The Fediverse is a decentralized social network made up of thousands of independent servers (Mastodon, Pleroma, Misskey, etc.) that communicate with each other via the ActivityPub protocol. You can follow and interact with users on any compatible server, just like you can send emails from Gmail to Outlook.

Holos is a unique Fediverse client where your phone is your own ActivityPub server. Unlike traditional apps that connect to a remote server (like Mastodon), Holos stores your data, cryptographic keys, and followers directly on your device. However, your identity remains tied to the relay's domain (@you@holos.social), unless you configure your own domain via a CNAME record.

The relay solves a fundamental problem: phones don't have stable internet addresses. The relay provides a permanent identity (@you@holos.social) and forwards requests to your phone when it's online. It also caches your profile and public posts so they remain accessible even when you're offline.

When you're offline, the relay temporarily stores activities meant for you. Each activity type has a different default retention time (TTL):

• Follow requests: 365 days
• Direct messages: 30 days
• Mentions: 14 days
• Posts and others: 7 days

You can reduce these durations in the app settings (between 0 and the server maximum). As soon as you come back online, activities are synced then immediately deleted from the relay to protect your privacy.

Simply search for their full identifier (e.g., @user@mastodon.social) in the search screen. Holos will resolve the address and you can follow them like any other user. The Fediverse allows communication between all ActivityPub-compatible instances.

No. Traditional Mastodon clients connect to a remote server via an API. With Holos, your phone is the ActivityPub server itself: it doesn't use an intermediary API but communicates directly with other Fediverse servers. For example, when you visit a profile, your phone fetches the information directly from the source.

The interface offers multiple views based on your preference:

• Classic view: all content (Mastodon style)
• Images view: photos only (Instagram style)
• Videos view: videos only

Holos is more permissive than most Fediverse instances:

• Text: No character limit (Mastodon limits to 500)
• Media: No strict limit (a warning appears beyond 4 for compatibility)
• Polls: No option limit (warning beyond 4)
• Polls with media: Supported (not supported on Mastodon)
• File size: No strict limit. Media under 10 MB are cached by the relay. Larger files are served directly from your device.

Compatibility warnings inform you that some content may not display correctly on other instances, but you can ignore them.

The relay stores activities meant for you with a limited time to live (TTL). Once an activity is retrieved and processed by your device, it's deleted from the relay. If you had two devices connected to the same account, the first to sync would receive the activity and the second would never see it. There's currently no synchronization mechanism between devices.

ActivityPub works by distribution (push), not by fetching (pull). When you post, your phone sends the post directly to each follower's inbox listed locally.

Possible causes if a follower is missing:

• You reinstalled the app without restoring your data
• The "Follow" activity was lost or improperly processed

Solution: Ask the person to unfollow and re-follow you.

Go to https://codeberg.org/tom79/Holos-App/issues. First check if the issue has already been reported. If not, create a ticket with a clear title, steps to reproduce the bug, expected vs observed behavior, and your device information (model, Android/iOS version).

Translations are managed via Weblate: https://weblate.holos.social/projects/holos-app/. Create a free account and submit translations in your language. Do not edit translation files directly in the code, Weblate changes are automatically synced with the repository.

Yes. Your private keys and data never leave your device. The relay only stores your public profile and public posts to make them accessible offline. All communications are encrypted (HTTPS) and cryptographically signed. Nobody, not even us, can post on your behalf.

Holos offers three types of backup:

• Cloud backup (highly recommended): Configure S3-compatible storage as soon as you create your account. Schedule automatic daily, weekly, or monthly backups. This backup contains your entire database. WebDAV/Nextcloud support coming soon.
• Local backup: Manually export your database as a ZIP to your device.
• Critical backup (automatic): A small emergency file is automatically created every 20 minutes to recover your data in case of database corruption.

If you've configured a cloud backup, you can restore your entire account on a new device. That's why it's strongly recommended to configure this backup as soon as you create your account. Without any backup, you'll need to create a new account.

Yes. Holos supports the ActivityPub migration protocol (Move). You can import your subscriptions from another instance, and if you leave Holos, you can redirect your followers to your new account.

Migration between relays with your own domain: If you use your own domain via CNAME, you can change relays without performing an ActivityPub migration. Simply register your account on another relay and redirect your CNAME to that new relay. This option requires technical skills (DNS management).