Recruiter’s Questions

1\ how do you approach debugging a production issue? great response "i start by gathering relevant information—logs, error messages, and recent deployments that might be related i look for patterns in when the issue occurs and identify the affected components i try to reproduce the issue in a controlled environment if possible for critical issues, i focus on implementing a temporary fix to restore service while working on the root cause analysis once resolved, i document the incident, solution, and preventive measures, then create tickets for any technical debt identified during the process i also believe in conducting blameless post mortems to improve our systems and processes " mediocre response "i check the logs to see what's happening and try to find where the error is occurring then i make the necessary code changes to fix it if i can't figure it out myself, i ask another developer for help after fixing it, i make sure to test that it works " poor response "i usually look at the error logs and try to fix whatever is broken as quickly as possible if the issue is complex, i might roll back to a previous version so we can get the service running again most of the time, i focus on addressing the immediate problem rather than investigating deeper causes since uptime is our priority " 2\ describe your experience with api design great response "i follow rest principles when designing apis, focusing on resource oriented endpoints with clear naming conventions i carefully consider versioning strategies from the start to support backward compatibility for complex operations, i evaluate whether rpc style endpoints might be more appropriate documentation is critical—i use tools like openapi/swagger to maintain living documentation that evolves with the api i also build with error handling in mind, designing consistent error responses with appropriate status codes and messages performance considerations like pagination, filtering, and selecting specific fields are built in from the beginning rather than added later " mediocre response "i've built several rest apis using frameworks like express and django i follow standard practices like using nouns for resources and http methods for operations i use json for request and response bodies and implement proper status codes i make sure to document the endpoints so other developers know how to use them " poor response "i typically create endpoints based on whatever functionality the frontend needs i use post for most operations since it's the most flexible and allows me to send complex data structures as long as the api works and the frontend team can use it, i consider it successful i usually document everything after the api is built and stable " 3\ how do you ensure the security of your backend applications? great response "security is a multi layered approach in my development process i implement proper authentication using industry standards like oauth 2 0 and jwt, with careful attention to token management for authorization, i follow the principle of least privilege and implement role based access controls i validate all inputs on the server side regardless of client side validation and use parameterized queries to prevent sql injection i keep dependencies updated and regularly review security advisories i also believe in security testing—both automated tools like sast and manual penetration testing finally, i implement proper logging for security events to detect and respond to potential breaches " mediocre response "i make sure to use authentication and authorization in my applications i validate user inputs and escape any data before using it in database queries i keep libraries and frameworks updated to avoid known vulnerabilities and use https for all communications i try to follow security best practices recommended by the framework i'm using " poor response "i rely on our security team to handle most security concerns, but i do implement authentication using the built in features of our framework i trust that most frameworks have security built in, so as long as i'm following their patterns, things should be secure for specific security requirements, i usually wait for the security team's review and implement their recommendations when they provide them " 4\ describe how you handle database performance optimization great response "i approach database optimization methodically first, i identify performance bottlenecks through monitoring and profiling, looking at slow query logs and execution plans i optimize schema design with proper normalization balanced against query patterns, and implement appropriate indexing—being careful to add indexes that support common queries without over indexing i use database specific features like materialized views when appropriate for scaling, i implement strategies like read replicas, sharding, or partition tables based on access patterns i also look beyond the database itself—using caching strategies and optimizing application level data access patterns finally, i regularly review performance as data grows to catch issues before they impact users " mediocre response "i make sure to add indexes to columns that are frequently queried i try to write efficient sql queries and avoid n+1 query problems when a query is slow, i use the database's explain plan feature to understand what's happening and optimize accordingly i also use caching when appropriate to reduce database load " poor response "when we notice the database is running slowly, i add indexes to speed things up if queries are still slow, i usually look at using more powerful hardware for the database server i've found that most performance issues can be solved by vertical scaling—adding more cpu and memory usually fixes the problem without requiring complex changes to the code or database design " 5\ how do you approach writing maintainable code? great response "maintainable code starts with a clear architecture that separates concerns and follows solid principles i write self documenting code with meaningful variable and function names, and add comments to explain the 'why' rather than the 'what ' i keep functions small and focused on a single responsibility i use consistent coding standards, which i enforce with linters and formatters configured in the ci/cd pipeline i write comprehensive tests at different levels—unit, integration, and end to end—to catch regressions and document expected behavior i practice continuous refactoring to keep technical debt in check, and i believe in code reviews not just to catch bugs but to share knowledge and maintain consistent patterns across the codebase " mediocre response "i try to follow good naming conventions and organize code logically i add comments to explain complex parts of the code and write unit tests for important functionality i do my best to follow the existing patterns in the codebase to keep things consistent during code reviews, i look for potential issues and suggest improvements " poor response "i focus on getting features working correctly first, then clean up the code if there's time before the deadline i document complex sections with detailed comments so others can understand what's happening i try to follow the dry principle by creating utility functions for repeated code as long as the code works correctly and passes our tests, i consider it maintainable enough for our needs " 6\ tell me about a time you had to make a technical decision with limited information great response "we needed to select a message queue system for a new distributed architecture with tight deadlines i had incomplete requirements and limited time to research options i approached this by first defining our must have criteria reliability, throughput requirements, and integration with our existing systems i quickly researched the top 3 options that met these core needs, created a decision matrix with the known factors, and identified key unknowns for these unknowns, i created small proof of concepts to test critical assumptions based on this targeted approach, we selected kafka for its scalability and durability guarantees i also documented our decision process, assumptions, and areas to re evaluate as we learned more this approach delivered a timely decision while acknowledging the limitations of our knowledge " mediocre response "we had to choose between sql and nosql databases for a new project with a tight timeline i looked at the requirements we had and researched both options online based on my understanding that we needed complex queries and data consistency, i recommended going with postgresql the decision worked out well for the project, though we did have some scaling challenges later that we managed to overcome " poor response "we needed to pick a framework for a new service but didn't have much time to decide i'd had good experiences with django in previous projects, so i recommended we use it since i knew it could handle most requirements we might have i figured it was better to go with something familiar that i could implement quickly rather than spending too much time evaluating options the project was delivered on time, which was the main priority " 7\ how do you handle technical disagreements with team members? great response "i approach technical disagreements as opportunities for better solutions and team growth first, i make sure i fully understand their perspective by asking clarifying questions and restating their points i focus on objective criteria like performance metrics, maintainability, and alignment with business goals rather than personal preferences when presenting my view, i explain my reasoning and supporting evidence, using concrete examples where possible if we're at an impasse, i suggest time boxed experiments or prototypes to test different approaches sometimes, i'll propose a hybrid solution that addresses the core concerns of both sides throughout the process, i remain open to changing my mind when presented with compelling evidence the goal isn't to 'win' but to find the best solution for the product and team " mediocre response "i try to have a constructive conversation about the pros and cons of each approach i present my reasoning and listen to theirs if we can't agree, i'm willing to compromise or defer to the team lead to make the final decision i think it's important to respect others' opinions even if i disagree with them " poor response "i explain my solution and the technical reasons why i think it's the best approach if they still disagree, i usually suggest we go with the simpler solution that we can implement faster, since that lets us meet our deadlines if there's still disagreement, i'll typically defer to whoever has more experience with the particular technology we're discussing to make the final call " 8\ how do you approach learning new technologies or frameworks? great response "i follow a structured approach to learning new technologies i start with official documentation to understand core concepts and design philosophy then i build a small but non trivial project that exercises different aspects of the technology, deliberately pushing beyond basic examples i connect with the community through forums, github discussions, or meetups to learn best practices and common pitfalls i also compare it with technologies i already know to identify conceptual similarities and differences for deeper understanding, i explore the source code or underlying implementations when relevant i keep a learning journal to document insights and questions, which helps identify gaps in my understanding finally, i try to explain what i've learned to colleagues, as teaching reinforces learning and exposes areas i need to study further " mediocre response "i usually start with online tutorials and documentation to get the basics down then i work on small practice projects to get hands on experience if i run into problems, i search for solutions online or ask questions on stack overflow i try to allocate regular time for learning and practicing with the new technology until i feel comfortable using it in production " poor response "i learn best by diving in and solving real problems when we need to use a new technology, i'll look up examples online that are similar to what we need and adapt them to our requirements i find that focusing on just the parts we need to use is more efficient than trying to learn everything about a framework if i get stuck, i can always find solutions on stack overflow or ask more experienced team members for help " 9\ describe your experience with microservices architecture great response "i've designed and implemented microservices architectures for three years, focusing on clear service boundaries defined by business capabilities i've learned that effective service communication is critical—i implement both synchronous (rest, grpc) and asynchronous (event driven) patterns depending on the use case i use api gateways for client facing services to handle cross cutting concerns for resilience, i implement circuit breakers, retries, and timeouts to prevent cascading failures observability is essential in distributed systems—i set up comprehensive logging, metrics, and distributed tracing i've also experienced the operational challenges of microservices, implementing ci/cd pipelines for independent deployment and containerization with orchestration tools like kubernetes from these experiences, i've learned that microservices aren't always the right choice—the complexity trade off only makes sense at certain scales and organizational structures " mediocre response "i've worked on projects where we broke down a monolithic application into microservices we created separate services for different business functions and had them communicate via rest apis i used docker for containerization and helped set up the ci/cd pipelines for deploying the services it made our application more scalable and allowed teams to work independently on different services " poor response "i worked on a project where we split our application into smaller services each service had its own database and api it was definitely more complex than a monolithic application, but it allowed us to deploy changes more quickly we sometimes had issues with services being unavailable or communication breaking down, but we usually resolved those by adding more error handling i mainly focused on developing the services i was assigned to rather than the overall architecture " 10\ how do you balance technical debt against delivering features? great response "i view technical debt management as an ongoing investment decision rather than an all or nothing choice first, i categorize technical debt based on its impact—some debt creates daily friction and compounds quickly, while other debt is contained and stable for high impact debt, i advocate for dedicated time in each sprint for targeted refactoring for lower impact debt, i apply the 'boy scout rule' of leaving code better than i found it when working in that area when planning new features, i identify opportunities to refactor related areas as part of the implementation i communicate technical debt to stakeholders in business terms—explaining how it affects development velocity, reliability, and security rather than using technical jargon this helps build support for necessary maintenance work finally, i maintain a technical debt inventory that we regularly review, so we can make informed decisions about what to address and when " mediocre response "i try to strike a balance by advocating for regular refactoring time in our sprints when implementing new features, i identify related technical debt that should be addressed at the same time i communicate to product managers when technical debt is slowing us down or increasing risk, so they understand why we need to allocate time to address it for critical deadlines, i might accept creating some technical debt if it's well documented and we plan to address it soon " poor response "i focus primarily on delivering the features that the business needs by their deadlines once we've met our commitments to stakeholders, i'll propose setting aside time to address technical debt i document shortcuts we've taken so we can come back to them later in my experience, it's usually more important to get features to market quickly than to have perfectly clean code, so i prioritize meeting deadlines and addressing technical debt when there's less time pressure " 11\ how do you ensure code quality in your projects? great response "i believe in a multi layered approach to code quality it starts with clear architectural patterns and coding standards that the team agrees on i implement automated checks through a combination of static analysis tools, linters, and formatters that run in the ci/cd pipeline and as pre commit hooks testing is crucial—i write comprehensive unit tests focusing on edge cases, integration tests for component interactions, and end to end tests for critical user flows code reviews are equally important for both technical correctness and knowledge sharing—i follow a checklist covering security, performance, maintainability, and business requirements i also believe in pair programming for complex features for continuous improvement, i track quality metrics like test coverage, static analysis results, and defect rates, using them to identify areas for improvement finally, i conduct regular refactoring sessions and architecture reviews to prevent quality degradation over time " mediocre response "i write unit tests for my code and participate in code reviews to catch issues before they reach production i use linters and static analysis tools to identify potential problems automatically when bugs are found, i make sure to write regression tests to prevent similar issues in the future i try to follow clean code principles and keep methods small and focused on a single responsibility " poor response "i rely mostly on our qa team to identify issues in my code i do manual testing of my changes to make sure they work as expected, and i write some unit tests for complex logic i follow the existing patterns in the codebase to maintain consistency when there are bugs, i fix them quickly and try to learn from the mistakes to avoid similar issues in the future " 12\ describe a challenging backend problem you solved recently great response "we were experiencing intermittent performance degradation in our payment processing service that was difficult to reproduce i approached this methodically by first implementing enhanced logging and metrics to gather more data the patterns revealed that slowdowns correlated with specific types of transactions and increasing system load i created a test environment that simulated high concurrency and identified a connection pool issue where we were creating new database connections instead of reusing existing ones this led to connection thrashing under load i implemented a proper connection pooling configuration with appropriate sizing based on our workload patterns and added monitoring for pool usage i also discovered that certain queries weren't using indexes effectively during these high load periods, so i optimized them with more efficient indexes and query structures after deploying these changes, our 99th percentile response time improved by 70%, and we eliminated the intermittent slowdowns entirely i documented the investigation process and solution for the team, along with new monitoring alerts to catch similar issues earlier " mediocre response "we had an api endpoint that was timing out for users with large amounts of data i investigated the issue and found that we were loading too much data in memory i implemented pagination for the database queries and modified the api to return data in smaller chunks this fixed the timeout issues and improved the overall performance of the endpoint i also added some caching to further improve response times " poor response "one of our services was throwing errors randomly in production i added more detailed logging to track down the issue and found that it was related to a third party api we were using their service would occasionally time out, causing our application to crash i added error handling and retry logic to work around the issue it was a quick fix that solved the immediate problem without requiring major changes to our code " 13\ how do you approach optimization in your backend applications? great response "i follow a data driven approach to optimization i start by establishing baseline performance metrics and defining clear goals rather than optimizing prematurely, i use profiling tools and monitoring to identify actual bottlenecks once i've identified specific issues, i prioritize them based on impact and effort required i implement optimizations incrementally, measuring the impact of each change to ensure it's effective database optimization is often critical—i analyze query patterns, add appropriate indexes, and optimize query structure for application code, i look for inefficient algorithms, unnecessary computations, or memory issues caching strategies at various levels—database query results, api responses, or computed values—can dramatically improve performance for read heavy operations i also consider architectural optimizations like asynchronous processing for non critical operations throughout this process, i maintain a balance between optimization and code readability, documenting performance critical code thoroughly " mediocre response "when i notice performance issues, i use profiling tools to identify the slowest parts of the application i focus on optimizing database queries first, since they're often the bottleneck i'll add indexes where needed and rewrite inefficient queries for application code, i look for loops or algorithms that could be more efficient i implement caching for frequently accessed data that doesn't change often i test before and after my changes to make sure they actually improve performance " poor response "i typically wait until we have performance issues before spending time on optimization when users report slowness, i'll look at what they were doing and try to speed up that specific operation usually, adding indexes to the database solves most performance problems if that doesn't work, i might implement some caching or look for obvious inefficiencies in the code i find that upgrading to more powerful servers is often the quickest solution for performance issues " 14\ how do you handle version control and branching strategies? great response "i prefer a git flow or trunk based development approach, depending on the team and project needs for more structured teams, i use a modified git flow with feature branches created from develop, followed by pull requests with automated checks and code reviews for smaller teams or more experienced developers, i lean toward trunk based development with short lived feature branches and frequent integration to main i emphasize small, focused commits with descriptive messages that explain the why, not just the what for release management, i use semantic versioning and maintain change logs i believe in automating as much as possible—using hooks for linting and testing, and ci/cd pipelines for validation i also implement branch protection rules to prevent force pushes to important branches and require review approvals for complex features, i use feature flags rather than long lived branches to manage incomplete or experimental code in production " mediocre response "i use git for version control and typically follow a branching strategy where we have a main branch for production code and develop branches for ongoing development i create feature branches for new work and submit pull requests when complete i try to make regular commits with clear messages describing what changed we use code reviews before merging to ensure quality for releases, we create release branches and tag versions appropriately " poor response "i follow whatever branching strategy my team has established usually, i create a branch for each task i'm working on, then merge it back when i'm done i commit my changes when i reach a good stopping point, typically at the end of the day or when a feature is complete for merge conflicts, i usually take the most recent changes unless i know there's a specific reason not to version control is mainly a way to back up code and collaborate, so as long as everyone can access the latest code, the specific process isn't that important to me " 15\ describe your experience with scaling backend systems great response "i've scaled systems from thousands to millions of users by applying both horizontal and vertical scaling strategies for horizontal scaling, i design stateless services that can be easily replicated behind load balancers, using consistent hashing for routing when needed database scaling is often the most challenging—i've implemented read replicas for read heavy workloads, sharding for write heavy systems, and cqrs patterns to separate read and write models caching is crucial at multiple levels in memory caches like redis for hot data, cdn caching for static assets, and application level caching for computed results i've also implemented asynchronous processing with message queues for non critical operations to handle traffic spikes gracefully beyond technical solutions, i focus on performance budgets and regular load testing to catch scaling issues before they impact users monitoring and observability are essential—i set up comprehensive metrics, alerts, and dashboards to track system health and identify bottlenecks proactively " mediocre response "i've worked on systems that needed to handle increasing load i've implemented horizontal scaling by deploying multiple instances of our services behind load balancers for database scaling, i've used read replicas to offload read traffic from the primary database i've also implemented caching using redis to reduce database load for frequently accessed data when we experienced performance issues, i helped identify bottlenecks and optimize code and queries to handle higher throughput " poor response "when our application started experiencing performance issues due to increased traffic, we initially upgraded our server resources to handle the load we added more cpu and memory to our database server and application servers when that wasn't enough, we split our monolithic application into a few services and deployed multiple instances of each we also added some caching to reduce database load this approach let us scale up quickly without having to make major architectural changes " 16\ how do you approach writing documentation for your code and systems? great response "i view documentation as an integral part of the development process, not an afterthought i follow a layered approach code level documentation through clear naming and targeted comments explaining the why (not the what); api documentation using standards like openapi/swagger that's generated from code when possible; and system level documentation covering architecture decisions, data flows, and integration points i prefer living documentation that's close to the code—in repositories, readmes, and wikis linked from the code—and automated when possible to prevent drift for architectural decisions, i use lightweight adrs (architecture decision records) to document the context and rationale behind significant choices i also create onboarding guides focusing on the developer experience, with clear setup instructions and common workflows i regularly review and update documentation during sprint retrospectives, treating documentation issues as seriously as code issues " mediocre response "i document my code with comments explaining complex logic and add docstrings to functions and classes describing their purpose and parameters for apis, i create documentation showing the endpoints, request parameters, and response formats i try to keep a project readme updated with setup instructions and basic usage examples when making significant architectural changes, i update our documentation to reflect the new structure " poor response "i focus on writing self documenting code with clear variable and function names so that the code itself serves as documentation for complex logic, i add comments explaining what's happening if the team requires formal documentation, i'll create it after the code is stable, usually documenting the api endpoints and how to use them i find that detailed documentation often gets outdated quickly, so i prefer to keep it minimal and focus on the most important aspects of the system " 17\ how do you handle cross team collaboration on backend projects? great response "effective cross team collaboration starts with clear interfaces and expectations i begin by establishing well documented apis with versioning strategies and backward compatibility guarantees i create comprehensive api documentation that includes examples, error scenarios, and rate limits for more complex integrations, i develop integration test environments and shared test cases that both teams can use to validate their implementations i believe in proactive communication—scheduling regular sync meetings during critical integration phases and using shared channels for async questions i've found that embedding team members temporarily across teams during major integrations helps build empathy and catch misunderstandings early for dependencies between teams, i use clear, documented contracts and slas for both functional and non functional requirements when conflicts arise, i focus on the broader business goals and user needs rather than team specific priorities i also advocate for blameless postmortems after major integrations to continuously improve our cross team processes " mediocre response "i try to establish clear communication channels with other teams we work with when our systems need to integrate, i document the api interfaces clearly and share them early to get feedback i participate in cross team meetings to discuss requirements and implementation details if there are dependencies, i make sure they're tracked and communicate status updates regularly when issues arise, i work directly with the relevant team members to find solutions quickly " poor response "i focus on clearly defining the apis or interfaces between our systems so other teams know what to expect i document what they need to know about our services and ask them to do the same when we have dependencies, i follow up regularly to make sure they're on track if there are delays or issues from other teams, i escalate to project managers or team leads to help resolve them i find it's most efficient when each team can work independently as much as possible " 18\ describe how you stay updated with backend development trends and best practices great response "i maintain a multi faceted approach to staying current i follow a curated list of industry leaders and engineering blogs from companies solving similar problems at scale i allocate time weekly to read technical papers and articles, focusing on depth over breadth i participate in open source projects related to our stack to understand evolving best practices and implementation patterns for hands on learning, i experiment with new technologies through personal projects or internal proof of concepts i'm active in several developer communities, both online forums and local meetups, where i can discuss practical applications of new approaches i also believe in knowledge sharing—i present findings to my team through brown bag sessions and maintain an internal tech radar for tracking relevant technologies rather than chasing every trend, i evaluate new approaches against our specific problems and constraints, looking for proven patterns that solve real issues we're facing " mediocre response "i subscribe to several tech newsletters and follow backend development blogs i attend webinars and conferences when possible to learn about new technologies and approaches i also join online communities like stack overflow and reddit programming communities to see what others are discussing occasionally, i'll work on side projects to try out new frameworks or tools at work, i participate in knowledge sharing sessions where team members present on new technologies or techniques they've learned " poor response "i mainly learn about new technologies when we need them for our projects i'll search for information and tutorials online when i need to implement something new i occasionally check tech news websites to see what's trending if there's a specific technology we're considering adopting, i'll research it more thoroughly i find that focusing on the technologies we're actively using is more practical than trying to keep up with everything that's happening in the industry " 19\ how do you balance between delivering quickly and maintaining high quality code? great response "i see speed and quality as complementary rather than opposing forces i start by establishing automated quality guardrails—comprehensive test suites, linters, and ci/cd pipelines—that catch issues early without manual intervention i practice incremental development with frequent small releases rather than large, risky deployments for features with tight deadlines, i identify the minimal viable implementation that meets core requirements while maintaining our quality standards when we need to make trade offs, i communicate clearly with stakeholders about the options and implications, focusing on business impact rather than technical purity i distinguish between different types of technical shortcuts—some create compounding technical debt that slows future development, while others are contained and can be addressed later for the former, i push back more strongly i also schedule regular refactoring time to prevent quality deterioration finally, i believe that practices like tdd and pair programming often increase quality while ultimately improving delivery speed by catching issues earlier " mediocre response "i try to build quality in from the start by writing tests and following good design principles this actually saves time in the long run by preventing bugs and rework for features with tight deadlines, i focus on the core requirements first and make sure they're implemented well, then add nice to have features if time permits i communicate with stakeholders when quality might be compromised by rushing, so we can make informed decisions about trade offs " poor response "i prioritize meeting deadlines since that's what the business cares about most i implement the required features first and make sure they work correctly if time allows, i go back and clean up the code, add more tests, or improve the design when we're under time pressure, i document the shortcuts we take so we can address them later i've found that it's better to deliver working features on time, even if the code isn't perfect, than to miss deadlines while trying to make everything perfect " 20\ how do you handle mentoring junior developers on your team? great response "i approach mentoring as a personalized growth partnership i start by understanding their current skills, learning style, and career goals through one on one conversations for technical growth, i use a progressive approach—starting with pair programming sessions where i model thinking processes, then assigning increasingly complex tasks with appropriate guardrails code reviews become teaching opportunities—i provide specific, actionable feedback with explanations and references to learn more beyond coding, i help develop their system design skills through whiteboarding sessions and architectural reviews i balance challenge and support by pushing them beyond their comfort zone while ensuring they don't get completely stuck i also focus on meta skills like debugging approaches, reading documentation effectively, and asking good questions i celebrate their successes publicly while handling improvement areas privately most importantly, i create psychological safety by normalizing mistakes as learning opportunities and sharing my own learning journey and challenges " mediocre response "i try to be available for questions and provide guidance when junior developers get stuck during code reviews, i explain the reasoning behind my suggestions so they understand the principles, not just the specific changes i assign tasks that stretch their abilities but aren't overwhelming, and check in regularly on their progress i share useful resources and articles that have helped me i also try to include them in design discussions so they can learn how we approach problems " poor response "i provide detailed specifications for tasks assigned to junior developers so they know exactly what to implement when they have questions, i point them to documentation or examples in our codebase that they can follow during code reviews, i make sure their code meets our standards and suggest corrections when needed i find that most junior developers learn best by working on real tasks and figuring things out on their own, with guidance when they really need it "