Luca Brunner·
Sketched a CRDT-based collab editor and explained exactly why Yjs beats OT for scaling to a million sockets
Generates a complete system architecture blueprint including component diagrams, data flow, integration points, and technology recommendations tailored to your requirements.
Design System Architecture from Scratch
Act as a Principal Software Architect with 20 years of experience designing large-scale distributed systems. I need you to design a complete system architecture for the following:
**System Type**: {{system_type}}
**Scale Requirements**: {{scale_requirements}} (e.g., 10M daily active users, 100K RPM)
**Tech Constraints**: {{tech_constraints}} (e.g., must use AWS, compliance requirements, existing tech stack)
**Budget**: {{budget}} (monthly infrastructure budget)
Provide the following in your response:
1. **High-Level Architecture Diagram** - Describe using ASCII/text art or Mermaid diagram syntax the overall system layout
2. **Component Breakdown** - List each service/component with its responsibility and chosen technology
3. **Data Flow** - Trace the journey of a typical request from client to database and back
4. **Technology Justification** - Explain why each technology was chosen with 2-3 pros/cons alternatives considered
5. **Scalability Strategy** - How each component scales independently under load
6. **Integration Points** - External APIs, third-party services, and internal service communication patterns
7. **Failure Scenarios** - Top 5 failure modes and how the architecture handles them
8. **MVP vs Final Architecture** - What changes between initial launch and full scale
9. **Cost Breakdown** - Estimated monthly infrastructure cost per component at target scale
10. **Risk Assessment** - Technical risks and recommended mitigations
Be specific with version numbers, instance types, and concrete configurations. Do not use vague recommendations.
Ergebnisse
## Architecture — Real-time collaborative document editor (target: 1M concurrent users)
**Constraints assumed:** AWS, ~10k RPM steady writes, sub-100ms edit propagation, ~$8k/mo infra budget.
```
┌──────────┐
Browsers ──WSS──▶ │ ALB │
└────┬─────┘
┌───────────┴───────────┐
┌─────▼─────┐ ┌─────▼─────┐
│ Edge WS │ ...... │ Edge WS │ (Node + y-websocket, autoscaled)
│ gateway │ │ gateway │
└─────┬─────┘ └─────┬─────┘
└──────── Redis Pub/Sub ─┘ (fan-out across gateways)
│
┌──────▼───────┐
│ CRDT service │ ──▶ Postgres (doc snapshots)
└──────────────┘ ──▶ S3 (version history)
```
**Component breakdown:**
| Component | Tech | Responsibility |
|-----------|------|----------------|
| Edge WS gateway | Node 20 + `y-websocket` | holds socket connections, relays CRDT updates |
| Sync fabric | Redis 7 Pub/Sub | broadcasts edits between gateways |
| CRDT service | Rust + `yrs` (Yjs port) | merges concurrent edits conflict-free |
| Snapshot store | Postgres 16 | latest doc state + metadata |
**Why CRDT over OT:** Yjs/`yrs` gives conflict-free merges without a central sequencer, so any gateway can accept a write — that's what makes horizontal scaling to 1M sockets feasible. OT would need a single ordering authority per doc (a bottleneck). Trade-off: CRDTs carry more metadata, mitigated by periodic snapshot compaction to S3.
**Scaling:** gateways are stateless (sockets only) and scale on connection count; Redis Pub/Sub fans out edits; the CRDT service shards by `docId`. **Top failure mode:** a Redis partition splits gateways — handled by each gateway persisting to Postgres independently and reconciling via CRDT merge on reconnect, so no edits are lost. **MVP cut:** single gateway + Postgres `LISTEN/NOTIFY` instead of Redis until ~10k concurrent, then introduce the Pub/Sub fabric.
Modell: Claude Opus 4
21 Likes7 SavesScore: 18
1 Kommentar
Ryan Mitchell·
I'd ship this as-is. Maybe rename one var, that's it.