Questions 1–200 of 267
What is eventual consistency?
Asked in 4 of 942 interviews · last asked Oct 15 · Concept · Mid-level
Show answer
Eventual consistency means copies of data can temporarily disagree, but will converge if updates stop and changes can reach every copy. Users may see old data or different results from different servers. Tests should allow for this delay and check that results become consistent, rather than expect every read to show the latest write.
- It does not guarantee that a read immediately shows the latest write.
- Convergence depends on updates reaching replicas and conflicts being resolved.
- Users may notice delayed profile changes, search updates, or like counts.
- Tests can retry reads within a timeout based on the system’s requirements.
What the interviewer checks: The interviewer is checking whether you understand delayed consistency and its effects on users and tests.
Other ways it was asked
- “What is eventual consistency, and what implications does it have for testing?”
- “What is eventual consistency, and where might users notice it?”
What is database replication?
Asked in 2 of 942 interviews · last asked Feb 22 · Concept · Junior
Other ways it was asked
- “What is database replication, and what is it used for?”
- “How does database replication work, and what is it used for?”
- “How does database replication work?”
How do you design and implement batch processing?
Asked in 2 of 942 interviews · last asked Jun 10 · Concept · Mid-level
Other ways it was asked
- “What do you consider when designing and developing batch processing systems?”
How does the Raft consensus algorithm work, and how would you use it?
Asked in 2 of 942 interviews · last asked Aug 21 · Concept · Senior
Other ways it was asked
- “What is the Raft consensus algorithm, and how does it work?”
What are distributed transactions, and when would you use them?
Asked in 2 of 942 interviews · last asked Aug 19 · Concept · Mid-level
Other ways it was asked
- “What are some alternatives to distributed transactions?”
What is sharding?
Asked in 2 of 942 interviews · last asked Mar 27 · Concept · Junior
Other ways it was asked
- “What is database sharding?”
How does data replication work in the cloud?
Asked in 2 of 942 interviews · last asked Dec 4 · Concept · Mid-level
Other ways it was asked
- “What are the types of data replication in cloud computing?”
What architecture and tools would you use in an SAP Datasphere project?
Asked in 2 of 942 interviews · last asked Oct 6 · Design · Senior
Other ways it was asked
- “How do you consume data in SAP Datasphere, and what does the architecture look like?”
How would you balance user experience against consistency in a payment-card system?
Asked once · last asked Mar 16 · Scenario · Senior
Other ways it was asked
- “How would you handle a conflict between a consistency requirement and a better user experience in a payment-card system?”
When writing data that must appear in both a cache and a database, which should receive the initial write?
Asked once · last asked Mar 16 · Design · Senior
Other ways it was asked
- “When writing data to both a cache and a database, which should receive the initial write?”
How would you handle atomicity when updating both a cache and a database?
Asked once · last asked Mar 16 · Design · Senior
Other ways it was asked
- “How can you make an operation that updates both a cache and a database atomic?”
For a system like Instagram, would you choose a NoSQL or relational database? Give specific examples and explain why.
Asked once · last asked May 11 · Design · Senior
Other ways it was asked
- “If you chose a NoSQL database for a system like Instagram, which one would you select, such as MongoDB, and why?”
How would you approach designing an end-to-end system for handling high-volume real-time event data like user actions or messages coming in rapidly?
Asked once · last asked Jul 22 · Design · Senior
Other ways it was asked
- “How would you approach end-to-end system design for handling high volume of basic event data like user actions or messages coming in rapidly? Walk through the key components you'd consider.”
- “How would you architect a system that needs to handle a high volume of real-time events to ensure scalability and reliability?”
How could you generalize an application-level cache for use across multiple APIs or endpoints?
Asked once · last asked Jul 27 · Design · Senior
What novel approaches would you consider when building a data enrichment platform?
Asked once · last asked Aug 6 · Behavioral · Senior
Other ways it was asked
- “What novel approaches did you use to build a data enrichment platform?”
How would you design a simplified real-time data processing architecture using AWS services and Kafka Streams?
Asked once · last asked Sep 17 · Design · Senior
Other ways it was asked
- “What are the main components of a real-time data processing architecture using AWS and Kafka Streams, and how do they interact?”
How would you design a caching strategy, including how you would use Redis?
Asked once · last asked Sep 22 · Scenario · Senior
Other ways it was asked
- “How would you design a caching strategy with Redis?”
Where should business logic be applied in a file-ingestion pipeline that loads data into multiple database tables?
Asked once · last asked Oct 7 · Design · Senior
Should a source identifier be stored on each calculation event or on a higher-level object?
Asked once · last asked Oct 9 · Concept · Mid-level
Other ways it was asked
- “Should a source identifier be stored on each calculation event or on a higher-level object to avoid repeating it across object blocks?”
How would you design a stock-on-hand (SOH) and available-to-promise (ATP) status model and audit logs for inventory reservations?
Asked once · last asked Oct 17 · Design · Senior
Other ways it was asked
- “How would you design a stock-on-hand (SOH) and available-to-promise (ATP) status model and audit logs for reservations, picks, packing, shipping, cancellations, and returns across POS, OMS, and WMS?”
For an application storing videos and JSON-based metadata, why might PostgreSQL not be the best choice?
Asked once · last asked Oct 19 · Concept · Senior
How would you keep cached data up to date across multiple application instances when one instance changes it?
Asked once · last asked Jan 28 · Scenario · Senior
What is event sourcing, and how could it help with concurrent updates and notifying other users?
Asked once · last asked Jan 28 · Concept · 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
What is the difference between sharding and partitioning?
Asked once · last asked Feb 4 · Concept · Mid-level
What is the best practice when a system contains both dynamic data and data that does not change?
Asked once · last asked Feb 5 · Concept · Mid-level
Does a failover cluster instance (FCI) provide high availability using shared storage, or is there something else involved?
Asked once · last asked Feb 7 · Concept · Mid-level
Other ways it was asked
- “Does an FCI provide high availability using shared storage, or is there something else involved?”
When might you need a read replica in addition to shared storage in a failover cluster?
Asked once · last asked Feb 7 · Concept · Senior
For five nines of availability, would you choose Always On Availability Groups or a failover cluster instance, and why?
Asked once · last asked Feb 7 · Scenario · Senior
Is a Kafka cluster with two ZooKeeper nodes and four brokers an optimal setup, and what cost considerations would you evaluate?
Asked once · last asked Feb 18 · Scenario · Senior
What challenges, particularly with data, would you face when scaling up an existing Kafka cluster?
Asked once · last asked Feb 18 · Scenario · Senior
How would you scale a Kafka cluster by adding ZooKeeper nodes or brokers, and how would you decide how many to add?
Asked once · last asked Feb 18 · Scenario · Senior
What do you know about database replication and sharding?
Asked once · last asked Feb 22 · Concept · Mid-level
What factors should guide the choice of a database for a service?
Asked once · last asked Feb 23 · Scenario · Mid-level
Which database would you choose for a chat service that stores messages, photos, and other attachments: Redis, MongoDB, or PostgreSQL?
Asked once · last asked Feb 23 · Design · Mid-level
Why might MongoDB alone be insufficient for a chat service that stores messages, photos, and other attachments?
Asked once · last asked Feb 23 · Scenario · Mid-level
How do you usually approach high availability and disaster recovery for the databases you're responsible for?
Asked once · last asked Feb 24 · Scenario · Senior
How do you ensure data integrity across large distributed data systems or multiple databases, and what do you put in place to keep data accurate and consistent end to end?
Asked once · last asked Feb 24 · Scenario · Senior
How would you handle data from different sources or regions, and how would you orchestrate that processing?
Asked once · last asked Mar 3 · Scenario · Senior
How would you deploy and operate data pipelines beyond the notebook stage, and what infrastructure would you use?
Asked once · last asked Mar 7 · Design · Mid-level
How would you design indexing, partitioning, and scaling strategies—such as elastic pools, read replicas, or sharding—to ensure low-latency queries and high throughput for a massive influx of invoice records while maintaining relational integrity?
Asked once · last asked Mar 9 · Design · Senior
In a payment-card ordering and activation system, what does prioritizing consistency over availability mean?
Asked once · last asked Mar 16 · Concept · Senior
How would you choose a cache and database for a payment-card ordering system?
Asked once · last asked Mar 16 · Design · Senior
Why might you use Redis INCR to generate IDs instead of relying on a database primary key?
Asked once · last asked Mar 19 · Concept · Mid-level
If each £400 order passes an individual check against a £1,000 limit, can five orders exceed the limit, and why?
Asked once · last asked Mar 19 · Scenario · Senior
How would you prevent multiple orders from exceeding a customer's £1,000 limit?
Asked once · last asked Mar 19 · Scenario · Senior
How would you account for the possibility that a customer uses a limit immediately after it is checked but before the order is completed?
Asked once · last asked Mar 19 · Scenario · Senior
How can two concurrent orders both be accepted when the customer has enough funds or limit for only one, and how would you prevent it?
Asked once · last asked Mar 19 · Scenario · Senior
How do you manage transactions in nested operations where one service calls another: propagate the same transaction context, use savepoints, or prevent inner services from opening transactions?
Asked once · last asked Mar 26 · Scenario · Senior
Other ways it was asked
- “How do you handle nested operations where one service calls another? Do you propagate the same transaction context, use savepoints, or prevent inner services from opening transactions?”
For a transactional system, how would you choose between a relational database such as SQL Server and MongoDB?
Asked once · last asked Apr 2 · Design · Mid-level
How would you design a production-ready solution to update a couple of fields on one million Dynamics 365 CRM records?
Asked once · last asked Apr 6 · Design · Senior
How would you implement an offline database strategy in an e-commerce app?
Asked once · last asked Apr 11 · Scenario · Mid-level
Where would you store images in a large-scale image management system?
Asked once · last asked Apr 13 · Design · Mid-level
What techniques can you use to scale a database horizontally across multiple machines?
Asked once · last asked Apr 13 · Design · Senior
When might hash-based sharding be unsuitable, even if it distributes data evenly across shards?
Asked once · last asked Apr 13 · Scenario · Senior
You need to store each customer's product price history for 1–20 years. Which type of database would you choose, and why?
Asked once · last asked Apr 15 · Scenario · Mid-level
Would data access and update frequency affect your database choice, or would you still choose a relational database?
Asked once · last asked Apr 15 · Scenario · Mid-level
How would you test a system that uses eventual consistency?
Asked once · last asked Apr 17 · Scenario · Senior
What is the HDFS block size, and how can it affect processing large files?
Asked once · last asked Apr 17 · Concept · Mid-level
How would you design a data architecture, pipeline, AI system, or knowledge platform, explaining the use case and main architectural components?
Asked once · last asked Apr 20 · Design · Senior
Other ways it was asked
- “Describe a data architecture, pipeline, AI system, or knowledge platform you helped design. What was the use case, what role did you play, and what were the architecture's main components?”
After receiving an HTTP PUT request with an object payload, how would an object storage service process and persist it?
Asked once · last asked Apr 22 · Design · Senior
What storage medium would you choose for an object store that must handle objects ranging from zero bytes to five gigabytes?
Asked once · last asked Apr 22 · Design · Senior
How would you record an object in an object storage system so it can be found later by its key and returned to the client?
Asked once · last asked Apr 22 · Design · Senior
Which replication strategy would you favor for an object storage system, and why?
Asked once · last asked Apr 22 · Design · Senior
What are the trade-offs of scheduled file replication with rsync compared with other replication strategies?
Asked once · last asked Apr 22 · Design · Senior
Would database replication be suitable for replicating five-gigabyte objects in an object storage system?
Asked once · last asked Apr 22 · Design · Senior
What are the trade-offs of asynchronously replicating an object after the user's request completes?
Asked once · last asked Apr 22 · Design · Senior
What are the downsides of waiting to acknowledge an object upload until it has been replicated?
Asked once · last asked Apr 22 · Design · Senior
If you were building a chat application, which type of database would you choose?
Asked once · last asked Apr 23 · Scenario · Mid-level
How would you design a caching layer for a frequently accessed product catalog in a back-end service? How would you decide what data to cache and handle cache invalidation to maintain data consistency?
Asked once · last asked May 8 · Design · Senior
Where would you place a database, and how would you configure it to perform quickly for users around the world?
Asked once · last asked May 11 · Design · Senior
How would you architect cross-game sweepstakes credits earned and redeemed across games, using game, payment, and account events plus Kafka, Flink, Spark, Trino, ClickHouse, and Postgres to support near-real-time product analytics, auditable event trails for Compliance, and accurate daily reconciliations for Finance?
Asked once · last asked May 12 · Design · Senior
Other ways it was asked
- “A cross-game feature lets players earn sweepstakes credit in one game and redeem it in another. Product needs near-real-time analytics, Compliance needs an auditable event trail, and Finance needs accurate daily reconciliations. Given events from game, payment, and account services and Kafka, Flink, Spark, Trino, ClickHouse, and Postgres, what data platform architecture would you propose?”
How do you design transactional boundaries when a request touches aggregates or tables, and how do you handle partial failures in that context?
Asked once · last asked May 16 · Design · Senior
When a request involving multiple aggregates or tables partially fails, how do you handle rollback or compensating actions?
Asked once · last asked May 16 · Scenario · Senior
How do you manage major database schema changes while preserving backward compatibility?
Asked once · last asked May 18 · Scenario · Senior
Given Kafka data streaming into 40–50 PostgreSQL staging tables, how would you design near-real-time processing that transforms the data within 15 minutes and publishes it to downstream Kafka, without batch jobs or scheduled orchestration?
Asked once · last asked May 18 · Design · Senior
Other ways it was asked
- “Given a system that streams data from Kafka across 40–50 tables into PostgreSQL as a staging layer, how would you design near-real-time processing that transforms the data within 15 minutes and publishes it to a downstream Kafka layer, without relying on batch jobs or scheduled orchestration?”
How do you view PostgreSQL compared with other databases, and which database do you prefer for real-time processing, and why?
Asked once · last asked May 18 · Design · Senior
How would you estimate the storage required for a year of continuous quadcopter sensor and imaging data?
Asked once · last asked May 20 · Design · Mid-level
What compression techniques or storage strategies would you recommend for quadcopter data to balance retention and storage efficiency?
Asked once · last asked May 20 · Design · Mid-level
How would you keep read and unread notification state consistent across multiple devices when a user reads a notification on one device?
Asked once · last asked May 23 · Design · Senior
How would you avoid conflicts if two devices update notification state at nearly the same time?
Asked once · last asked May 23 · Scenario · Senior
How is a data pipeline architected, from data ingestion through transformation, and which tools are used at each stage?
Asked once · last asked May 27 · Design · Mid-level
How would you design a system using Kafka or RabbitMQ to process large volumes of data or events in real time, addressing reliability, scaling, and performance challenges?
Asked once · last asked May 27 · Design · Senior
Other ways it was asked
- “Can you describe a system you built using Kafka or RabbitMQ to process large amounts of data or events in real time, including the reliability, scaling, and performance challenges you faced and how you solved them?”
Can you tell me about a complex MongoDB implementation you’ve worked on?
Asked once · last asked May 27 · Behavioral · Senior
What use cases would you use relational and nonrelational databases for?
Asked once · last asked May 28 · Concept · Mid-level
Other ways it was asked
- “How have you used relational and nonrelational databases, and what use cases did they support?”
How would you design a high-capacity data pipeline and address its technical challenges?
Asked once · last asked Jun 3 · Design · Senior
Other ways it was asked
- “Describe a high-capacity data pipeline you built, including its design and the challenges you addressed.”
How would you design a data platform architecture, define its goals, and evaluate whether it meets them?
Asked once · last asked Jun 3 · Design · Senior
Other ways it was asked
- “Describe a data platform architecture you designed, including its goals and how you evaluated whether it met them.”
What do you understand by a lakehouse, how does Iceberg fit into it, and can you design a lakehouse without Iceberg or with something else?
Asked once · last asked Jun 9 · Design · Senior
If you built an Iceberg lakehouse, how would you expose its data to downstream consumers outside AWS so they could access, download, and work with it?
Asked once · last asked Jun 9 · Design · Senior
How would consumers connect to a file-based Apache Iceberg lakehouse using JDBC?
Asked once · last asked Jun 9 · Design · Senior
Other ways it was asked
- “Where is the metadata required for JDBC access to a file-based Apache Iceberg lakehouse hosted?”
- “Where should a JDBC query be sent when querying an Apache Iceberg lakehouse?”
What solution would you use to expose Apache Iceberg data to someone outside AWS who does not have EMR?
Asked once · last asked Jun 9 · Design · Senior
How should a postal-office application handle transaction and tracking numbers: send them to a central server or store them locally?
Asked once · last asked Jun 11 · Scenario · Mid-level
Tell me about a data platform project where you led the end-to-end architecture. How did it go, and what did you learn?
Asked once · last asked Jun 16 · Behavioral · Senior
What criteria would lead you to replicate data rather than consume it directly from the source?
Asked once · last asked Jun 16 · Scenario · Senior
A downstream consumer needs sub-10-millisecond p99 lookups of a customer profile by phone number. The data currently lives in S3, with Glue and Athena on top. What would you do?
Asked once · last asked Jun 19 · Design · Senior
How would you handle data synchronization issues when a mobile app regains connectivity after offline use?
Asked once · last asked Jun 24 · Scenario · Mid-level
When an uploaded image is assigned a generated ID, how would you determine which user it belongs to?
Asked once · last asked Jun 25 · Scenario · Mid-level
In a document review tool, how would you design an audit trail for OCR corrections so every downstream consumer can trace what changed, when, by whom, and why?
Asked once · last asked Jul 16 · Design · Senior
How would you handle potential data consistency issues between Redis and PostgreSQL in a real-time bidding system?
Asked once · last asked Jun 29 · Scenario · Senior
How would you decide whether to store groups in a database or represent them as Kafka events?
Asked once · last asked Jul 16 · Scenario · Mid-level
Walk me through the design decisions and considerations for implementing a hybrid lake house in a customer environment.
Asked once · last asked Jul 16 · Design · Senior
Other ways it was asked
- “How would you approach designing a hybrid lakehouse architecture?”
How does Iceberg federation work end-to-end and how would you implement it?
Asked once · last asked Jul 16 · Design · Senior
How would you build a data mesh across data platforms?
Asked once · last asked Jul 16 · Design · Senior
What target-state architecture would you propose for modernizing an on-premises Hadoop platform to Databricks on Azure?
Asked once · last asked Jul 16 · Design · Senior
In AWS, how would you design a scalable, cost-effective lakehouse pattern for ML and BI using S3 with Iceberg, Hudi, or Delta, and what would drive your choice among those table formats?
Asked once · last asked Jun 30 · Design · Senior
How would you adjust a request flow to keep an asynchronous pipeline consistent?
Asked once · last asked Jul 5 · Scenario · Senior
What caching mechanisms would you use to support an application scaling to 100,000 users?
Asked once · last asked Jul 16 · Scenario · Mid-level
When building a new product, what type of database would you choose?
Asked once · last asked Jul 16 · Scenario · Mid-level
What problems does Apache Iceberg solve that Delta Lake does not?
Asked once · last asked Jul 16 · Concept · Senior
What is caching, and how is it used in a CDN?
Asked once · last asked Jul 16 · Concept · Junior
How does a network using Nakamoto consensus determine which of two parallel branches is valid after a fork?
Asked once · last asked Jul 8 · Concept · Mid-level
What does a node do with its blocks when it determines that a neighboring chain is longer and has greater cumulative difficulty?
Asked once · last asked Jul 8 · Scenario · Mid-level
How do you determine the data storage architecture for a dataset?
Asked once · last asked Jul 16 · Design · Senior
How is Apache Iceberg different from Hive external tables?
Asked once · last asked Jul 16 · Concept · Mid-level
What storage considerations matter for Spark temporary files, and what roles do PostgreSQL, the Hive metastore, and Keycloak play?
Asked once · last asked Jul 16 · Concept · Senior
Why can object storage be slower than HDFS for some workloads?
Asked once · last asked Jul 16 · Concept · Senior
How would you design a software architecture to ensure transactional atomicity?
Asked once · last asked Jul 19 · Design · Senior
Other ways it was asked
- “Can you describe the software architecture and explain how it ensures transactional atomicity?”
How would you control how frequently different platforms are polled?
Asked once · last asked Jul 20 · Design · Mid-level
How would you control polling and relay frequency in a data pipeline while preventing duplicate data from being sent?
Asked once · last asked Jul 20 · Design · Senior
After Redis recovers, how would you determine how much data to use to repopulate the cache?
Asked once · last asked Jul 20 · Scenario · Senior
Where in a data pipeline would you apply custom classification logic for client-defined fields?
Asked once · last asked Jul 20 · Design · Senior
How would you approach ensuring data consistency across multiple services?
Asked once · last asked Jul 22 · Design · Senior
How would you mitigate a database bottleneck during a sudden 10x traffic spike?
Asked once · last asked Jul 22 · Scenario · Senior
Why use Amazon S3 in AWS if you already have a database?
Asked once · last asked Jul 26 · Concept · Mid-level
How would you migrate 500 million or more records without downtime or data loss?
Asked once · last asked Jul 27 · Design · Senior
In a large multi-tenant PostgreSQL schema, when would you choose partitioning by tenant versus keeping a single table with a tenant_id, and what performance or maintenance tradeoffs drive that choice?
Asked once · last asked Jul 27 · Design · Senior
How would you design an extraction component for a luxury real estate catalog platform?
Asked once · last asked Jul 27 · Design · Mid-level
Beyond testing, what would you do to make an application-level cache production-ready?
Asked once · last asked Jul 27 · Scenario · Senior
When would you use read replicas, and what problem do they address?
Asked once · last asked Jul 27 · Concept · Mid-level
What are the caveats of swapping database engines completely?
Asked once · last asked Jul 27 · Concept · Senior
For a transactional workload, what kind of database would you recommend?
Asked once · last asked Jul 27 · Scenario · Mid-level
What role can Redis play in a chat system design?
Asked once · last asked Jul 28 · Concept · Mid-level
Other ways it was asked
- “What role does Redis play in this chat system design?”
How would you choose between Redis and local in-memory storage for feature flags?
Asked once · last asked Jul 29 · Design · Mid-level
Other ways it was asked
- “What drove the decision to use Redis versus in-memory storage for feature flags?”
How would you take a four-source marketing data architecture from design through end-to-end implementation?
Asked once · last asked Jul 31 · Design · Senior
How would you determine the number of customers to migrate in each batch?
Asked once · last asked Aug 3 · Scenario · Senior
Why would you include a vector database in a system's architecture?
Asked once · last asked Aug 7 · Design · Mid-level
Other ways it was asked
- “Why would you use a vector database in this system?”
How can a data enrichment system work without third-party vendors, and what technologies might support it?
Asked once · last asked Aug 7 · Design · Senior
How would you preprocess labels and store them before delivery?
Asked once · last asked Aug 11 · Design · Senior
How would you design an ingestion layer that accepts data from various client devices, stores it safely, and treats redaction as a black box? What infrastructure tools would you use?
Asked once · last asked Aug 11 · Design · Senior
How can an event grouper determine which user actions belong together, and where should it store the grouping records?
Asked once · last asked Aug 14 · Design · Senior
When should a time-series database replace or complement a raw actions database, and can time-series capabilities be applied to raw-action storage?
Asked once · last asked Aug 14 · Design · Senior
Walk me through the chronological flow of user-generated actions through an event-processing system.
Asked once · last asked Aug 14 · Design · Senior
How would you approach the architecture to handle real-time processing and personalization?
Asked once · last asked Aug 17 · Design · Mid-level
What is the difference between a storage node, NAS, SAN, and local storage?
Asked once · last asked Aug 18 · Concept · Junior
When should an application use separate read and write databases?
Asked once · last asked Aug 20 · Concept · Senior
Is PostgreSQL using Raft for every transaction?
Asked once · last asked Aug 21 · Concept · Senior
How would you design an API integration to transfer three billion rows of daily production data to an insurance information center?
Asked once · last asked Aug 22 · Design · Senior
How would you approach a requirement from a client to ingest data from multiple sources like SQL Server, Oracle, Salesforce, and flat files into a single platform?
Asked once · last asked Aug 25 · Design · Senior
Where does the Hadoop ecosystem fit in a data engineering architecture?
Asked once · last asked Aug 25 · Concept · Mid-level
What are common sink options for a data pipeline, and how do you choose where to store processed data?
Asked once · last asked Aug 25 · Design · Junior
How would you prevent data science and BI workloads from interfering when they query the same underlying tables?
Asked once · last asked Aug 26 · Scenario · Senior
What architectural mechanisms allow secure data sharing to expose live data to external consumers without copying or moving files?
Asked once · last asked Aug 26 · Concept · Senior
How do you approach architecting an end-to-end data system when you inherit an architecture designed by another team or vendor?
Asked once · last asked Aug 26 · Scenario
How would you select a technology stack and build a data platform during its first 90 days?
Asked once · last asked Aug 26 · Scenario
How would you separate analytical, machine learning, and reporting data in a data architecture, and create a semantic layer for each?
Asked once · last asked Aug 26 · Design · Senior
How would you maintain data consistency during a legacy system migration?
Asked once · last asked Aug 26 · Design · Senior
Could you explain the architecture you would build when designing an ETL pipeline? What phases does the data pipeline go through?
Asked once · last asked Aug 29 · Design · Mid-level
When would you choose blob storage over disk storage?
Asked once · last asked Aug 30 · Concept · Mid-level
Other ways it was asked
- “Would you use blob storage or disk storage?”
How do you decide whether MongoDB is the right database technology for a project?
Asked once · last asked Aug 31 · Concept · Mid-level
If you were designing a data pipeline for a startup that is rapidly evolving, with budget constraints, how would you choose between a scalable cloud-based service and building a custom in-house solution?
Asked once · last asked Aug 31 · Design · Senior
What are event sourcing and projections, and how do they work together?
Asked once · last asked Aug 31 · Concept · Senior
How would you architect a cloud data platform, organize its data lake, and support different types of data consumers?
Asked once · last asked Aug 31 · Design · Senior
Other ways it was asked
- “Can you tell me about a cloud data platform you personally architected or helped build? How did you organize the data lake and support different types of data consumers?”
How would you design a data architecture that lets Spark, Snowflake, Microsoft Fabric, and other engines access shared data without creating separate copies, while allowing teams to subscribe to specific datasets?
Asked once · last asked Aug 31 · Design · Senior
How would you implement a reservation while an item is in the cart, so that the last available unit is held for 15 minutes and released if it isn’t purchased?
Asked once · last asked Sep 2 · Scenario · Senior
How can you expire a 15-minute inventory reservation without using a background job?
Asked once · last asked Sep 2 · Scenario · Senior
Given carte blanche, how would you approach designing a data pipeline system, starting simple?
Asked once · last asked Sep 2 · Design · Senior
What additional considerations would you account for when building a metrics ingestion and dashboarding flow?
Asked once · last asked Sep 2 · Design · Mid-level
How would you approach structuring and designing a CSV importer that handles varying file sizes and mappings?
Asked once · last asked Sep 2 · Design · Senior
In a batched CSV import, should the batch worker insert records before dispatching row-level jobs, or should it delegate insertion and hydration to the final worker layer?
Asked once · last asked Sep 2 · Design · Senior
How would you migrate data for a live service?
Asked once · last asked Sep 4 · Scenario · Senior
How would you design a bulk process for 2,000,000 rows that fails after 800,000 so it can restart safely without reprocessing completed rows?
Asked once · last asked Sep 4 · Design · Senior
Can you explain the Power BI architecture end to end, generally?
Asked once · last asked Sep 4 · Design · Senior
How would you store chatbot course data, including titles, descriptions, and video files?
Asked once · last asked Sep 5 · Design · Mid-level
Which database would you choose for vector embeddings to handle production scale of 10,000 users?
Asked once · last asked Sep 8 · Scenario · Senior
An e-commerce website generates 8,000 to 9,000 clicks per second, and the data must be stored for future analysis. Which GCP storage infrastructure would you choose?
Asked once · last asked Sep 9 · Design · Senior
How would you design an end-to-end data pipeline for 5 million customer records per day, including ingestion, transformation, storage, restoration, and visualization?
Asked once · last asked Sep 9 · Design · Senior
Other ways it was asked
- “How would you design an end-to-end data pipeline to ingest, transform, store, orchestrate, and visualize 5 million customer records per day?”
Which distributed system would you use to process 5 million customer records per day in a data pipeline?
Asked once · last asked Sep 9 · Design · Mid-level
For a trading business, is it ideal to run multiple database clusters on a single VM, with a separate database in each cluster, at large scale? If not, what architecture would be more suitable?
Asked once · last asked Sep 10 · Design · Senior
In a cloud environment, what Spark features make it preferable to one large machine for datasets with huge memory requirements?
Asked once · last asked Sep 10 · Concept · Senior
What consistency trade-offs would you accept between ledger commit and event processing?
Asked once · last asked Sep 11 · Design · Senior
Other ways it was asked
- “What consistency tradeoffs did you accept between ledger commit and event processing?”
How would you design a system to handle a very large database of files and store their data in a vector database?
Asked once · last asked Sep 13 · Design · Mid-level
What are the key components a data platform needs to ingest batch, streaming, and diverse enterprise data sources?
Asked once · last asked Sep 14 · Design · Senior
How would you approach a heavy-load system by choosing between sharding and other options?
Asked once · last asked Sep 15 · Design · Senior
When data files are stored in Amazon S3, what are the trade-offs between using Protocol Buffers and having an analytics system read the files directly?
Asked once · last asked Sep 15 · Design · Senior
How would you design Kafka topics, brokers, partitions, and Flink jobs to handle millions of user requests?
Asked once · last asked Sep 17 · Design · Senior
What should a system do if a sensor dataset is deleted?
Asked once · last asked Sep 18 · Scenario · Mid-level
How do you configure cross-region replication?
Asked once · last asked Sep 18 · Tooling · 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
What would you do if the application crashed after writing to the database but before publishing the event?
Asked once · last asked Sep 18 · Scenario · Senior
What are the risks of writing likes from a controller directly to Redis using a post key?
Asked once · last asked Sep 18 · Scenario · Senior
What would you store in Redis to make like counts and user-like lookups both fast and accurate?
Asked once · last asked Sep 18 · Design · Senior
How would you quickly show a user that they have already liked a post, including when they sign in from another device?
Asked once · last asked Sep 18 · Design · Senior
How would you connect an anonymous user's activity history with their activity after they register?
Asked once · last asked Sep 18 · Scenario · Senior
How would you store activity and user-created data for a temporary user who has not registered yet?
Asked once · last asked Sep 18 · Design · Senior
How would you create a data solution using healthcare data?
Asked once · last asked Sep 19 · Design · Mid-level
How would you decide whether multiple databases should share a server or run on separate servers?
Asked once · last asked Sep 21 · Design · Mid-level
How can three databases share a dedicated server while being organized into separate clusters?
Asked once · last asked Sep 21 · Design · Senior
How would you scale a database independently, and would you use the same one-master, three-worker architecture for it?
Asked once · last asked Sep 21 · Design · Senior
How would you plan data migration and database architecture during a technology-stack migration?
Asked once · last asked Sep 21 · Scenario · Senior
How would you address scaling bottlenecks when a relational database such as MySQL or PostgreSQL already has read replicas?
Asked once · last asked Sep 21 · Scenario · Senior
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More System Design interview questions
- All System Design interview questions
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- API Design and Messaging Interview Questions
- Scalability and Reliability Interview Questions
- Cloud Architecture and Multitenancy Interview Questions
- AI System Design Interview Questions
- System Design Interview Case Study 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 System Design 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.
942 interviews, 495 candidates, Oct 2025 to Oct 2026. Updated every month with new interviews.
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