Coinbase DevOps / SRE Interview Questions

1.Walk me through a time when you had to debug a performance issue that was affecting users. How did you approach it and what was the outcome?

2.Tell me about a time you saw inefficient operational practices on your team and took initiative to automate or improve them. What did you build and what was the impact?

3.Tell me about a time you had to choose between fixing a critical production issue quickly versus implementing a more robust long-term solution. What was the situation and how did you decide?

4.Tell me about a time you implemented a change to your team's processes or tools that significantly improved how everyone worked. What was broken and how did you fix it?

5.Describe a time when you noticed a critical infrastructure problem that wasn't technically your responsibility, but you stepped in to solve it anyway. What was the issue and what did you do?

6.Describe a situation where you had to advocate for a security or compliance change that would slow down a product launch. How did you handle the pushback?

7.We need to migrate our user authentication service from Ruby to Go for better performance. How would you plan this migration while maintaining 24/7 uptime for our trading platform?

8.You're setting up monitoring for our new Base blockchain RPC endpoints that serve external developers. What key metrics would you track and why?

9.You need to deploy a microservice update to production, but it touches both our trading engine and our compliance logging system. Walk me through your deployment strategy.

10.Our PostgreSQL database is showing 90% CPU utilization during peak trading hours. The team wants to add more read replicas, but you suspect there's a deeper issue. How do you approach this?

11.Our Kubernetes cluster runs blockchain nodes that need to stay in sync with the network. A deployment rollout is causing some nodes to fall behind by 100+ blocks. How would you investigate and fix this without impacting trading?

12.A critical trading API is returning 500 errors for about 2% of requests, but only during high-volume periods. How would you debug this intermittent issue?

13.Design a real-time alert system that can notify our SRE team when any of our 50+ blockchain nodes across Bitcoin, Ethereum, and Base fall more than 10 blocks behind. The system needs to handle 100k+ block events per minute during peak network activity.

14.Design a secrets rotation system for our entire microservices platform that can automatically rotate database passwords, API keys, and TLS certificates for 500+ services without causing outages. The system must meet SOC 2 compliance and handle emergency rotation scenarios.

15.We're launching Coinbase Cloud's new staking-as-a-service offering where enterprise customers can stake their ETH through our infrastructure. Design the capacity planning and auto-scaling system for validator nodes that need to handle $2B+ in staked assets while maintaining 99.9% uptime.

16.Design a circuit breaker system for Coinbase Prime's trading APIs that can automatically halt trading when we detect unusual market conditions or potential security incidents. The system needs to work across 200+ trading pairs with microsecond latency requirements.

17.Our Coinbase Exchange needs to implement dynamic fee calculation that adjusts trading fees in real-time based on market conditions, user tier, and network congestion. Design a system that can handle 100k+ fee calculations per second while ensuring consistency across all trading pairs.

18.Design the infrastructure automation system for our Base blockchain that can automatically provision new validator nodes, configure networking, and deploy smart contract updates across our testnet and mainnet environments while maintaining zero downtime for the network.

19.Tell me about a time you identified that your team's on-call practices weren't sustainable and took action to improve them. What changes did you make?

20.Describe a situation where you disagreed with a senior engineer or architect about an infrastructure approach, but you still needed to work together to deliver. How did you handle it?

21.Tell me about a time you had to convince engineers from multiple teams to adopt a new infrastructure standard or practice. How did you get buy-in without having direct authority over them?

22.Walk me through a time when you had to learn a new blockchain or crypto technology quickly to solve an infrastructure problem. How did you approach the learning process?

23.Describe a time when you had to make a difficult infrastructure decision during a critical incident that affected customer trading. Walk me through your thought process.

24.Tell me about a time you took ownership of improving security practices in your infrastructure work, even though security wasn't officially part of your role. What motivated you and what did you accomplish?

25.Estimate how much compute capacity we'd need to provision if Coinbase Exchange trading volume suddenly doubled overnight. Walk me through your assumptions and calculations.

26.A major DeFi protocol wants to integrate with Coinbase Prime for institutional liquidity, but their smart contract calls our API 50,000 times per minute. How would you evaluate whether our current API infrastructure can handle this integration?

27.Our compliance team needs to generate regulatory reports that require scanning 6 months of blockchain transaction data across Bitcoin, Ethereum, and Base. How would you architect this without impacting our real-time trading systems?

28.We're seeing intermittent 5-second delays in our deposit confirmation system, but only for Ethereum transactions during network congestion. Walk me through how you'd diagnose this issue.

29.Estimate the infrastructure cost impact if we enabled real-time price alerts for all 10 million Coinbase users across 200+ trading pairs. What would be the most expensive component?

30.Our Base blockchain network is experiencing 30% higher gas usage than Ethereum for similar transactions. How would you investigate whether this is a problem with our L2 implementation or expected behavior?