Overview

It's possible to extend Hubzilla's functionality with app. Some apps are available by default, others need to be installed by the instance's admin.

Here's a selection of the default apps:

• Articles
  Blog functionality for your channel
• Calendar
  And event Calendar with CalDav support
• CardDav
  Address book management
• Chatrooms
  Self-explanatory
• Files
  Your cloud file storage with access control. Also accessible through WebDAV.
• Guest Access
  Create guest tokens for people who are not on Hubzilla to share content with them, including files and photos
• Photos
  Again, self-explanatory
• Privacy groups
  Lets you organize your connections in groups for easier access control.
• Webpages
  A tool to create static pages for your channel
• Wiki
  Lets you create wikis such as this one.
  

And a selection of additional apps (descriptions mostly from the admin interface):

• Adult Photo Flag
  Provides an optional feature to hide individual photos from the default album view
• b2tbtn
  Show link to go back to the top of the page.
• Bookmarker
  Replace #^ with a bookmark icon
• cart
  Core cart utilities for orders and payments
• Channel reputation
  Reputation system for community channels (forums, etc.)
• Chess
  Hubzilla plugin for decentralized, identity-aware chess games powered by chessboard.js
• Chord generator
  Guitar Chord Generator Application
• Diaspora Protocol
  Connect to the Diaspora decentralized social network
• Emojione
  Emoji emoticons
• Flattr Widget
  Add a Flattr Button to the left/right aside are to allow the flattring of one thing (e.g. the for a blog)
• Fuzzy location
  If you have browser location enabled for your posts, provide a bit of fuzziness to your actual location.
• Gallery
  Album gallery and photo viewer based on photoswipe
• GNU social Connector
  Relay public postings to a connected GNU social account (formerly StatusNet)
• GNU-Social Protocol
  Connect to GNU-Social accounts (formerly StatusNet)
• Hilite
  Syntax highlight code blocks
• IRC Chat Plugin
  add an Internet Relay Chat chatroom
• NSFW
  Collapse posts with inappropriate content
• OpenStreetMap
  Use OpenStreetMap for displaying locations. After activation the post location just beneath your avatar in your posts will link to OpenStreetMap. Let's you embed maps in your posts.
• PubCrawl
  An unapologetically non-compliant ActivityPub Protocol implemention
• PubSubHubBub
  Required for GNU-Social protocol. Add PuSH capability to channel feeds
• Qrator
  QR generator
• superblock
  block channels
• TOTP
  two-factor authentication
  

Checking for available apps

Before you choose your hub where to sign up, you might want to check which apps are installed. You can do so by calling up the base url for the hub and append siteinfo.json. For this hub, the link looks like this:
https://hubzilla.lazyteddy.eu/siteinfo.json
The installed apps are listed under "Plugins".

Installing apps

In order to install new apps, click the hamburger menu in the top right corner of the screen and choose "Add apps". From there, click on "Available apps" on the left. This takes you here:
/apps/available

Recommended apps

NSFW

This app lets you specify keywords and then collapses posts in the stream if those keywords are found. If your contacts tag their NSFW posts correctly, you shouldn't see any nude pictures in your stream. I also know somebody who was getting too many pictures of spiders in her stream, so she added "spider" to the list of keywords.

Superblock

An absolute must-have, as far as I'm concerned. Does what it says - it lets you block users from communicating with you in any way, shape, or form. Also hides their comments on your connections' posts in your stream.

Privacy Groups

Organize your connections in groups. Makes it easy to share items (posts, photos, files etc.) with a selected group of people, without having to choose them individually each time.

Federation apps

If you want to connect to people elsewhere in the Federation / the Fediverse, you have to install the necessary protocols:

• Diaspora (Diaspora / Friendica)
• ActivityPub (e.g. Mastodon / Pleroma / Friendica)
• GNU-Social
  

Friendica is kind of an odd case, as it supports more than one protocol.