smartphone
The Concept
Unlike traditional social networks where your data lives on remote servers, Holos runs a complete ActivityPub server directly on your device. Your posts, followers, and cryptographic keys stay local, giving you control and the ability to migrate between relays.
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Your device IS your server. Your keys never leave it.
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Architecture
Mastodon, Pleroma, Misskey, Pixelfed...
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ActivityPub (HTTPS)
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Stable @handle@domain identity
cached
Profile cache (avatar, bio)
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Activity queue when offline
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Push notifications
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ActivityPub (WebSocket)
dns
Full ActivityPub server
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RSA keypair (private key stays local)
storage
SQLite database (posts, followers)
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Why a Relay Server?
Devices can't host a traditional server: IPs change, machines sleep, and there's no stable URL. The relay solves this.
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Stable URL & Message Queue
The relay provides a permanent address (@you@relay.domain) and stores activities when the app is offline.
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Smart Cache
Profiles, avatars and media are cached with adaptive TTLs: frequent refresh for active data, long duration for static media.
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IP Privacy
All outgoing traffic goes through the relay, hiding your device's IP address from remote servers.
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Receiving an Activity
When someone interacts with you (like, follow, reply), here's what happens:
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Mastodon
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Relay
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Your Device
1
A Mastodon server sends a Like activity to your inbox URL on the relay
2
The relay forwards it to your device's inbox via WebSocket in real-time
3
Your device verifies the HTTP signature and stores the activity locally
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Publishing a Post
When you create a post, here's what happens:
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Your Device
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Relay
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Followers
1
You write a post in the app, it's stored locally and signed with your RSA key
2
The signed activity is sent to the relay via WebSocket (your IP stays hidden)
3
The relay forwards it to each follower's inbox
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Offline Mode
What happens when your device is not connected?
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Incoming
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schedule
Queue
Variable TTL
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Sync
info
Activities are stored with tiered retention: follows (365d), DMs (30d), mentions (14d), posts and others (7d).
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Synchronization
When you come back online, here's what happens:
1. WS Reconnect
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2. Poll activities
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3. Send by priority
4. Confirm
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1
WebSocket automatically reconnects to the relay
2
App requests activities since last known timestamp
3
Relay sends queued activities, sorted by priority (urgent first)
4
Each processed activity is confirmed; entries expire automatically via TTL
code
App Stack
ActivityPub
WebFinger
HTTP Signatures
RSA-SHA256
WebSocket
Socket.IO
SQLite
React Native
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Holos is open source (AGPL-3.0). Audit the code, run your own relay, or contribute.