The document discusses the lack of a standardized signaling protocol in WebRTC, emphasizing the need for open, decentralized communication solutions like Matrix. Matrix is presented as a non-profit, open-source project that supports various messaging and VoIP applications, offering a federated architecture and JSON-based API. It aims to enable users to communicate across different applications while maintaining control over their data and privacy.

1. The missing signaling layer for WebRTC
kegan@matrix.org
http://www.matrix.org

2. WebRTC doesn’t specify a
signaling protocol.
Signaling is essential to any
interactive application.
2

3. Signaling needs to work
across varied devices.
Users are demanding more
(IM, Push notifications, call
logs, discovery)
3

4. What’s wrong with SIP?
4
• It cargo-cults the PSTN
• It’s (almost) all 1:1 communication
• Chat, file transfer etc is clunky
• No synced conversation history
• etc…

5. A new way of thinking is
required.
5

6. Wouldn’t it be nice to be able
to speak to whoever you
wanted no matter which app
they used?
6

7. 7

8. Users are locked into
proprietary communication
apps.
They have no control over
their data or their privacy.

9. I want to use the best client
for me, not be forced into
specific services chosen by
my contacts.
Email gets it right.

10. Enter Matrix
10

11. What is Matrix?
An open standard for
decentralized messaging.
11

12. Matrix is:
• Non-profit Open Source Project
• Open Standard HTTP APIs:
– Client <-> Server
– Server <-> Server
– Application Services <-> Server
• Apache-Licensed Open Source Reference Implementations
– Server (Python/Twisted)
– Client SDKs (iOS, Android, JS, Angular, Python, Perl)
– Clients (Web, iOS, Android)
– Application Services (IRC, SIP, XMPP, Lync bridges)
• A whole ecosystem of 3rd party servers, clients & services
12

13. What can it be used for?
Instant Messaging, VoIP, IoT,
“bridging” between apps
13

14. Common WebRTC signaling
(RFC 7118) is SIP over
WebSockets.
Matrix is JSON over
WebSockets/HTTP.
14

15. Matrix provides:
• Open, decentralized, eventually-consistent data store
– Instant Messages
– VoIP (call logs, duration, timestamps)
– IoT data
• Publish-subscribe (PubSub) HTTP/WS API
• “Push Gateways” to reach mobile devices (GCM/APNS)
• Server-to-Server Federation: no single point of failure.
15

16. Matrix Architecture
Clients
Home
Servers
Identity
Servers
Application
Servers

17. Functional Responsibility
• Clients: Talks simple HTTP APIs to homeservers to
push and pull messages and metadata. May be as
thin or thick a client as desired.
• Homeservers: Stores all the data for a user - the
history of the rooms in which they participate; their
public profile data.
• Application Services: Optional; delivers application
layer logic on top of Matrix (Gateways, Conferencing,
Archiving, Search etc). Can actively intercept
messages if required.
• Identity Servers: Trusted clique of servers (think DNS
root servers): maps 3rd party IDs to matrix IDs.
17

18. Matrix Concepts
@
!
{ }
Users
Message Events
Rooms
State Events
[ ]
A B
Room NameMember A
Member B
Invite C
Permissions
{ (t,s) => content }
Message
Message
Message
Message
Message
Member List

19. Matrix Concepts
@
!
{ }
Users
Message Events
Rooms
State Events
[ ]
A B
Room NameMember A
Member B
Invite C
Permissions
{ (t,s) => content }
Message
Message
Message
Message
Message
Member List
Message
Invite D

20. Matrix Concepts
@
!
{ }
Users
Message Events
Rooms
State Events
[ ]
A B
Room NameMember A
Member B
Invite C
Permissions
{ (t,s) => content }
Message
Message
Message
Message
Message
Member List
Message
Invite D

21. Matrix Concepts
@
!
{ }
Users
Message Events
Rooms
State Events
[ ]
A B
Room NameMember A
Member B
Invite C
Permissions
{ (t,s) => content }
Message
Message
Message
Message
Message
Member List
Message
Invite D D

22. Matrix Concepts
@
!
{ }
Users
Message Events
Rooms
State Events
[ ]
A B
Room NameMember A
Member B
Invite C
Permissions
{ (t,s) => content }
Message
Message
Message
Message
Message
Member List
Message
Invite D DMember D

23. Matrix Concepts
@
!
{ }
Users
Message Events
Rooms
State Events
[ ]
A B
Room NameMember A
Member B
Invite C
Permissions
{ (t,s) => content }
Message
Message
Message
Message
Message
Member List
Message
Member D D

24. Matrix Concepts
@
!
{ }
Users
Message Events
Rooms
State Events
[ ]
A B
Room NameMember A
Member B
Invite C
Permissions
{ (t,s) => content }
Message
Message
Message
Message
Message
Member List
Message
Member D D
New Room Name

25. Matrix Concepts
@
!
{ }
Users
Message Events
Rooms
State Events
[ ]
A B
New Room NameMember A
Member B
Invite C
Permissions
{ (t,s) => content }
Message
Message
Message
Message
Message
Member List
Message
Member D D

26. What things have been built
using Matrix?
26

27. Demo time!
http://matrix.org/blog/try-matrix-now
27

28. The Matrix Ecosystem
The Matrix Specification (Client/Server API)
client-sideserver-side
Other Servers and
Services
Synapse
(Reference Matrix
Server)
Matrix Application
Services
Other Clients
Matrix iOS
Console
MatrixKit (iOS)
matrix-ios-sdk
Matrix
Web
Console
matrix-
angular-
sdk
matrix-js-sdk
Android Console
matrix-android-
sdk
matrix-
react-
sdk

29. How do I use it?
The baseline protocol is JSON
over HTTP. Any device which
can make HTTP requests can
use Matrix.
29

30. The client-server API
To send a message:
curl -XPOST -d '{"msgtype":"m.text", "body":"hello"}'
"https://alice.com:8448/_matrix/client/api/v1/rooms/ROOM_ID/send/m.room.messa
ge?access_token=ACCESS_TOKEN"
{
"event_id": "YUwRidLecu"
}
30

31. The client-server API
To set up a WebRTC call:
curl -XPOST –d '{¥
"version": 0, ¥
"call_id": "12345”, ¥
"offer": {
"type" : "offer”,
"sdp" : "v=0¥r¥no=- 658458 2 IN IP4 127.0.0.1…"
}
}'
"https://alice.com:8448/_matrix/client/api/v1/rooms/ROOM_ID/send/m.call.invit
e?access_token=ACCESS_TOKEN"
{ "event_id": "ZruiCZBu” } 31

32. Basic 1:1 VoIP Matrix Signaling
Caller Callee
m.call.invite ----------->
m.call.candidate -------->
[more candidates events]
User answers call
<------ m.call.answer
[media flows]
<------ m.call.hangup
32

33. The client-server API
To persist some MIDI:
curl -XPOST –d '{¥
"note": "71",¥
"velocity": 68,¥
"state": "on",¥
"channel": 1,¥
"midi_ts": 374023441¥
}'
"https://alice.com:8448/_matrix/client/api/v1/rooms/ROOM_ID/send/org.matrix.m
idi?access_token=ACCESS_TOKEN"
{ "event_id": “ORzcZn2” }
33

34. The server-server API
curl –XPOST –H ‘Authorization: X-Matrix origin=matrix.org,key=”898be4…”,sig=“j7JXfIcPFDWl1pdJz…”’ –d ‘{
"ts": 1413414391521,
"origin": "matrix.org",
"destination": "alice.com",
"prev_ids": ["e1da392e61898be4d2009b9fecce5325"],
"pdus": [{
"age": 314,
"content": {
"body": "hello world",
"msgtype": "m.text"
},
"context": "!fkILCTRBTHhftNYgkP:matrix.org",
"depth": 26,
"hashes": {
"sha256": "MqVORjmjauxBDBzSyN2+Yu+KJxw0oxrrJyuPW8NpELs"
},
"is_state": false,
"origin": "matrix.org",
"pdu_id": "rKQFuZQawa",
"pdu_type": "m.room.message",
"prev_pdus": [
["PaBNREEuZj", "matrix.org"]
],
"signatures": {
"matrix.org": {
"ed25519:auto": "jZXTwAH/7EZbjHFhIFg8Xj6HGoSI+j7JXfIcPFDWl1pdJz+JJPMHTDIZRha75oJ7lg7UM+CnhNAayHWZsUY3Ag"
}
},
"origin_server_ts": 1413414391521,
"user_id": "@matthew:matrix.org"
}]
}’ https://alice.com:8448/_matrix/federation/v1/send/916d630ea616342b42e98a3be0b74113 34

35. Application Services (AS)
• Extensible custom application logic
• They have privileged access to the server (granted by the admin).
• They can subscribe to wide ranges of server traffic (e.g. events
which match a range of rooms, or a range of users)
• They can masquerade as 'virtual users'.
• They can lazy-create 'virtual rooms'
• They can receive traffic by push.
35

36. A trivial application service
import json, requests
from flask import Flask, jsonify, request
app = Flask(__name__)
@app.route("/transactions/<transaction>", methods=["PUT"])
def on_receive_events(transaction):
events = request.get_json()["events"]
for event in events:
print "User: %s Room: %s" % (event["user_id"], event["room_id"])
print "Event Type: %s" % event["type"]
print "Content: %s" % event["content"]
return jsonify({})
if __name__ == "__main__":
app.run()
36

37. Matrix Bridging with ASes
Existing App
Application
Service
3rd party
Server
3rd party
Clients

38. Matrix to PSTN
matrix-
appservice-verto
FreeSWITCH
PSTN
Numbers

39. Matrix to IRC
matrix-
appservice-irc
ircd
(e.g. Freenode)
IRC
clients

40. Matrix to
matrix-
appservice-slack
slack.com
Slack
clients

41. to IRC
IRC
clients
Slack
clients

42. Matrix Bridge Stack
42
matrix-
appservice-
irc
matrix-appservice-bridge
matrix-appservice-node
matrix-js-sdk
Node JS
matrix-
appservice-
slack
matrix-
appservice-
purple …

43. We need your help!

44. • We need people to try running their own
servers and join the federation.
• We need people to run gateways to their
existing services
• We need feedback on the APIs.
• Consider native Matrix support for new
apps
• Follow @matrixdotorg and spread the
word!
44

45. 45
The end goal:

46. Thank you!
kegan@matrix.org
http://matrix.org
@matrixdotorg
46