Perfect. Below is a complete structured interview document you can use for your 1-hour Senior Engineer (AWS + Golang) interview.
It combines: ✅ The 6 structured phases (increasing difficulty) ✅ Theory, scenario, and practical questions ✅ Coding questions (for notepad) ✅ Short reference answers for each question — so you can easily gauge how well the candidate’s responses align with what’s expected.
🧩 Senior Engineer (AWS + Golang) — 1 Hour Technical + Leadership Interview 🕒 Interview Breakdown Phase Duration Focus 1 5 min Introduction & project ownership 2 10 min AWS + Go fundamentals 3 15 min System design scenarios 4 15 min Debugging & problem-solving 5 10 min Leadership & ownership 6 5 min Wrap-up
- — Coding Questions (mix into Phase 3 or 4)
🔹 PHASE 1 — Introduction (5 mins)
Q1: Tell me about one project where you owned end-to-end delivery using AWS and Go.
Expected Answer: Should highlight complete ownership — from architecture to deployment — using AWS services like Lambda, ECS, or EC2, and Go for backend logic. Should mention CI/CD, monitoring, and cost optimization. A good candidate emphasizes design decisions, trade-offs, and outcomes (e.g., performance gains, cost savings).
Follow-up:
“What would you do differently now?” → Looks for introspection and evolution in design choices.
“Which part only you understood deeply?” → Tests unique expertise and ownership instincts.
🔹 PHASE 2 — AWS + Go Fundamentals (10 mins)
Q2: Design a scalable API using AWS components.
Expected Answer: Should mention Load Balancer (ALB), API Gateway, Lambda/ECS (Go runtime), RDS/DynamoDB, S3, and CloudWatch. Mentions security layers (IAM, VPC, SGs). Good engineers mention autoscaling, fault tolerance, and CI/CD deployment with CodePipeline or Terraform.
Follow-ups:
Use IAM roles, VPCs, or PrivateLink for secure service comms.
Region-level resilience through multi-region failover or Route53.
Lambda timeout debugging using CloudWatch logs and X-Ray.
Q3: Explain goroutines and channels in Go.
Expected Answer: Goroutines are lightweight threads managed by Go runtime; channels synchronize and share data safely. The candidate should mention avoiding global state and using select for multiplexing.
Follow-ups:
[]rune for Unicode correctness.
-race flag for detecting race conditions.
Awareness of goroutine leaks and context cancellations.
🔹 PHASE 3 — Scenario-Based System Design (15 mins)
Q4: Design a logging pipeline for multiple microservices (AWS + Go).
Expected Answer: Use Kinesis Firehose or Kafka → Lambda (Go) → S3 → Glue/Athena for queries. Add CloudWatch logs for monitoring and IAM for permissions. Mentions schema evolution or partitioning in S3 for efficient querying.
Follow-ups:
Handle out-of-order logs with timestamp sorting.
Avoid duplicates via deduplication key or DynamoDB state.
Scalability test using load simulation or AWS FIS.
Multi-region via cross-region replication in S3.
Q5: Structuring a Go project using AWS SDKs.
Expected Answer: Use clean architecture: cmd/, pkg/, internal/. Maintain AWS sessions centrally; dependency inject clients. Mock AWS SDK with interfaces for tests.
Follow-ups:
Manage session reuse to prevent overhead.
Use gomock or testify for mocking SDKs.
🔹 PHASE 4 — Debugging & Problem Solving (15 mins)
Q6: ECS Fargate service shows high latency — how to debug?
Expected Answer: Start with CloudWatch metrics (CPU, memory, network). Check container logs, analyze X-Ray traces, and verify DB latency. Check connection pooling, goroutine blocking, or DNS resolution delay.
Follow-ups:
Differentiate network vs code issues via VPC Flow Logs or profiling.
Time-specific issues hint at autoscaling or DB throttling.
Q7: S3 costs suddenly doubled — what’s your plan?
Expected Answer: Check AWS Cost Explorer, S3 Storage Lens, and CloudTrail for changes. Investigate versioning or unexpired lifecycle policies. Enable intelligent tiering.
Follow-ups:
Automate cost enforcement using IaC and lifecycle policies.
Use AWS Config for detecting public buckets.
Q8: Deploy & roll back a Go microservice via CI/CD.
Expected Answer: Use CodePipeline + CodeDeploy (blue/green). Terraform for infra. Maintain versioned artifacts in S3 or ECR. Implement rollback through version tags.
Follow-ups:
Handle DB schema migrations with pre/post deploy steps.
Rollback failure = resource conflict → automate cleanup.
🔹 PHASE 5 — Leadership & Ownership (10 mins)
Q9: You lead 4 engineers — how do you start from scratch?
Expected Answer: Establish coding standards, Git branching, sprint rituals, CI/CD pipelines, and lightweight documentation. Prioritize backlog, define MVP, and ensure local setup works for all.
Follow-ups:
First week = repo setup, pipeline, code review rules.
Handling underperformers = mentorship + pairing + clear goals.
Teaching juniors: review-based learning and pair debugging.
Q10: PM changes requirements mid-sprint — what’s your move?
Expected Answer: Reassess impact, communicate clearly to team and PM, adjust sprint scope if needed. Maintains delivery while protecting morale.
Follow-ups:
Balance delivery vs flexibility.
Propose feature flags to decouple delivery from requirements.
🔹 PHASE 6 — Wrap-Up (5 mins)
Q11: What’s one AWS or Go concept you learned recently?
Expected Answer: Should mention something advanced like Lambda SnapStart, Step Functions, Go generics, or context propagation.
Follow-ups:
How do you help your team stay updated?
Mention of internal knowledge-sharing is a plus.
⚙️ CODING QUESTIONS (For Notepad)
You can ask 2–3 of these in the middle (Phases 3–4).
- Reverse a string
func Reverse(s string) string {
r := []rune(s)
for i, j := 0, len(r)-1; i < j; i, j = i+1, j-1 {
r[i], r[j] = r[j], r[i]
}
return string(r)
}✅ Should handle Unicode properly.
Follow-up: Why rune instead of byte?
- Write a Go function that counts occurrences of each word in a given sentence.
package main
import (
"fmt"
"strings"
)
// CountWordOccurrences counts the occurrences of each word in a given sentence.
// It returns a map where keys are the words and values are their respective counts.
func CountWordOccurrences(sentence string) map[string]int {
// Convert the sentence to lowercase to treat "The" and "the" as the same word.
lowerSentence := strings.ToLower(sentence)
// Split the sentence into words using whitespace as a delimiter.
// strings.Fields handles multiple spaces and trims leading/trailing spaces.
words := strings.Fields(lowerSentence)
// Create a map to store word counts.
wordCounts := make(map[string]int)
// Iterate over the words and increment their counts in the map.
for _, word := range words {
wordCounts[word]++
}
return wordCounts
}
func main() {
sentence := "Go is a great language. Go is fun to learn."
counts := CountWordOccurrences(sentence)
fmt.Println("Word occurrences:")
for word, count := range counts {
fmt.Printf("'%s': %d\n", word, count)
}
sentence2 := "Hello world, hello Go!"
counts2 := CountWordOccurrences(sentence2)
fmt.Println("\nWord occurrences for second sentence:")
for word, count := range counts2 {
fmt.Printf("'%s': %d\n", word, count)
}
}Follow-up: When use sync/atomic instead?
simple coding
- Variable Shadowing
Question: What is the output of the following snippet?
package main
import "fmt"
func main() {
x := 10
if true {
x := 20
fmt.Println(x)
}
fmt.Println(x)
}Expected Answer:
20 10
Explanation: The inner x := 20 declares a new variable shadowing the outer one — scope ends with the block.
Follow-up:
What happens if you use x = 20 instead of x := 20?
- Nil Interface Trick
Question: What is the output?
package main
import "fmt"
func main() {
var x *int = nil
var i interface{} = x
if i == nil {
fmt.Println("nil interface")
} else {
fmt.Println("non-nil interface")
}
}Expected Answer:
non-nil interface
Explanation: The interface i holds a typed nil (*int(nil)), which means the interface itself isn’t nil — both type and value must be nil for the interface to be nil.
Follow-up:
How can you check if the underlying value of an interface is nil?
- Slice Backing Array Trap
Question: What will be printed here?
package main
import "fmt"
func main() {
s := []int{1, 2, 3}
t := s
t[0] = 100
fmt.Println(s)
}Expected Answer:
[100 2 3]
Explanation: Slices share the same backing array; modifying one changes all references.
Follow-up:
How can you make a true copy so s isn’t affected?
- Deferred Function Execution
Question: Predict the output:
package main
import "fmt"
func main() {
for i := 0; i < 3; i++ {
defer fmt.Println(i)
}
}Expected Answer:
2 1 0
Explanation: Deferred functions execute in LIFO order after main() returns.