Functional requirements (FR)

• Create sessions or shared spaces and let authorized participants join, leave, and view current state.
• Accept user actions and propagate relevant state changes to other participants.
• Support reconnection, state recovery, and history or audit views where required.
• Enforce participant permissions and domain rules during concurrent actions.

Non-functional requirements (NFR)

• Define interaction latency, ordering, conflict resolution, and consistency expectations.
• Support reconnects and partial network failure without silently losing accepted changes.
• Scale concurrent sessions and participants while isolating abusive or overloaded sessions.
• Protect private content and provide operational visibility into synchronization health.

Principal-level discussion

• Define the scale, success measures, and operational ownership before committing to an architecture.
• Compare at least two viable approaches and explain the trade-offs, migration path, and failure behavior.
• Identify the riskiest assumptions and how you would validate them with data or a staged rollout.