Shard Detail

ktistec v1.0.0

Single user ActivityPub ( server.
activitypub crystal

Install & Use

Add the following code to your project's shard.yml under:

dependencies to use in production
- OR -
development_dependencies to use in development

  github: toddsundsted/ktistec



Ktistec is an ActivityPub ( server. It is intended for individual users, not farms of users, although support for additional users will be added in the future. It is designed to have few runtime dependencies -- for example, it uses SQLite as its database, instead of PostgreSQL + Redis + etc. It is licensed under the AGPLv3.

Ktistec powers Epiktistes, my low-volume home in the Fediverse. If you want to talk to me, I'm


Text and images

Ktistec is intended for writing and currently supports the minimum viable set of tools for that purpose.

Text formatting options include bold, italic, strikethrough, code (inline and block), superscript/subscript, headers, blockquotes with nested indentation, and both bullet and numeric lists.

Ktistec supports inline placement of images, with ActivityPub image attachments used for compatibility with non-Ktistec servers.

Drafts posts

Meaningful writing is an iterative process so Ktistec supports draft posts. Draft posts aren't visible in your timeline until you publish them.

Threaded replies

Threaded replies make it easier to follow discussions with lots of posts.

@-mention and #-hashtag autocomplete

Ktistec automatically converts @-mentions and #-hashtags into links, and to encourage hands-on-the-keyboard composition, Ktistec supports autocompletion.

Control over comment visibility

Ktistec promotes healthy dialog. Ktistec allows you to control which replies to your posts are public, and visible to anonymous users, and which are private.

Pretty URLs

Assign pretty (canonical) URLs to posts, both for SEO and as helpful mnemonics for users (and yourself).


The Fediverse is a distributed social network. You can follow other users on other servers from your timeline or by searching for them by name. Ktistec is also compatible with the "remote follow" protocol used by Mastodon and others.


Ktistec gives you control over what you see. Blocking authors and posts removes them and their content from your timeline.


Ktistec tracks metrics about how the instance is performing. Right now, the only metric is inbox and outbox volume per account, but the machinery is in place to do much more.


To run an instance of Ktistec, you'll need a server with a permanent hostname (AKA it's own domain). In the Fediverse, users are identified by (and content is addressed to) a hostname and a username.


You must build Ktistec from its source code. You will need a recent release of the Crystal programming language.

If you intend to do development, check out the main branch. In addition to Crystal, you'll also need Webpack to build the JavaScript and CSS assets from source.

If you just want to try Ktistec out, check out the dist branch.

Since the project is still in development, I don't bother with a separate build step. I just run the server:

$ LOG_LEVEL=INFO crystal run src/ktistec/


The server runs on port 3000. If you're planning on running it in production, you should put Nginx or Apache in front of it. Don't forget your SSL certificate!

When you run Ktistec for the first time, you'll need to name the server and create the primary user.

Ktistec needs to know the host name of its home on the internet. The server host name is a part of every users's identity in the Fediverse. My identity is "". The host name is "" and other federated servers, and users, know to send posts and other content to me there.

Give the server a site name, too.

After you name the server, you create the primary user. Ktistec currently supports only one user. This is intentional -- one of Ktistec's design goals is to promote a more fully distributed Fediverse.

At a minimum, you need to specify the user's username, password and timezone. You can use a single character for the username if you want, but you'll need six characters, including letters, numbers and symbols, for the password. timezone is any valid IANA time zone database string (e.g. "America/New_York").

Display name and summary are optional.

Once these steps are done, you're running!


Copyright and License

Ktistec ActivityPub Server Copyright (C) 2021 Todd Sundsted

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License along with this program. If not, see (