What should I focus on for a microservices interview?
Which questions should I start with?
Start with choosing between a monolith and microservices. This was the most asked question, appearing in 20 of 131 interviews. Basics and communication were the most common topics, each covered in 38 of 131 interviews.
Can you explain what microservices are, their benefits, and their drawbacks? Check that you can say when you would keep a monolith, not just why you would split it into services. Your answer should explain a choice, rather than only give a definition.
Can I explain why I chose each service boundary?
Reviews of real answers found missing explanations of service boundaries based on business domains, data ownership, and team responsibilities. Scaling needs alone did not cover these points.
Check your design answer:
- What is each service responsible for, and which business domain does it cover?
- Which data does it own, and which team is responsible for it?
- If moving from a monolith, how would you extract a service and reduce compatibility risks?
Can I walk through a request between services?
Reviewed answers also missed a concrete explanation of how services communicate, such as HTTP/REST or brokered messaging.
Walk through a request instead of listing tools. Which service calls which? How does that call happen? Where does an API gateway fit? Explain when you would choose a synchronous API call and when you would choose asynchronous messaging. Check that you describe the communication itself, not just name the services involved.
Can I explain data changes and dependency failures?
Check both how services handle data and how they respond when a dependency is slow or unavailable.
- Which service owns the database, and when would you use a Saga?
- Where would the outbox pattern fit in reliable event processing?
- How would you use timeouts, retries, and circuit breakers without overwhelming a downstream service?
- How would your design handle heavy load and outages?
Can I explain how I would test and run the services?
Go beyond the design. Can you explain how you would isolate a service for testing and deploy it? Can you trace a request across services using distributed tracing and correlation IDs? For security, can you describe service-to-service protection, where secrets are managed, and how tokens or certificates are rotated?
Who gets asked Microservices
The 20 most asked Microservices questions
Counted by interview, not by mention: a question asked twice in one conversation counts once.
How do you decide whether to use a monolith or move to microservices?
Asked in 20 of 131 interviews · last asked Oct 16 · Design · Senior
Show answer
I would start with a modular monolith unless there is a clear need for independent releases, scaling, or team ownership. Microservices make sense when those benefits outweigh harder operations, network failures, and data consistency work. I would split services around business functions, clear data ownership, and team responsibilities, then extract them gradually.
- A modular monolith keeps deployment simple while separating business functions in code.
- Use service boundaries based on business domains, data ownership, and team responsibilities, not scaling alone.
- Check whether the team can handle automated deployments, monitoring, and failures across services.
- Extract a service only when its benefits justify network calls and harder data coordination.
What the interviewer checks: The interviewer is checking whether you can justify the architecture and service boundaries using business needs and operational trade-offs.
Common mistake (in 4 of 13 reviewed answers): Many answers forget that scaling alone does not define service boundaries; consider business domains, data ownership, and team responsibilities.
Other ways it was asked
- “How would you decide how to split a monolith into microservices?”
- “When would you choose microservices over a monolith, and when would you not?”
- “When starting a project, how would you choose between a modular monolith and microservices?”
What are microservices, what benefits do they offer, and when would you use them?
Asked in 17 of 131 interviews · last asked Oct 7 · Concept · Mid-level
Show answer
Microservices split an application into small services, each focused on a business function and deployed independently. They communicate through APIs or messages. They let teams release and scale services separately. I would use them for a complex system with clear service boundaries and independent teams, when those benefits justify the extra operational work.
- Each service owns its business logic and data; other services use its interfaces.
- Independent deployment and scaling help teams work without coordinating every release.
- Network failures, data consistency, monitoring, and testing become harder.
- A monolith is often simpler for small teams or systems with unclear boundaries.
What the interviewer checks: The interviewer checks whether you understand service independence and can weigh its benefits against distributed system complexity.
Other ways it was asked
- “What are microservices?”
- “What are microservices, and when would you use them?”
- “What is a microservices architecture, and when would you use one?”
How do requests flow through a microservices application, and how do services communicate?
Asked in 12 of 131 interviews · last asked Oct 23 · Concept · Mid-level
Show answer
A client request often enters through an API gateway, which routes it to a service. That service may call other services using HTTP/REST or gRPC and wait for their responses. Services can also send messages through a broker for other services to process later. Use synchronous calls for immediate answers and asynchronous messaging for work that can finish later.
- An API gateway is common, but clients can also reach services directly.
- Synchronous calls need timeouts and failure handling because another service may be slow or unavailable.
- Asynchronous messaging reduces direct dependencies, but consumers must handle possible duplicate messages and delayed updates.
CodeClient -> API gateway -> Order service Order service -> Inventory service: HTTP request to check stock Inventory service -> Order service: stock response Order service -> Message broker: OrderCreated event Message broker -> Email service: send confirmation laterWhat the interviewer checks: The interviewer checks whether you can trace a request and choose between direct calls and asynchronous messages.
Common mistake (in 5 of 8 reviewed answers): Many answers forget that services need a concrete communication mechanism, such as HTTP/REST calls or messages sent through a broker.
Other ways it was asked
- “How do microservices communicate with each other?”
- “What are the ways microservices can communicate with each other?”
- “How do microservices communicate with each other? Can you give an example?”
How do you design and implement a microservice?
Asked in 8 of 131 interviews · last asked Sep 25 · Design · Mid-level
Show answer
I start with one clear business responsibility and define the service’s APIs, events, and data ownership. I implement the business logic, secure access, and test both behavior and service contracts. I add timeouts, safe retries, logs, metrics, and tracing. I automate deployment so the service can be released independently, then scale it based on measured demand.
- Choose boundaries around business needs, not technical layers; avoid services that constantly call each other.
- Let each service own its data; plan for consistency across services without relying on shared database tables.
- Handle network failures with timeouts and limited retries; make retried operations safe from duplicate effects.
- Use automated tests, compatible API changes, health checks, and rollback support for independent releases.
What the interviewer checks: The interviewer wants to see whether you can define a useful service boundary and build a reliable, independently deployable service.
Other ways it was asked
- “What are the key considerations when designing a microservices architecture?”
- “What are some key factors to consider when designing scalable microservices?”
- “How do you design and build microservices?”
What is the Saga pattern in microservices, and when would you use it?
Asked in 5 of 131 interviews · last asked Oct 16 · Concept · Senior
Show answer
The Saga pattern splits a business operation across services into local transactions. If a step fails, compensating actions undo the business effects of completed steps. Use it when an operation spans several services, a single database transaction is not practical, and temporary inconsistency is acceptable.
- Choreography: services react to events without a central coordinator.
- Orchestration: a central coordinator tells services which steps to run.
- Compensation is a business action, not a database rollback.
- Steps and compensating actions should handle retries safely.
CodeAn order service creates a pending order, then inventory reserves stock. Payment fails, so inventory releases the stock. The order service marks the order as cancelled.What the interviewer checks: The interviewer checks whether you understand cross-service transactions, failure recovery, and the trade-off of eventual consistency.
Other ways it was asked
- “What is the Saga design pattern in microservices, and when would you use it?”
- “What is the core idea behind the Saga pattern in microservices architecture?”
- “What is the saga pattern?”
When would you use synchronous API calls versus asynchronous messaging between microservices?
Asked in 4 of 131 interviews · last asked Oct 23 · Concept · Mid-level
Show answer
Use synchronous API calls when the caller needs a result before continuing. Use asynchronous messaging when work can happen later, or several services need to react to an event. Synchronous calls are simpler but make callers depend on another service being available. Messaging handles traffic spikes well, but adds delivery and consistency challenges.
- Set timeouts for synchronous calls, and handle failures without blocking callers indefinitely.
- Messaging buffers work during traffic spikes, but consumers may fall behind.
- Asynchronous flows often need eventual consistency, duplicate handling, and retries.
- Choose based on when the result is needed, not just API versus Kafka.
CodeSynchronous: Fetch the current product details before showing the product page. Asynchronous: Publish an OrderPlaced event so an email service can send a receipt.What the interviewer checks: The interviewer checks whether you can balance response needs, failure handling, and operational complexity.
Other ways it was asked
- “What is the difference between synchronous and asynchronous communication between services?”
- “How would you decide whether to use synchronous or asynchronous communication between services?”
- “What is the difference between synchronous and asynchronous services, and when would you use each?”
What is an API gateway, and where does it fit in a microservices architecture?
Asked in 4 of 131 interviews · last asked Oct 1 · Concept · Mid-level
Show answer
An API gateway is an entry point between clients and backend services. It routes requests to the right service and can handle shared tasks such as authentication and rate limiting. It hides service locations from clients. It is especially useful with microservices, but monoliths can use it too.
- Clients call the gateway instead of tracking each service’s address.
- Common tasks include routing, authentication, rate limiting, and request logging.
- A gateway adds a network hop and needs redundancy to avoid a single point of failure.
- Keep business logic in services, not in the gateway.
CodeClient → API gateway → Order service → Product serviceWhat the interviewer checks: The interviewer checks whether you understand where a gateway sits, what it handles, and its trade-offs.
Other ways it was asked
- “What problem does an API gateway solve?”
- “What is the role of an API gateway?”
- “Where does an API gateway fit, and is it more suitable for monolithic or microservice-based systems?”
What is a circuit breaker, how does it work, and when would you use it?
Asked in 4 of 131 interviews · last asked Oct 12 · Concept · Senior
Show answer
A circuit breaker temporarily stops calls to a service after repeated failures or slow responses. When closed, it allows calls; when open, it rejects them immediately. After a wait, it enters a half-open state and allows limited test calls before closing or opening again. Use it for remote calls to limit cascading failures and give failing services recovery time.
- Set failure thresholds and a wait time before testing recovery.
- Open circuits fail fast; callers can return an error or a suitable fallback.
- Combine it with timeouts; it does not replace them.
- Keep retries limited so they do not overload a failing service.
What the interviewer checks: The interviewer checks whether you understand the three states and how circuit breakers limit failures across services.
Other ways it was asked
- “What is a circuit breaker?”
- “How does the circuit breaker pattern work?”
- “Can you explain the circuit breaker pattern?”
How would you handle a slow or unavailable downstream service without causing cascading failures or overwhelming it?
Asked in 4 of 131 interviews · last asked Oct 16 · Scenario · Senior
Show answer
I set timeouts and limit concurrent calls so a slow dependency cannot use up all resources. A circuit breaker stops calls after repeated failures and allows a few recovery probes. I retry only safe, temporary failures, with capped retries, exponential backoff, and jitter. If recovery fails, I return a safe fallback or fail fast.
- Keep timeouts and retries within the caller’s overall deadline.
- Retry only when safe, such as idempotent operations; honor Retry-After when provided.
- Use separate connection or worker pools and bounded queues to isolate dependency failures.
- Use cached or partial results only when valid; otherwise return a clear error.
What the interviewer checks: The interviewer checks whether you can contain dependency failures and avoid making an overloaded service worse.
Other ways it was asked
- “How would you handle a dependency that responds slowly or returns errors when your service calls it?”
- “If a downstream service becomes slow, times out, or returns 503 errors, what can the calling service do to avoid overloading it and give it time to recover?”
- “How would you handle a microservice that depends on another service that is down?”
How would you design microservices to handle heavy loads and remain resilient to outages?
Asked in 3 of 131 interviews · last asked Aug 26 · Design · Senior
Show answer
I would use stateless services behind load balancers, with multiple instances and autoscaling to handle demand. Caches reduce repeated reads, and queues absorb bursts when work can wait. For resilience, I would spread instances across availability zones, set timeouts and circuit breakers, and isolate failures so one failing service does not bring down the system.
- Retry only temporary failures, with limits and backoff; use idempotency keys to prevent duplicate operations.
- Scale databases carefully with indexes, replication, and partitioning where needed; more service instances can overload databases.
- Bound queues and reject excess requests rather than letting overload exhaust resources.
- Track latency, errors, and saturation; test peak loads and failures, including database failover.
What the interviewer checks: The interviewer checks whether you can handle traffic growth and failures without creating new bottlenecks or cascading outages.
Other ways it was asked
- “How would you design a microservices architecture to handle heavy loads, and what technologies and mechanisms would you use?”
- “How have you designed scalable microservices for enterprise applications?”
- “How do you design microservices for scalability and resilience to outages?”
What drawbacks can make microservices more expensive and difficult to maintain than a monolith?
Asked in 2 of 131 interviews · last asked Jun 11 · Concept · Mid-level
Show answer
Microservices add network, deployment, and operational complexity compared with a monolith. Teams must handle slow or failed service calls, keep data consistent across services, and test changes across service boundaries. More infrastructure, monitoring, and release coordination can raise costs, especially for small teams or simple applications.
- Network calls add delays and partial failures that in-process calls avoid.
- Separate data stores make cross-service transactions and data consistency harder.
- Debugging often uses centralized logs and distributed tracing; testing needs coordination across services.
- Many deployments and shared infrastructure increase operational work and require more expertise.
What the interviewer checks: The interviewer is checking whether you can explain when microservices add more cost and complexity than value.
Other ways it was asked
- “What challenges can make microservices expensive and difficult to maintain?”
- “What could be a drawback of the microservice pattern compared with a monolithic pattern?”
What microservice design patterns would you use, and when?
Asked in 2 of 131 interviews · last asked Sep 8 · Concept · Senior
Show answer
I use an API gateway when clients need one entry point to several services. I use events when services can react asynchronously without an immediate reply. For transactions across services, I use a saga with compensating actions. I use circuit breakers to stop repeated calls to failing services.
- AWS API Gateway can route requests and handle authentication, but business logic should stay in services.
- SQS supports queued work; EventBridge routes events. Consumers should handle duplicate messages safely.
- Sagas undo completed steps through business actions, not database rollbacks. AWS Step Functions can coordinate them.
- Circuit breakers work with timeouts and limited retries to reduce cascading failures.
What the interviewer checks: The interviewer checks whether you choose patterns for specific needs and understand their failure handling and trade-offs.
Other ways it was asked
- “Which AWS services and microservices patterns would you use when designing a microservices application?”
How would you approach building or maintaining a microservice, and what challenges would you anticipate?
Asked in 2 of 131 interviews · last asked Sep 25 · Behavioral · Senior
Show answer
I would start by understanding the business goal, service boundaries, and existing dependencies. Then I would define the API and data ownership, add tests, and automate deployment with a rollback plan. I would monitor errors, latency, and logs in production. The main challenges are network failures, data consistency across services, and changes that break other services.
- Keep responsibilities focused, and avoid splitting services so much that every request needs many network calls.
- Use timeouts and limited retries; make repeated requests safe before retrying.
- Plan how data stays consistent across services, including when updates fail.
- Secure service access, test API compatibility, and trace requests across services.
What the interviewer checks: The interviewer is checking whether you can build and operate a service while handling failures and dependencies.
Other ways it was asked
- “Tell me about a specific challenge you faced in Java microservices development and how you solved it.”
- “Tell me about a microservice you built or maintained and the challenges you faced.”
How would you incrementally migrate a monolith using the strangler pattern and a reverse proxy?
Asked in 2 of 131 interviews · last asked Aug 26 · Design · Senior
Show answer
Put a reverse proxy in front of the monolith and initially route all requests to it. Move one feature at a time into a service, then route that feature’s requests to the service. Keep other requests going to the monolith. Monitor each change, keep a safe rollback path, and remove old code once the service is stable.
- Choose clear feature boundaries and preserve client-facing APIs.
- Plan data ownership and keep data consistent during the transition.
- Shift traffic gradually and compare errors, latency, and results.
- Routing back is safe only if the monolith can still handle the service’s data changes.
What the interviewer checks: The interviewer is checking whether you can split a system gradually without breaking clients or losing data.
Other ways it was asked
- “How can you incrementally move functionality into a microservice while continuing to use the existing monolith?”
- “How would you handle the strangler pattern and reverse proxy during migration?”
How would you make communication between microservices efficient and reliable?
Asked in 2 of 131 interviews · last asked Jun 19 · Design · Senior
Show answer
I reduce network calls, keep payloads small, and reuse connections. I use synchronous calls when an immediate response is needed, and durable messaging for work that can wait. I add timeouts, limited retries with backoff and jitter, and circuit breakers. I make retried operations safe to repeat and monitor latency and failures.
- Set timeouts within the request deadline; retry only temporary failures and operations safe to repeat.
- Circuit breakers stop repeated calls to failing services and help prevent cascading failures.
- Durable messaging needs acknowledgments, duplicate handling, and a plan for messages that repeatedly fail.
- Use metrics and distributed tracing to find slow calls; apply backpressure when consumers cannot keep up.
What the interviewer checks: The interviewer is checking whether you can balance speed, failure handling, and the trade-offs between synchronous and asynchronous communication.
Other ways it was asked
- “When you choose a microservices architecture for its scalability and modularity, how do you ensure communication between services remains efficient and reliable?”
- “How would you optimize communication between microservices to reduce latency and improve overall system performance?”
How would you call multiple microservices concurrently, wait for their responses, and efficiently combine the results?
Asked in 2 of 131 interviews · last asked Jul 27 · Design · Senior
Show answer
I would start independent service calls concurrently with asynchronous I/O, then await them together and combine the responses into one result. I would set timeouts and decide whether a failed call should fail the whole request or allow partial results. To improve performance, I would reuse connections, limit concurrency, and cache suitable data.
- Parallel calls usually take about as long as the slowest call, plus processing overhead.
- Only independent calls can run together; dependent calls must wait for required data.
- Use an overall deadline and cancel unfinished work when it is no longer needed.
- Combine results by stable IDs or named fields, not response arrival order.
What the interviewer checks: The interviewer checks whether you can reduce latency while handling failures, dependencies, and resource limits.
Other ways it was asked
- “When writing code to call several services concurrently and wait for their responses, what would you consider?”
- “How would you call three microservices, wait for their responses, aggregate the results, and improve performance?”
How do you manage cross-service transactions and keep data consistent across microservices?
Asked in 2 of 131 interviews · last asked Aug 11 · Design · Senior
Show answer
I use local transactions within each service and usually choose eventual consistency across services. A saga coordinates the steps and uses compensating actions when a step fails. A transactional outbox publishes committed changes reliably, while idempotent consumers handle duplicate messages. If a business rule needs immediate consistency, I try to keep it within one service’s transaction.
- A saga’s compensating actions undo business effects; they are not database rollbacks.
- Write data changes and outbox events in the same local transaction.
- Use safe retries, duplicate detection, and ordering checks where event order matters.
- Monitor stuck workflows and reconcile data to find and repair inconsistencies.
What the interviewer checks: The interviewer checks whether you can choose consistency boundaries and handle partial failures without assuming one shared transaction.
Other ways it was asked
- “How would you approach ensuring data consistency across multiple services?”
- “How would you handle cross-service transactions after a system is split into microservices? What consistency model would you choose, and what mechanisms would you use to keep data correct over time?”
How would you prevent duplicate event processing in a microservices system?
Asked in 2 of 131 interviews · last asked Jul 22 · Design · Senior
Show answer
I would use idempotent handlers and track processed event IDs. In one database transaction, I would record the ID and apply the business change, skipping changes if the ID already exists. I would acknowledge the event only after commit. This prevents duplicate database changes, not duplicate delivery.
- At-least-once delivery can produce duplicates, so retries must be safe.
- Use a unique constraint on consumer name and event ID to handle concurrent retries.
- For external API calls, use a stable idempotency key supported by the receiving system.
- Keep processed IDs long enough to cover possible retries and replays.
What the interviewer checks: The interviewer checks whether you can prevent repeated business effects despite retries, crashes, and concurrent delivery.
Other ways it was asked
- “In a distributed system with microservices, how do you prevent duplicate processing?”
- “Imagine you have a microservice that processes events asynchronously and need to ensure each event is handled exactly once, with no duplicates. How would you approach that design?”
How would you trace a request across microservices and identify where it fails?
Asked in 2 of 131 interviews · last asked Sep 22 · Scenario · Senior
Show answer
I would use distributed tracing to follow the request across services and find the failing step. Each service passes trace context to the next and records spans for calls and database work. I would inspect failed or slow spans, then use the trace ID to find related logs and confirm the cause.
- Pass trace context through HTTP headers and message metadata, including across service or domain boundaries.
- Record spans for incoming requests, outgoing calls, and database reads and writes.
- Include trace and span IDs in logs to connect errors to specific operations.
- Check downstream failures, timeouts, and retries; the service reporting the error may not be its source.
What the interviewer checks: The interviewer checks whether you can connect a request across services and use traces and logs to locate its failure.
Other ways it was asked
- “If a request starts in domain A, passes to domain B, and fails there, how would you trace it across domains and identify where the error occurred?”
- “How would you trace an end-to-end request through a microservices system, from the user's action through service calls and data reads and writes?”
What are the differences between monolithic systems, microservices, and REST APIs in a Java and Spring Boot backend?
Asked once · last asked Feb 6 · Concept · Senior
Show answer
A monolith packages and deploys backend features as one application. Microservices split features into separate services that can be deployed and scaled independently. REST is a style for designing APIs, not an alternative to either architecture; both can expose REST APIs. In Java, Spring Boot can build a monolith or individual microservices.
- Monoliths are usually simpler to develop, test, and operate.
- Microservices support independent releases but add network failures, monitoring needs, and data consistency challenges.
- REST APIs expose resources through a uniform interface, commonly using HTTP methods, with stateless requests.
- Microservices can communicate through REST APIs, messaging, or other protocols.
What the interviewer checks: The interviewer checks whether you separate application architecture from API design and understand the main trade-offs.
Microservices basics interview questions
Compare microservices with monoliths, SOA, and serverless, including their benefits, drawbacks, and when to use them. 6 questions.
Imagine you're working on a project where you need to choose between building a microservices architecture from scratch or leveraging serverless computing for a new application. How would you evaluate the decision, and what would you prioritize in making your choice?
Asked once · last asked Mar 25 · Design · Senior
How does the choice of backend architecture—microservices, a monolith, or SOA—affect how you plan and implement tasks?
Asked once · last asked Apr 15 · Concept · Mid-level
Microservices system design interview questions
Service design questions cover boundaries, responsibilities, technology choices, design patterns, and implementation with common frameworks. 22 questions.
How would you design microservices to handle 2.5 million requests while keeping a changing dataset up to date across services?
Asked once · last asked Aug 22 · Design · Senior
Other ways it was asked
- “How would you design microservices to handle 2.5 million requests?”
- “How would you design the software infrastructure for microservices that use a shared dataset and handle 2.5 million requests per second?”
- “How would you design the software infrastructure for microservices that process a shared dataset and handle 2.5 million requests per second?”
How would you design and implement a microservices architecture integrated with Kafka?
Asked once · last asked Sep 23 · Design · Senior
Other ways it was asked
- “What microservices architecture would you choose for a system integrated with Kafka?”
How would you divide an application into microservices?
Asked once · last asked Mar 9 · Design · Senior
If the order service and limit service are decoupled, how should the order service determine whether an order is within the customer's limit?
Asked once · last asked Mar 19 · Design · Senior
Walk through the end-to-end flow when a user creates an order, including how the order and limit services interact.
Asked once · last asked Mar 19 · Design · Senior
Which technologies and frameworks would you use to design and implement a backend microservices workflow?
Asked once · last asked Mar 19 · Design · Mid-level
What is the sidecar pattern?
Asked once · last asked Apr 10 · Concept · Mid-level
How would you design a FastAPI-based microservice platform?
Asked once · last asked May 27 · Design · Senior
Other ways it was asked
- “Can you describe a FastAPI-based microservice platform that you built or architected?”
If you need to design an order processing system using microservices, what would your design approach be?
Asked once · last asked Jul 25 · Design · Senior
How would you evaluate whether a new technology is a good fit for your microservices architecture?
Asked once · last asked Jul 31 · Scenario · Senior
How do you design and develop a scalable microservice using Spring Boot?
Asked once · last asked Aug 4 · Design · Senior
How do you decide whether a shared utility should be a separate package or service versus a module in a monolith, and what failure modes are you trying to avoid?
Asked once · last asked Aug 13 · Design · Senior
Show 7 more
How would you design a microservices-based system to manage test results and share reports for raw materials that are manufactured in-house or purchased?
Asked once · last asked Aug 20 · Design · Senior
How would you design an e-commerce system in .NET with microservices, and would you use synchronous HTTP calls or a message broker like Azure Service Bus? How would you guarantee reliability if one service fails?
Asked once · last asked Sep 1 · Design · Senior
How would you divide responsibilities among a gateway, career service, profile service, and opportunity service in a full-stack search system?
Asked once · last asked Sep 22 · Design · Senior
What responsibilities should a marketing microservice handle, how would you scale it, and what challenges might arise?
Asked once · last asked Sep 25 · Design · Senior
When you review a pull request that introduces a new service boundary, what specific things do you look for to prevent hidden coupling such as shared database tables, synchronous chatty calls, and leaked domain concepts?
Asked once · last asked Oct 24 · Scenario · Senior
What is Spring Cloud, and what is it used for in microservices?
Asked once · last asked Oct 12 · Concept · Mid-level
Other ways it was asked
- “What is Spring Cloud, and how is it used for load balancing and health checks in microservices?”
What are the layers of services and microservices?
Asked once · last asked Jun 15 · Concept · Mid-level
Monolith to microservices migration interview questions
Explore migration planning, service extraction, legacy integration, strangler patterns, and ways to reduce compatibility and performance risks. 11 questions.
Given a monolithic application that takes orders, checks inventory, and generates reports, what would be your first step in migrating it to microservices, and how would you proceed?
Asked once · last asked Jan 30 · Design · Senior
How would you integrate a synchronous legacy system into an asynchronous microservice?
Asked once · last asked Apr 2 · Design · Senior
When refactoring a monolith into microservices, what objective criterion indicates that a proposed service boundary could create a distributed transaction problem?
Asked once · last asked Jul 16 · Design · Senior
How can contract-change validation affect rollout speed and incident rates during a microservices migration?
Asked once · last asked Jul 31 · Concept · Mid-level
What strategies or tools would you use to reduce the risk of breaking existing behavior during a migration to microservices?
Asked once · last asked Jul 31 · Scenario · Senior
How would you ensure that a transition to microservices does not negatively affect system performance?
Asked once · last asked Jul 31 · Scenario · Senior
How would you speed up nightly pricing calculations in a logistics system and split a monolith into microservices?
Asked once · last asked Jul 31 · Design · Senior
Suppose you're given a monolith and a goal to move to microservices. What decision framework would you use to identify service boundaries and sequence the migration with minimal risk?
Asked once · last asked Aug 11 · Design · Senior
What does it indicate when new services read fields directly from a legacy database instead of going through an anti-corruption layer?
Asked once · last asked Oct 18 · Scenario · Senior
Other ways it was asked
- “What does it indicate when new services read legacy database fields directly instead of using a translation layer?”
When you need to break up a monolith into microservices, what criteria do you use to choose the first service to extract, and how do you minimize risk during the transition?
Asked once · last asked Oct 24 · Design · Senior
Microservices communication interview questions
These questions cover REST, gRPC, messaging, API gateways, service discovery, service meshes, GraphQL federation, and API contracts. 26 questions.
How can a payment service notify a delivery service that an order has been paid so delivery can begin?
Asked once · last asked Feb 22 · Scenario · Mid-level
How can a user microservice communicate with an authentication microservice?
Asked once · last asked May 22 · Design · Mid-level
How can microservices built with .NET Core expose functionality through REST APIs?
Asked once · last asked Jun 25 · Concept · Mid-level
How do you ensure that the TypeScript monorepo seamlessly integrates with Rust microservices?
Asked once · last asked Jul 20 · Design · Senior
You are defining a new high-performance gRPC microservice with large datasets and huge unary payloads. What strategies and best practices would you use for protobuf messages and RPC protocols?
Asked once · last asked Aug 5 · Design · Senior
What is a service mesh, and why do we need it?
Asked once · last asked Sep 4 · Concept · Mid-level
If product, customer, and order data are owned by separate microservices, how would you design a federated GraphQL architecture to expose them through a unified API while keeping service independence and performance?
Asked once · last asked Sep 17 · Design · Senior
How would you design service API contracts, handle versioning and backward compatibility, and prevent breaking changes?
Asked once · last asked Sep 22 · Design · Senior
Other ways it was asked
- “How did you design service API contracts, handle versioning and backward compatibility, and prevent breaking changes?”
For a search request, how would you trace the server-side path through edge or gateway services, and what communication patterns would the services use?
Asked once · last asked Sep 22 · Design · Senior
How do you configure and manage an API Gateway for a microservices application?
Asked once · last asked Sep 23 · Tooling · Senior
How does GraphQL federation divide and compose a schema across services?
Asked once · last asked Sep 29 · Concept · Senior
How would application components communicate in a monolithic architecture versus a microservices architecture?
Asked once · last asked Oct 9 · Design · Mid-level
Other ways it was asked
- “How did the application components communicate, and was the system a monolith or a set of microservices?”
Show 9 more
Is Eureka part of Spring's component scan, and how does service discovery work with Spring Boot?
Asked once · last asked Oct 12 · Concept · Mid-level
How can service discovery identify which services are healthy and available?
Asked once · last asked Oct 12 · Scenario · Mid-level
What is Spring Cloud LoadBalancer, and how does it support internal load balancing?
Asked once · last asked Oct 12 · Concept · Mid-level
How do you use RestTemplate for communication between Spring microservices?
Asked once · last asked Oct 12 · Tooling · Mid-level
How would you expose a microservice so that 10 to 15 different consumers can use it?
Asked once · last asked Oct 16 · Design · Mid-level
In a microservices system, how do you document and govern cross service API contracts so teams can evolve independently without breaking consumers?
Asked once · last asked Oct 24 · Design · Senior
What is a Feign client?
Asked once · last asked Jul 21 · Concept · Junior
Should an order service call the payment service's endpoint directly?
Asked once · last asked Oct 9 · Concept · Mid-level
What is service discovery?
Asked once · last asked Oct 12 · Concept · Mid-level
Microservices data consistency interview questions
Data questions focus on database ownership, persistence, distributed transactions, Sagas, outbox, CQRS, and reliable event processing. 20 questions.
How would you handle a data inconsistency where System A times out but System B successfully processes the request?
Asked once · last asked Jul 31 · Scenario · Mid-level
Other ways it was asked
- “How would you design a solution to resolve the inconsistency between System A and System B when a timeout occurs but the request is still processed?”
How should an order service handle a connection failure when publishing a message to Azure Service Bus?
Asked once · last asked Sep 4 · Scenario · Senior
If an order is created but the inventory update fails, how can you ensure consistency and cancel or roll back the order?
Asked once · last asked Jan 30 · Scenario · Senior
How should three microservices with separate databases communicate to retrieve and share data?
Asked once · last asked Jan 31 · Design · Senior
What factors might justify migrating a microservice to MongoDB?
Asked once · last asked Feb 23 · Scenario · Mid-level
What is JPA, and why can it be useful in microservices?
Asked once · last asked Mar 6 · Concept · Mid-level
What is the Outbox pattern, and what problem does it solve?
Asked once · last asked Apr 2 · Concept · Mid-level
How would you ensure an order-created event is not lost and is eventually processed if a service restarts after the customer has received confirmation?
Asked once · last asked Apr 13 · Design · Senior
What are some alternatives to distributed transactions?
Asked once · last asked Apr 13 · Concept · Senior
How does managing persistence differ between a monolithic architecture and a microservices architecture?
Asked once · last asked May 22 · Design · Senior
How would you keep an order service and a subscription service consistent when the order service publishes an order-created event?
Asked once · last asked Jul 23 · Scenario · Senior
In a workflow spanning multiple microservices, how do you avoid duplication, handle retries, and recover if something fails?
Asked once · last asked Jul 27 · Design · Senior
Show 5 more
Why would you use CQRS, and can it help when transitioning to microservices?
Asked once · last asked Aug 20 · Concept · Senior
What are the Saga and transactional outbox patterns, and how do they address consistency in distributed transactions?
Asked once · last asked Sep 10 · Concept · Senior
How would you ensure a payment is processed correctly when you need to update its status, credit tokens, and notify other services?
Asked once · last asked Sep 18 · Design · Senior
Can you explain more about the difference between choreography and orchestration in the saga pattern?
Asked once · last asked Oct 12 · Concept · Senior
What are alternatives to using an orchestrator in a distributed workflow?
Asked once · last asked Sep 18 · Concept · Senior
Microservices resilience and scalability interview questions
Work through dependency failures, timeouts, retries, circuit breakers, availability trade-offs, heavy loads, and performance improvements. 18 questions.
How should an order service handle incoming orders when a downstream service is unavailable?
Asked once · last asked Oct 9 · Scenario · Senior
Other ways it was asked
- “What should happen when the order service receives a request while the payment service is down?”
- “How should the order service operate when the payment service is down?”
- “What should happen when a customer places an order while a downstream microservice is down?”
If the inventory service is down for 30 minutes while orders continue arriving, how should the system handle this without losing business or making the main service stop responding?
Asked once · last asked Jan 30 · Scenario · Senior
How would you handle a third-party vendor's API becoming unavailable in a payment-card ordering system?
Asked once · last asked Mar 16 · Scenario · Senior
How should an order flow handle communication failures between the limit service and order service, or an unavailable order service?
Asked once · last asked Mar 19 · Scenario · Senior
If both the order service and limit service are unavailable, how should the system handle order processing, and what availability trade-offs does this create?
Asked once · last asked Mar 19 · Design · Senior
How should the order service handle a GET request to the limit service that times out or receives no response, and what should the order API communicate?
Asked once · last asked Mar 19 · Scenario · Senior
What is the difference between a retry and a circuit breaker?
Asked once · last asked Apr 10 · Concept · Mid-level
A production microservice is receiving more traffic than it can handle. What could you do to keep it stable and prevent it from restarting?
Asked once · last asked Apr 13 · Scenario · Senior
How would you address a scalability problem in a microservices system?
Asked once · last asked Jun 19 · Design · Senior
How do you manage service dependencies so the code only runs when required dependencies are available?
Asked once · last asked Jul 27 · Scenario · Senior
How do you use connection pooling for microservices connecting to an on-premises relational database?
Asked once · last asked Aug 30 · Concept · Senior
What is the best way to handle communication and failures between an order service and a payment service?
Asked once · last asked Oct 9 · Design · Senior
Show 3 more
How do you ensure a request that involves multiple microservices completes end to end, and what do you do if one service fails?
Asked once · last asked Oct 23 · Design · Senior
How should a payment-card system respond if its card service crashes?
Asked once · last asked Mar 16 · Scenario · Senior
What circuit breaker patterns do you know?
Asked once · last asked Sep 1 · Concept · Mid-level
Microservices security interview questions
Security questions cover authentication, authorization, gateway trust, service-to-service protection, secrets, and token or certificate rotation. 6 questions.
How would you manage authenticated users across Next.js and microservices so a chat system can identify who is messaging, and what is a token?
Asked once · last asked Jul 16 · Scenario · Mid-level
How would you choose an authentication mechanism for a microservices architecture?
Asked once · last asked Jul 31 · Scenario · Mid-level
In a microservices setup, how do you secure service-to-service REST calls? Which auth mechanism do you use, and how do you manage token or certificate rotation?
Asked once · last asked Sep 10 · Scenario · Senior
In a microservices setup, how would you design authorization so services don't blindly trust a gateway?
Asked once · last asked Sep 16 · Design · Senior
How would you handle authentication and authorization from the browser through a gateway to downstream services?
Asked once · last asked Sep 22 · Design · Senior
Other ways it was asked
- “How would you handle authentication and authorization end to end, from the browser through an edge service to downstream services, and what checks belong at each hop?”
- “How would you handle authentication and authorization from the browser through a gateway to downstream services, including JWTs, roles, and secrets?”
How do you manage secrets for application deployments and for microservices connecting to backend databases?
Asked once · last asked Sep 22 · Scenario · Senior
Other ways it was asked
- “How should microservices consume secrets for backend database connections?”
Microservices testing and deployment interview questions
Prepare to discuss local development, test isolation, automation, CI/CD, containers, Kubernetes, and cloud deployment. 16 questions.
How would you design and deploy two microservices from separate Azure Repos repositories to AKS, including the architecture, deployment steps, and tools?
Asked once · last asked Jan 31 · Design · Senior
If you are not using a microservices architecture, would you still use Kubernetes?
Asked once · last asked Feb 11 · Scenario · Mid-level
How would you handle the challenges of local testing in serverless and microservices architectures?
Asked once · last asked Mar 18 · Behavioral · Senior
Other ways it was asked
- “Local testing can be difficult in serverless and microservices architectures. How have you handled it?”
What challenges can arise when a 20-person team develops and releases microservices using AWS Lambda, DynamoDB for operational data, and Redshift for analytics?
Asked once · last asked Mar 18 · Design · Senior
How do you manage end-to-end testing when an application consists of many services that must be started or kept running?
Asked once · last asked Mar 19 · Scenario · Senior
Can you talk about how Docker and Kubernetes together contribute to the scalability and resilience of microservices architectures?
Asked once · last asked Mar 25 · Concept · Mid-level
How would you deploy a set of microservices in a customer environment?
Asked once · last asked Apr 18 · Scenario · Mid-level
If services A, B, and C depend on one another, what is needed to connect them, and how would you run them locally to debug code or implement user stories?
Asked once · last asked May 5 · Scenario · Mid-level
How would you use continuous integration and delivery to support the development of microservices?
Asked once · last asked May 22 · Scenario · Senior
How would you test a microservice without making real calls to the other services?
Asked once · last asked Jun 23 · Scenario · Mid-level
Other ways it was asked
- “How have you tested a microservice without making real calls to the other services?”
Which AWS services would you use to deploy a microservice?
Asked once · last asked Jul 30 · Tooling · Mid-level
How would you set up a pipeline so that a broken test in one microservice doesn't block the deployment of unrelated services in a monorepo?
Asked once · last asked Aug 4 · Design · Senior
Show 4 more
How would you design an automated testing framework for a microservices application?
Asked once · last asked Aug 17 · Design · Senior
Other ways it was asked
- “How would you build an automation strategy for a large microservices-based application with UI, API, and backend layers?”
- “How do you design an automation testing framework for a microservices-based application?”
How do you build Docker images, write Kubernetes manifests, and create deployment guides for a microservice?
Asked once · last asked Aug 31 · Tooling · Mid-level
How do you see the role of Docker evolving in modern software development, particularly with trends in microservices and cloud-native applications?
Asked once · last asked Mar 25 · Concept · Mid-level
How would you implement, run, and deploy microservices?
Asked once · last asked May 5 · Tooling · Mid-level
Other ways it was asked
- “Do you know how to implement, run, and deploy microservices?”
Microservices monitoring and troubleshooting interview questions
Monitoring and troubleshooting questions cover tracing, correlation IDs, production debugging, performance targets, service ownership, and maintenance. 16 questions.
What is distributed tracing, and when would you use it?
Asked once · last asked Mar 2 · Concept · Mid-level
How would you assess who should maintain a system split into 55 microservices?
Asked once · last asked Apr 17 · Scenario · Senior
If you were debugging the order-processing domain in production, how would you debug interactions with the other domains?
Asked once · last asked May 5 · Scenario · Senior
How would you pass a trace identifier through the producer, broker, and consumers so logs and metrics can be correlated across services?
Asked once · last asked May 23 · Design · Senior
How would you troubleshoot a communication problem between two microservices?
Asked once · last asked Jun 19 · Scenario · Mid-level
How do you decide when it's necessary to refactor a microservice rather than building a new one from scratch?
Asked once · last asked Jul 31 · Scenario · Senior
At 3 a.m., a microservice that normally responds in 300 milliseconds starts taking eight seconds, and there is no useful information in the logs. How would you investigate the root cause?
Asked once · last asked Jul 31 · Scenario · Senior
How would you implement distributed tracing and correlation IDs across multiple microservices?
Asked once · last asked Sep 2 · Design · Senior
If one microservice is slow and upstream services start failing, how would you diagnose and solve that microservices issue?
Asked once · last asked Sep 2 · Scenario · Senior
Your manager asks you to take ownership of a failing microservice that intermittently crashes in production. Walk me through how you would investigate logs, reproduce the issue, engage teammates, and track a fix through deployment.
Asked once · last asked Sep 23 · Scenario · Senior
When investigating a failing microservice, which teammates or areas of expertise would you involve, and how would you collaborate to validate your hypothesis?
Asked once · last asked Sep 23 · Scenario · Senior
What SLAs and nonfunctional requirements should be defined for a marketing microservice?
Asked once · last asked Sep 25 · Design · Senior
Show 3 more
What performance metrics would define "fast" for a marketing microservice, and how would you verify it meets those targets?
Asked once · last asked Sep 25 · Scenario · Senior
How would you design a distributed tracing and logging strategy across microservices so you can reliably debug a single user request end to end in production?
Asked once · last asked Oct 24 · Design · Senior
When you're documenting a complex microservice workflow for new on-call engineers, what sections do you include so they can diagnose incidents quickly without tribal knowledge?
Asked once · last asked Oct 24 · Scenario · Senior
Related interview questions
- Software Engineer interview questions
- DevOps Engineer interview questions
- Data Engineer interview questions
- AI Engineer interview questions
- Solutions Architect interview questions
- QA Engineer interview questions
- Cloud Engineer interview questions
- Data Structures and Algorithms interview questions
- OOP and Design Patterns interview questions
- System Design interview questions
- REST API interview questions
- Kafka and Message Queues interview questions
- Caching and Redis interview questions
- Operating Systems interview questions
- Computer Networks interview questions
- Git interview questions
How this list is made
Every question here was asked by a real interviewer in a real job interview that a candidate ran MeetAssist in. After the call, the interviewer's questions are pulled from the transcript. Practice sessions, tests, exams and anything that was not a job interview are dropped.
Questions are rewritten so they make sense on their own: names of people, employers and clients are removed, and speech-to-text mistakes are fixed. Small talk, logistics and questions about one candidate's own résumé are left out. Rephrasings of the same question are merged, and the count is the number of different interviews it came up in.
The interviews come from candidates who use MeetAssist, so they lean towards software, data and AI roles: the shares describe these interviews, not every Microservices interview. Answers to the most asked questions are written and checked by an editor; a "common mistake" is shown only when reviews of real answers in these interviews show it, with the count.
131 interviews, 88 candidates, Dec 2025 to Oct 2026. Updated every month with new interviews.
Or add the Chrome extension