocol used for federation with other Akkoma instances. In our case, it is https://akkoma.example.org/users/user.

Both account identifiers are unique and required for Akkoma. An important risk if you set up your Akkoma instance incorrectly is to create two users (with different acct: URIs) with conflicting author/actor URIs.

WebFinger¶

As said earlier, each Akkoma user has an acct: URI, which is used for discovery and authentication. When you add @user@example.org, a webfinger query is performed. This is done in two steps:

Querying https://example.org/.well-known/host-meta (where the domain of the URL matches the domain part of the acct: URI) to get information on how to perform the query. This file will indeed contain a URL template of the form https://example.org/.well-known/webfinger?resource={uri} that will be used in the second step.
Fill the returned template with the acct: URI to be queried and perform the query: https://example.org/.well-known/webfinger?resource=acct:user@example.org

Configuring your Akkoma instance¶

DO NOT ATTEMPT TO CONFIGURE YOUR INSTANCE THIS WAY IF YOU DID NOT UNDERSTAND THE ABOVE

Configuring Akkoma¶

Akkoma has a two configuration settings to enable using different domains for your users and Akkoma itself. host in Pleroma.Web.Endpoint and domain in Pleroma.Web.WebFinger. When the latter is not set, it defaults to the value of host.

Be extra careful when configuring your Akkoma instance, as changing host may cause remote instances to register different accounts with the same author/actor URI, which will result in federation issues!

config :pleroma, Pleroma.Web.Endpoint,
  url: [host: "pleroma.example.org"]

config :pleroma, Pleroma.Web.WebFinger, domain: "example.org"

domain - is the domain for which your Akkoma instance has authority, it's the domain used in acct: URI. In our example, domain would be set to example.org.
host - is the domain used for any URL generated for your instance, including the author/actor URL's. In our case, that would be akkoma.example.org.

Configuring WebFinger domain¶

Now, you have Akkoma running at https://akkoma.example.org as well as a website at https://example.org. If you recall how webfinger queries work, the first step is to query https://example.org/.well-known/host-meta, which will contain an URL template.

Therefore, the easiest way to configure example.org is to redirect /.well-known/host-meta to akkoma.example.org.

With nginx, it would be as simple as adding:

location = /.well-known/host-meta {
       return 301 https://akkoma.example.org$request_uri;
}

in example.org's server block.