Task library LIVE Real-time systems · Phased project A collaborative incident room with a reliable timeline The fictional Harbor operations team coordinates synthetic incidents in a shared room. Engineers post status notes and claim response tasks while connections come and go. Scope is one application gateway, a durable room event store, and fixture clients; alert paging and external chat delivery are excluded.
Practice brief · Version 5
Project scope 10 tickets / 4 phases
Total focused work estimate 23h 45m + setup
Suggested stack TypeScript · Node.js · WebSocket · PostgreSQL · Redis Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included.
Choose a bounded subset for an assessment or practice session. Prerequisites and remaining project work must be agreed separately.
Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence.
Pattern topics identify design choices to practice. Read the ticket's acceptance criteria and justify the simplest suitable approach. Tags are not capability or ownership evidence; an untagged ticket has no curated pattern topic assigned.
Recommended next step Start with LIVE-101 Open the first ticket for its prerequisites, acceptance criteria, verification plan, and an editable task draft.
What the engineer takes away Practice event identity, ordering, replay, authorization, and bounded backpressure in one understandable system.
What the team gains Inspect how an engineer keeps collaborative state trustworthy during failures without relying on optimistic success messages.
Before you start Room membership and command contracts Synthetic incident events and a controllable transport harness Delivery agreement Deliver one issue or a phase at a time against synthetic rooms. Keep load fixtures bounded and avoid real incident channels.
AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior.
Delivery phases PHASE 1 Make connection state and event boundaries explicit.
PHASE 2 Order, deduplicate, and replay confirmed events.
PHASE 3 Protect commands, presence, and changing access.
PHASE 4 Bound resource use and rehearse recovery.
Establish the room contract Make connection state and event boundaries explicit.
LIVE-101 Entry ticket; project setup still required Estimated field mix
Real-time systems 60% Frontend 40% LIVE-102 Entry ticket; project setup still required Estimated field mix
Real-time systems 50% API design 30% Security 20% LIVE-103 Depends on LIVE-102 Estimated field mix
Security 60% Real-time systems 40% Recover a coherent timeline Order, deduplicate, and replay confirmed events.
LIVE-104 Depends on LIVE-101, LIVE-102, LIVE-103 Estimated field mix
Real-time systems 60% Distributed systems 40% LIVE-105 Depends on LIVE-104 Estimated field mix
Real-time systems 60% Distributed systems 40% Coordinate work safely Protect commands, presence, and changing access.
LIVE-106 Depends on LIVE-105 Estimated field mix
Real-time systems 40% Backend 30% Database engineering 30% LIVE-107 Depends on LIVE-103 Estimated field mix
Real-time systems 70% Distributed systems 30% LIVE-108 Depends on LIVE-105, LIVE-106, LIVE-107 Estimated field mix
Security 60% Real-time systems 40% Handle operational pressure Bound resource use and rehearse recovery.
LIVE-109 Depends on LIVE-105, LIVE-108 Estimated field mix
Performance engineering 50% Real-time systems 50% LIVE-110 Depends on LIVE-106, LIVE-108, LIVE-109 Estimated field mix
Real-time systems 40% Site reliability 30% Quality engineering 30% Use this project CSV keeps grouping and dependency keys as descriptive fields. Import mapping depends on your tracker configuration.