Seamless Direct and Group Calling Without Pre-existing Rooms

[RebaseYourExpectations]

What would you like to do?

I would like to initiate voice/video calls to any Matrix user or group of users without requiring a pre-existing room. Currently, Element Call requires manual room creation and invitation acceptance before any call can begin, creating a significant barrier to spontaneous communication.

Current unpleasant workflow:

1. Search for contact(s)
2. Create DM/room
3. Hope they notice the room
4. Wait for invitation acceptance
5. Finally start call

Desired workflow:

1. Click call button on any contact
2. They receive incoming call notification
3. Call connects

Why would you like to do it?

This limitation makes Element Call unsuitable as a primary VoIP solution for organizations and individuals who need:

1. Emergency Communications: Security teams need instant contact with any employee
2. Customer Service: Support staff must call users without pre-chat setup
3. Sales Operations: Outbound calls to new contacts are impossible
4. Healthcare: Medical staff need immediate colleague consultation
5. Cross-team Collaboration: Spontaneous calls between users

Real-world impact examples:

• IT Incident Response: "Server down, need to call on-call engineer" - Cannot reach them without existing room
• Medical Emergency: "Code call, assemble trauma team" - Must individually invite each doctor first
• Business Development: "Quick call with prospective client" - Requires awkward "accept my chat first" conversation
• Private Scenarios: "Call specific group of friends for an event" - Must create room probably days in advance for every one to be able to join.

This represents a severe adoption blocker when organizations evaluate Element against Teams, Zoom, or traditional phone systems. As well as private users searching a replacement for systems like WhatsApp.

How would you like to achieve it?

Implement Seamless Auto-Join functionality that creates rooms transparently during call initiation.

Configuration options:

• Server-level: Enable/disable seamless calling per homeserver
• Federation policy: Control cross-server call permissions
• User preferences: Opt-out of receiving seamless calls
• Admin controls: Allowlist for seamless calling domains

Technical approach:

1. Extend m.call.invite to include auto-join tokens
2. Create (ephemeral) rooms (with special retention policies)
3. Implement "ring-first, join-later" notification flow

Have you considered any alternatives?

** Alternative 1: Pre-create Rooms for Everyone**
Automatically create DM rooms with all possible contacts. Rejected: Scales terribly, clutters room list, privacy concerns. Not possible for group calls.

** Alternative 2: External Call Routing**
Use SIP/PSTN for contact. Rejected: Breaks E2EE, requires additional infrastructure, defeats Matrix-native approach.

** Alternative 3: Accept Current Limitations**
Train users on current workflow. Rejected: Users expect click-to-call functionality. Does not satisfy requirements.

Additional context

Implementation Benefits

For Organizations:

• Instant employee reachability
• Emergency response readiness
• Reduced onboarding friction
• Familiar calling patterns

For Matrix Ecosystem:

• Increased adoption in enterprise
• Competitive parity with centralized platforms
• Gateway to Matrix for voice-first users
• Showcase of protocol flexibility

** Consent mechanisms: **

• Global "accept calls from" settings (everyone/contacts/nobody)
• Per-domain allowlists for federated calls
• Block lists inherited from existing Matrix ignore functionality

** Federation Considerations**

• Respect remote server policies
• Clear capability negotiation

[toger5]

Extend m.call.invite to include auto-join tokens

The event can only be received if the user is already part of the room. So this is not the approach that would solve this.

This would need to be solved by adding the ring information to the invite event. that is the only data we can send to foreign users via their sync loop without having a shared room.

It is also very important to mention the possible attack/abuse such a functionality would offer. It basically allows any stranger in the internet to make all devices from an completely unrelated user on matrix ring.

So this would at least need some kind of filtering/whitelisting that is very hard to get right.

If you want to help on this, you can extend the issue with those aspects aspects and maybe propose solutions for how the client can decide if it should actually ring on an notify event or not.

I have thought about this a bunch but have not yet found a satisfactory solution.