WebSocket

Outcome: Design or review WebSocket for this system while keeping data correct, secure, and easy to operate. User context: Two teammates edit one board. Each saved move reaches the other screen through the open connection. Technical concept or control: WebSocket. Why it fits: Use it for chat, collaboration, or live events that need messages in both directions. Do not use it when: Use a normal request for an occasional simple read. WebSocket has no built-in authentication, so your app must add access checks and recovery rules. Engineering requirements: Define inputs, outputs, contracts, and rules that must always hold. Set authorization and input checks. Define failures, timeouts, retries, one-time effects, data moves, and compatibility limits. Operations: Add useful signals and logs that hide sensitive data. Set capacity limits and write an operator guide. Test recovery and rollback. Acceptance criteria: Contract and failure-path tests pass. Data and authorization rules still hold during retries and partial failures. Check performance limits, monitoring, recovery, and rollback. Evidence and limits (evidence boundary): The standard covers only the listed scope. It does not choose the visual style, product decision, or Vibulary example. Unknowns to confirm: Where the code runs, data stores, traffic shape, consistency needs, and the security boundary. Also confirm the compatibility period, service goals, and rollback limits.