Core Concepts

Understanding these concepts will help you navigate the Matrix ecosystem like a power user.

The Matrix Network

Matrix is a federated network of homeservers. Think of it like email:

• Your email address is tied to a provider (Gmail, Outlook, etc.)
• But you can email anyone on any provider
• Matrix works the same way for messaging

Matrix IDs

Your Matrix ID (MXID) uniquely identifies you across the network:

@username:homeserver.org
│    │          │
│    │          └── The server where your account lives
│    └── Your chosen username
└── @ symbol indicates this is a user

Other ID types:

• !roomid:server.org - Room ID (internal identifier)
• #alias:server.org - Room alias (human-readable)
• +community:server.org - Legacy community (deprecated)

Rooms

Rooms are the core unit of communication in Matrix.

Room Properties

Property	Description
Room ID	Unique identifier like !abcd1234:server.org
Aliases	Human-readable names like #matrix:matrix.org
State	Room settings (name, topic, permissions, etc.)
Timeline	The ordered list of events (messages)

Room Types

• Direct Messages (DMs) - 1:1 conversations
• Private Rooms - Invite-only group chats
• Public Rooms - Anyone can join, often listed in room directories
• Spaces - Hierarchical organization of rooms (like Discord servers)

Events

Everything in Matrix is an event. Events are JSON objects that represent actions:

{
  "type": "m.room.message",
  "sender": "@alice:matrix.org",
  "content": {
    "msgtype": "m.text",
    "body": "Hello, Matrix!"
  },
  "origin_server_ts": 1234567890123,
  "event_id": "$eventid:matrix.org"
}

Event Types

Type	Description
m.room.message	Text, images, files, etc.
m.room.member	Join, leave, invite, ban
m.room.name	Room name changes
m.room.topic	Room topic changes
m.room.power_levels	Permission changes
m.room.encryption	E2EE settings

Federation

Federation is how homeservers communicate:

1. Alice on matrix.org sends a message to a room
2. The room has members from example.com
3. matrix.org sends the event to example.com
4. Bob on example.com receives the message

Power User Insight

When you join a room, your homeserver creates a local copy of the room state. This means:

• Messages are stored on all participating homeservers
• If one server goes down, the room continues to work
• Leaving a room removes your homeserver's copy (eventually)

End-to-End Encryption (E2EE)

Matrix supports optional E2EE using:

• Olm - For 1:1 device encryption
• Megolm - For efficient group encryption

How It Works

1. Each device has a unique device key
2. Messages are encrypted for each recipient device
3. Keys are verified via cross-signing
4. Key backup protects against device loss

Verification

Users can verify each other to ensure they're talking to the right person:

1. Emoji verification - Compare emojis on both devices
2. QR code scan - Scan a code on the other device
3. Cross-signing - Your verified devices vouch for each other

Power Levels

Rooms have a permission system based on "power levels" (0-100 by default):

Level	Typical Role	Capabilities
0	Default	Send messages
50	Moderator	Kick users, delete messages
100	Admin	Full control, change room settings

info

Power levels are completely customizable. A room can use any numbers and define custom thresholds for each action.

Spaces

Spaces are Matrix's answer to Discord servers or Slack workspaces:

• Hierarchical - Spaces can contain rooms and other spaces
• Flexible - A room can belong to multiple spaces
• Access Control - Inherit membership from parent spaces

Space: "My Community"
├── #general
├── #random
├── Space: "Development"
│   ├── #frontend
│   └── #backend
└── Space: "Social"
    ├── #gaming
    └── #music

Next Steps

• Quick Start - Get your first Matrix account
• Clients - Choose your Matrix client
• Specification - Deep dive into the protocol

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Next: Quick Start →