Hubzilla Documentation: About


What is Hubzilla?

Hubzilla is a free and open source set of web applications and services running on a special kind of web server, called a "hub", that can connect to other hubs in a decentralised network we like to call "the grid", providing sophisticated communications, identity, and access control services which work together seamlessly across domains and independent websites. It allows anybody to publicly or privately publish content via "channels", which are the fundamental, cryptographically secured identities that provide authentication independently of the hubs which host them. This revolutionary liberation of online identity from individual servers and domains is called "nomadic identity", and it is powered by the Zot protocol, a new framework for decentralised access control with fine-grained, extensible permissions.

Right... so what is Hubzilla?

From the practical perspective of hub members who use the software, Hubzilla offers a variety of familiar, integrated web apps and services, including:
  • social networking discussion threads
  • cloud file storage
  • calendar and contacts (with CalDAV and CardDAV support)
  • webpage hosting with a content management system
  • wiki
  • and more...

While all of these apps and services can be found in other software packages, only Hubzilla allows you to set permissions for groups and individuals who may not even have accounts on your hub! In typical web apps, if you want to share things privately on the internet, the people you share with must have accounts on the server hosting your data; otherwise, there is no robust way for your server to authenticate visitors to the site to know whether to grant them access. Hubzilla solves this problem with an advanced system of remote authentication that validates the identity of visitors by employing techniques that include public key cryptography.

Software Stack

The Hubzilla software stack is a relatively standard webserver application written primarily in PHP/MySQL and requiring little more than a web server, a MySQL-compatible database, and the PHP scripting language. It is designed to be easily installable by those with basic website administration skills on typical shared hosting platforms with a broad range of computing hardware. It is also easily extended via plugins and themes and other third-party tools.


An instance of this software running on a standard web server

The global network of hubs that exchange information with each other using the Zot protocol.

The fundamental identity on the grid. A channel can represent a person, a blog, or a forum to name a few. Channels can make connections with other channels to share information with highly detailed permissions.

Channels can have clones associated with separate and otherwise unrelated accounts on independent hubs. Communications shared with a channel are synchronized among the channel clones, allowing a channel to send and receive messages and access shared content from multiple hubs. This provides resilience against network and hardware failures, which can be a significant problem for self-hosted or limited-resource web servers. Cloning allows you to completely move a channel from one hub to another, taking your data and connections with you. See nomadic identity.

nomadic identity
The ability to authenticate and easily migrate an identity across independent hubs and web domains. Nomadic identity provides true ownership of an online identity, because the identities of the channels controlled by an account on a hub are not tied to the hub itself. A hub is more like a "host" for channels. With Hubzilla, you don't have an "account" on a server like you do on typical websites; you own an identity that you can take with you across the grid by using clones.

The novel JSON-based protocol for implementing secure decentralised communications and services. It differs from many other communication protocols by building communications on top of a decentralised identity and authentication framework. The authentication component is similar to OpenID conceptually but is insulated from DNS-based identities. Where possible remote authentication is silent and invisible. This provides a mechanism for internet-scale distributed access control which is unobtrusive.


This page lists some of the core features of Hubzilla that are bundled with the official release. Hubzilla is a highly extensible platform, so more features and capabilities can be added via additional themes and plugins.

Affinity Slider

When adding connnections in Hubzilla, members have the option of assigning "affinity" levels (how close your friendship is) to the new connection.  For example, when adding someone who happens to be a person whose blog you follow, you could assign their channel an affinity level of "Acquaintances".

On the other hand, when adding a friend's channel, they could be placed under the affinity level of "Friends".

At this point, Hubzilla Affinity Slider tool, which usually appears at the top of your "Matrix" page, adjusts the content on the page to include those within the desired affinity range. Channels outside that range will not be displayed, unless you adjust the slider to include them.

The Affinity Slider allows instantaneous filtering of large amounts of content, grouped by levels of closeness.

Connection Filtering

You have the ability to control precisely what appears in your stream using the optional "Connection Filter". When enabled, the Connection Editor provides inputs for selecting criteria which needs to be matched in order to include or exclude a specific post from a specific channel. Once a post has been allowed, all comments to that post are allowed regardless of whether they match the selection criteria. You may select words that if present block the post or ensure it is included in your stream. Regular expressions may be used for even finer control, as well as hashtags or even the detected language of the post.  

Access Control Lists

When sharing content, members have the option of restricting who sees the content.  By clicking on the padlock underneath the sharing box, one may choose desired recipients of the post, by clicking on their names.

Once sent, the message will be viewable only by the sender and the selected recipients.  In other words, the message will not appear on any public walls.

Access Control Lists may be applied to content and posts, photos, events, webpages, chatrooms and files.

Single Sign-on

Access Control Lists work for all channels in the grid due to our unique single sign-on technology. Most internal links provide an identity token which can be verified on other Hubzilla sites and used to control access to private resources. You login once to your home hub. After that, authentication to all Hubzilla resources is "magic".

WebDAV enabled File Storage

Files may be uploaded to your personal storage area using your operating system utilities (drag and drop in most cases). You may protect these files with Access Control Lists to any combination of Hubzilla members (including some third party network members) or make them public.

Photo Albums

Store photos in albums. All your photos may be protected by Access Control Lists.

Events Calendar

Create and manage events and tasks, which may also be protected with Access Control Lists. Events can be imported/exported to other software using the industry standard vcalendar/iCal format and shared in posts with others. Birthday events are automatically added from your friends and converted to your correct timezone so that you will know precisely when the birthday occurs - no matter where you are located in the world in relation to the birthday person. Events are normally created with attendance counters so your friends and connections can RSVP instantly.


You may create any number of personal chatrooms and allow access via Access Control Lists. These are typically more secure than XMPP, IRC, and other Instant Messaging transports, though we also allow using these other services via plugins.      

Webpage Building

Hubzilla has many "Content Management" creation tools for building webpages, including layout editing, menus, blocks, widgets, and page/content regions. All of these may be access controlled so that the resulting pages are private to their intended audience.


Apps may be built and distributed by members. These are different from traditional "vendor lockin" apps because they are controlled completely by the author - who can provide access control on the destination app pages and charge accordingly for this access. Most apps in Hubzilla are free and can be created easily by those with no programming skills.


Page layout is based on a description language called Comanche. Hubzilla is itself written in Comanche layouts which you can change. This allows a level of customisation you won't typically find in so-called "multi-user environments".


Share and save/manage bookmarks from links provided in conversations.    

Private Message Encryption and Privacy Concerns

Private mail is stored in an obscured format. While this is not bullet-proof it typically prevents casual snooping by the site administrator or ISP.  

Each Hubzilla channel has it's own unique set of private and associated public RSA 4096-bit keys, generated when the channels is first created. This is used to protect private messages and posts in transit.

Additionally, messages may be created utilising "end-to-end encryption" which cannot be read by Hubzilla operators or ISPs or anybody who does not know the passcode.

Public messages are generally not encrypted in transit or in storage.  

Private messages may be retracted (unsent) although there is no guarantee the recipient hasn't read it yet.

Posts and messages may be created with an expiration date, at which time they will be deleted/removed on the recipient's site.  

Service Federation

In addition to addon "cross-post connectors" to a variety of alternate networks, there is native support for importation of content from RSS/Atom feeds and using this to create special channels. Plugins are also available to communicate with others using the Diaspora and GNU-Social (OStatus) protocols. These networks do not support nomadic identity or cross-domain access control; however basic communications are supported to/from Diaspora, Friendica, GNU-Social, Mastodon and other providers which use these protocols.  

There is also experimental support for OpenID authentication which may be used in Access Control Lists. This is a work in progress. Your Hubzilla hub may be used as an OpenID provider to authenticate you to external services which use this technology.

Channels may have permissions to become "derivative channels" where two or more existing channels combine to create a new topical channel.

Privacy Groups

Our implementation of privacy groups is similar to Google "Circles" and Diaspora "Aspects". This allows you to filter your incoming stream by selected groups, and automatically set the outbound Access Control List to only those in that privacy group when you post. You may over-ride this at any time (prior to sending the post).  

Directory Services

We provide easy access to a directory of members and provide decentralised tools capable of providing friend "suggestions". The directories are normal Hubzilla sites which have chosen to accept the directory server role. This requires more resources than most typical sites so is not the default. Directories are synchronised and mirrored so that they all contain up-to-date information on the entire network (subject to normal propagation delays).  


For Hubzilla hubs that use TLS/SSL, client to server communications are encrypted via TLS/SSL.  Given recent disclosures in the media regarding widespread, global surveillance and encryption circumvention by the NSA and GCHQ, it is reasonable to assume that HTTPS-protected communications may be compromised in various ways. Private communications are consequently encrypted at a higher level before sending offsite.

Channel Settings

When a channel is created, a role is chosen which applies a number of pre-configured security and privacy settings. These are chosen for best practives to maintain privacy at the requested levels.  

If you choose a "custom" privacy role, each channel allows fine-grained permissions to be set for various aspects of communication.  For example, under the "Security and Privacy Settings" heading, each aspect on the left side of the page, has six (6) possible viewing/access options, that can be selected by clicking on the dropdown menu. There are also a number of other privacy settings you may edit.  

The options are:

- Nobody except yourself.
- Only those you specifically allow.
- Anybody in your address book.
- Anybody on this website.
- Anybody in this network.
- Anybody authenticated.
- Anybody on the Internet.

Public and Private Forums

Forums are typically channels which may be open to participation from multiple authors. There are currently two mechanisms to post to forums: 1) "wall-to-wall" posts and 2) via forum @mention tags. Forums can be created by anybody and used for any purpose. The directory contains an option to search for public forums. Private forums can only be posted to and often only seen by members.

Account Cloning

Accounts in Hubzilla are referred to as nomadic identities, because a member's identity is not bound to the hub where the identity was originally created.  For example, when you create a Facebook or Gmail account, it is tied to those services.  They cannot function without or  

By contrast, say you've created a Hubzilla identity called  You can clone it to another Hubzilla hub by choosing the same, or a different name:

Both channels are now synchronized, which means all your contacts and preferences will be duplicated on your clone.  It doesn't matter whether you send a post from your original hub, or the new hub.  Posts will be mirrored on both accounts.

This is a rather revolutionary feature, if we consider some scenarios:

- What happens if the hub where an identity is based suddenly goes offline?  Without cloning, a member will not be able to communicate until that hub comes back online (no doubt many of you have seen and cursed the Twitter "Fail Whale").  With cloning, you just log into your cloned account, and life goes on happily ever after.

- The administrator of your hub can no longer afford to pay for his free and public Hubzilla hub. He announces that the hub will be shutting down in two weeks.  This gives you ample time to clone your identity(ies) and preserve yourHubzilla relationships, friends and content.

- What if your identity is subject to government censorship?  Your hub provider may be compelled to delete your account, along with any identities and associated data.  With cloning, Hubzilla offers censorship resistance.  You can have hundreds of clones, if you wanted to, all named different, and existing on many different hubs, strewn around the internet.  

Hubzilla offers interesting new possibilities for privacy. You can read more at the <<Private Communications Best Practices>> page.

Some caveats apply. For a full explanation of identity cloning, read the <HOW TO CLONE MY IDENTITY>.

Multiple Profiles

Any number of profiles may be created containing different information and these may be made visible to certain of your connections/friends. A "default" profile can be seen by anybody and may contain limited information, with more information available to select groups or people. This means that the profile (and site content) your beer-drinking buddies see may be different than what your co-workers see, and also completely different from what is visible to the general public.

Account Backup

Hubzilla offers a simple, one-click account backup, where you can download a complete backup of your profile(s). Backups can then be used to clone or restore a profile.

Account Deletion

Accounts can be immediately deleted by clicking on a link. That's it.  All associated content is then deleted from the grid (this includes posts and any other content produced by the deleted profile). Depending on the number of connections you have, the process of deleting remote content could take some time but it is scheduled to happen as quickly as is practical.

Deletion of content

Any content created in Hubzilla remains under the control of the member (or channel) that originally created it.  At any time, a member can delete a message, or a range of messages.  The deletion process ensures that the content is deleted, regardless of whether it was posted on a channel's primary (home) hub, or on another hub, where the channel was remotely authenticated via Zot (Hubzilla communication and authentication protocol).


Similar to any other modern blogging system, social network, or a micro-blogging service, Hubzilla supports the uploading of files, embedding of videos, linking web pages.


Posts and comments can be previewed prior to sending and edited after sending.


Posts can be turned into "consensus" items which allows readers to offer feedback, which is collated into "agree", "disagree", and "abstain" counters. This lets you gauge interest for ideas and create informal surveys.

Extending Hubzilla

Hubzilla can be extended in a number of ways, through site customisation, personal customisation, option setting, themes, and addons/plugins.


An API is available for use by third-party services. A plugin also provides a basic implementation of the Twitter API (for which hundreds of third-party tools exist). Access may be provided by login/password or OAuth, and client registration of OAuth applications is provided.