Go for infrastructure and high-throughput services, where concurrency idioms carry most of the interview weight.
8 published across 4 topics.
Slices and maps internals, interfaces and embedding, error handling conventions, and generics.
A Go interface is non-nil when it holds a concrete type, even if the concrete pointer value is nil. Returning a typed nil pointer as an error creates an interface value that fails err == nil checks.
Go slice append either extends the existing backing array or allocates a new one when capacity is exhausted. Bugs appear when two slices share the same array and one append mutates data the other still observes.
The scheduler, channel semantics, select, context cancellation, and detecting goroutine leaks.
A goroutine leak in Go happens when a goroutine blocks forever on a send, receive, network call or abandoned worker path. Find it with goroutine counts and pprof, then add cancellation to every blocking operation. Use this goroutines answer to show the decision, trade-off, and evidence rather than a memorised definition. It also connects channels to the point an interviewer is testing.
In Go, the sender closes a channel when no more values will be sent; receivers do not close it just because they are done. Multiple senders need coordination so close happens exactly once after all sends finish. Use this channels answer to show the decision, trade-off, and evidence rather than a memorised definition. It also connects goroutines to the point an interviewer is testing.
Escape analysis, allocation reduction, GC behaviour, and pprof-driven profiling.
Escape analysis moves a value to the heap when the compiler cannot prove its lifetime ends with the frame that created it, and go build -gcflags=-m prints every decision. Which of those allocations matter is a measurement question, answered with a benchmark, an alloc_space profile and benchstat.
Take a heap profile and compare two taken minutes apart, because the shape of the growth tells you whether it is a leak, a cache with no bound, or simply the collector letting the heap grow. The two real knobs are GOGC and GOMEMLIMIT, and reducing allocation matters more in Go than in a generational runtime.
Standard-library HTTP, project structure, dependency management, and testing patterns.
Go context cancellation stops wasted request work when the client disconnects or a timeout expires. Pass the request context into database, HTTP and worker calls, and make goroutines return when ctx.Done closes.
Wire dependencies explicitly through constructors from one place in main, define narrow interfaces where they are consumed rather than implemented, and keep handlers thin enough that the logic beneath is testable without a server. With no framework, these are decisions rather than defaults.