Backend Language Proficiency Questions

Demonstrate strong practical knowledge of a backend programming language such as JavaScript with Node dot js, Python, Java, Go, or similar. Cover language fundamentals, idiomatic usage, standard library features, package and dependency management, common frameworks and ecosystem tools, testing strategies and tooling, error handling and observability, and patterns for maintainable server side code. Be ready to explain concurrency and asynchronous models in the language, performance considerations, security best practices, deployment and packaging approaches, and examples of backend services or APIs you built including trade offs and chosen libraries.

EasyTechnical

0 practiced

Describe the concurrency model of two backend languages of your choice (for example Go goroutines+channels vs Node.js event loop vs Java threads+executors vs Python threading+asyncio). For each, explain how you would implement a background worker pool that processes jobs and safely coordinates shutdown during deployment.

MediumTechnical

0 practiced

Given a microservice in your language that serializes and deserializes protobuf messages, describe how to handle schema evolution safely: adding/removing fields, default values, unknown fields, and breaking changes. Provide code or configuration examples that show backward and forward compatibility handling.

HardTechnical

0 practiced

Implement a file or network-based lock in your language that can be used to coordinate singleton operations across processes (e.g., leader election for a maintenance job). Explain failure modes when the process holding the lock crashes and how to choose TTLs or use lease renewal safely.

EasyTechnical

0 practiced

Create a minimal example showing how to perform dependency freezing / vendor locking for your language (for example, pipenv/requirements.txt + wheelhouse for Python, go mod vendor, npm shrinkwrap for Node). Explain how this helps with reproducible builds and emergency rollbacks when an upstream package has a regression or security issue.

EasyTechnical

0 practiced

As an SRE, you must ensure service observability. Describe the differences and relationships between logs, metrics, and distributed traces for backend services. Give one concrete example in your language of how you would instrument a critical API endpoint to produce all three and explain how they complement each other in incident response.

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