Cases: turning architecture from answer into reasoning
tutorial/teaches the method,templates/gives you maps, andcases/walks a concrete product from zero to launch, then into real pressure.
The case track is not "more templates." Templates answer: what does this kind of system usually look like? Cases answer: in one concrete situation, why did the architecture get forced into this shape?
First batch
| Case | Related templates | What it drills |
|---|---|---|
| 01 · StarArena: a 20,000-seat concert ticketing system | Online Ticketing / Ticket Rush · E-commerce Platform · Payment System | Limited inventory, virtual waiting room, seat locking, payment state machine, reconciliation and compensation |
| 02 · PatchDesk: a lightweight ticketing SaaS for 20-person teams | Standard Web App · Mobile App · Notification System | Modular monolith, tenant isolation, RBAC, ticket timeline, Outbox, async notifications, search/report evolution |
| 03 · DocuMind: an enterprise RAG knowledge base for a 500-person company | RAG Knowledge Base · AI Chat Product · Vector Database | Document ingestion, chunking, hybrid retrieval, Graph RAG, reranking, citations, permission filtering, prompt injection, eval regression |
| 04 · SyncRoom: a realtime collaboration workspace for remote teams | Realtime Chat · Collaborative Doc · Notification System | Long connections, server seq, offline catch-up, multi-device sync, OT / CRDT, presence, notification degradation |
| 05 · FeedStream: social feed and video content distribution | Social Feed · Video Streaming · Search Engine | Hybrid fanout, top creator fanout, timeline inboxes, recommendation ranking, search indexes, video transcoding, CDN, moderation recall |
| 06 · CodePilot: an AI Agent / coding Agent platform | AI Agent / Workflow Platform · OpenAI Codex · Claude Code | Tool calls, permission gateway, sandboxing, human approval, context compaction, checkpoints, subagents, trace, eval gates |
The first batch of six core cases closes here. Later cases will extend with the same quality bar into industry depth or technology-stack drills.
How to read cases
Do not memorize the diagram. Watch four things:
- Why was the old architecture reasonable at first?
- Which quantified signal proved it could no longer continue?
- What did the new architecture choose, and what did it give up?
- If the constraints changed, would this answer still hold?
One-line bar:
No numbers, not a case; no trade-offs, not architecture; no evolution, not case-track material.
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