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Asana·Software Engineer·Onsite - System Design / Architecture·Senior

SeniorPrefer not to say
May 2026

Summary

Interviewed at Asana for a backend/infrastructure-leaning engineering role. One system design question, pretty focused session, no small talk.

Questions Asked (1)

Q1

How would you optimize a Content Distribution Network (CDN)?

System DesignTechnical Trade-offs
Author's notes

I started with caching strategies and edge node placement, which felt right, but I think I spent too long on cache invalidation and never got to load balancing or geo-routing in any real depth.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the goals and constraints of the CDN optimization, such as improving performance, reducing costs, or increasing reliability. Then walk through a structured optimization framework covering caching, edge computing, network protocols, and monitoring, while discussing trade-offs for each decision. Finally, tie your answer back to Asana's specific needs, such as handling static assets for a collaborative work management platform.

Pro tip: Emphasize that optimization is an ongoing process: measure first, then optimize, and always validate improvements with real user metrics like Time to First Byte (TTFB) and cache hit ratio. Also, mention that you'd consider the cost implications of each optimization, as CDN costs can scale significantly with traffic.

1. Clarify Goals and Constraints

Ask questions to understand the primary objectives (e.g., latency reduction, cost savings, scalability) and constraints (budget, existing infrastructure, security requirements). This ensures your optimization aligns with business needs.

2. Optimize Caching Strategy

Review and improve cache policies: set appropriate TTLs, use cache-control headers, implement cache purging, and consider tiered caching (edge and mid-tier). Also, leverage stale-while-revalidate and stale-if-error for resilience.

3. Leverage Edge Computing and Protocols

Move logic to the edge using serverless functions (e.g., Cloudflare Workers) to reduce origin load. Adopt modern protocols like HTTP/3, QUIC, and TLS 1.3 to reduce latency and improve security.

4. Optimize Content and Delivery

Compress assets (Brotli, Gzip), optimize images (WebP, AVIF), and minify code. Use techniques like prefetching, preloading, and early hints to speed up delivery. Consider dynamic content acceleration via optimized routes.

5. Monitor, Measure, and Iterate

Set up real-time monitoring and analytics (e.g., cache hit ratio, TTFB, error rates). Use A/B testing to validate changes and continuously iterate based on data.

Key Points to Mention

  • Cache hit ratio and TTL optimization
  • Edge computing and serverless functions at the edge
  • HTTP/3, QUIC, and TLS 1.3 for reduced latency
  • Content compression and image optimization
  • Real-user monitoring (RUM) and synthetic monitoring
  • Cost-performance trade-offs and multi-CDN strategies

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.