System Architecture Explainer

Provides a clear, opinionated system architecture recommendation with tradeoffs and a phased roadmap.

Best For

•Founding engineers deciding on a stack before writing the first line of a new product.
•Engineering managers preparing a design doc who want a second opinion on tradeoffs before a team review.
•Developers moving from a side project to real users who need a phased plan for handling growth without over-engineering early.

Prompt Template

I'm building [SYSTEM DESCRIPTION, e.g. 'a real-time chat application', 'a multi-tenant SaaS platform']. My expected scale: [SCALE, e.g. '10,000 DAU', '100 requests/second']. Current tech stack: [STACK]. Explain the recommended architecture for this system, covering: (1) a high-level architecture diagram described in text (components, how they connect, data flow), (2) the right database choice(s) and why (SQL vs NoSQL, caching layer), (3) key architectural patterns to apply (microservices vs monolith, event-driven, CQRS, etc.) and the tradeoff for each, (4) the 3 biggest scalability risks in this design and how to mitigate them, (5) a phased build plan: what to build in Phase 1 (MVP), Phase 2 (growth), and Phase 3 (scale). Be opinionated and practical.

Pro Tip

Give a realistic current scale and a realistic 12-month target scale, not just 'it needs to scale,' since vague scale targets produce vague, unhelpful architecture advice.

Example Output

A sample of what this prompt produces once you fill in the placeholders.

For a real-time chat app at 10,000 DAU on a Node.js/Postgres stack, the output recommends Postgres plus Redis for presence and pub/sub, an event-driven pattern for message delivery over a strict microservices split, flags connection-scaling and message-ordering as the top two risks, and lays out an MVP-to-scale phased plan starting with a single WebSocket server.