Backend Interview Practice - 60 Free Questions

Q: How many questions are in this practice set?

This practice set contains 60 questions with detailed explanations.

Q: What topics does this practice cover?

It covers the key topics and question types for Backend Interview, including vocabulary, grammar, reading, and practical test skills.

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Yes, every question includes a clear explanation so you can understand the correct answer and learn from mistakes.

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Your wrong answers, favorites, scores, and study streak are saved in your browser, so you can review them on the same device.

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You can practice randomly, take a timed mock exam, filter by difficulty, type, and topic, search questions, and review wrong answers.

Question 1

What is REST?

Select an answer A JavaScript libraryAn architectural style for designing APIsA database query languageA CSS framework

Question 2

What does HTTP status 200 mean?

Select an answer OKNot foundServer errorRedirect

Question 3

What does HTTP status 404 mean?

Select an answer SuccessUnauthorizedCreatedResource not found

Question 4

What does HTTP status 500 mean?

Select an answer Bad requestNot foundInternal server errorSuccess

Question 5

What is a GET request used for?

Select an answer Deleting a resourceUpdating a resourceRetrieving data without changing itCreating a resource

Question 6

What is a POST request used for?

Select an answer Creating a resourceReading a resourceCaching a resourceLogging a request

Question 7

What is idempotency?

Select an answer Requests are encryptedRepeating the same request has the same effect as one requestRequests always return the same responseRequests cannot fail

Question 8

What is an API endpoint?

Select an answer A database tableA server logA CSS classA URL that exposes a resource operation

Question 9

What is JSON?

Select an answer A database engineA web serverA CSS preprocessorA lightweight data interchange format

Question 10

What is API versioning?

Select an answer Rotating server logsManaging changes so existing clients keep workingCaching API responsesEncrypting API keys

Question 11

What is rate limiting?

Select an answer Restricting how many requests a client can make in a periodSlowing down database queriesLimiting response sizeCapping server memory

Question 12

What is a webhook?

Select an answer A CSS animationA database triggerA server-to-server callback triggered by an eventA browser plugin

Question 13

What is a database index?

Select an answer A structure that speeds up query lookupsA backup copy of a tableA foreign keyA transaction log

Question 14

What is normalization?

Select an answer Encrypting all columnsSplitting serversCompressing tablesOrganizing data to reduce redundancy and improve integrity

Question 15

What is a foreign key?

Select an answer A cached valueA column that references a key in another tableA unique identifier in the same tableAn index for sorting

Question 16

What is a transaction?

Select an answer A backup jobA database indexA group of operations that should succeed or fail togetherA single SELECT query

Question 17

What does ACID stand for?

Select an answer Access, Consistency, Identity, DataAtomicity, Consistency, Isolation, DurabilityAvailability, Consistency, Isolation, DistributionAtomicity, Caching, Indexing, Durability

Question 18

What is a NoSQL database?

Select an answer A non-relational database optimized for flexible schemasA database without securityA database that cannot scaleA SQL-only database

Question 19

Which database is document-based?

Select an answer RedisPostgreSQLMySQLMongoDB

Question 20

Which database is a key-value store?

Select an answer PostgreSQLCassandraRedisMongoDB

Question 21

What is sharding?

Select an answer Backing up tablesNormalizing schemasSplitting data across multiple serversEncrypting database files

Question 22

What is replication?

Select an answer Copying data to multiple nodes for availabilityDeleting duplicate rowsIndexing columnsCompressing tables

Question 23

What is a connection pool?

Select an answer A network firewallA set of reusable database connectionsA cache of query resultsA backup schedule

Question 24

What is an ORM?

Select an answer An object storage serviceA message queueA load balancerA tool that maps objects to database rows

Question 25

What is a database migration?

Select an answer Copying a database to another regionDeleting old logsRestarting a databaseApplying schema changes in a controlled way

Question 26

What is a query plan?

Select an answer An API designThe execution steps a database uses for a queryA backup planA SQL style guide

Question 27

What is caching?

Select an answer Storing frequently used data for faster accessEncrypting data in transitBacking up dataNormalizing schemas

Question 28

What is cache invalidation?

Select an answer Encrypting cached valuesAdding more cache nodesRemoving or updating stale cached dataDeleting the cache server

Question 29

What is a cache-aside pattern?

Select an answer Reading from cache and loading from the database on a missWriting to cache onlyNever using a databaseStoring all data in memory

Question 30

What is a CDN?

Select an answer A database clusterAn API gatewayA message brokerA network of edge servers that cache content

Question 31

What is a message queue?

Select an answer A cache layerA system for asynchronous communication between servicesA database tableA load balancer

Question 32

What is publish/subscribe?

Select an answer A DNS protocolA cache strategyA pattern where publishers send messages to subscribersA database replication mode

Question 33

What is a dead letter queue?

Select an answer A queue that never deliversA queue for messages that could not be processedA queue with no consumersA queue for deleted users

Question 34

What is authentication?

Select an answer Verifying who a user isChecking what a user can doEncrypting user dataLogging user actions

Question 35

What is authorization?

Select an answer Verifying a passwordCreating a sessionHashing dataChecking what permissions a user has

Question 36

What is hashing used for in security?

Select an answer Compressing filesRouting trafficStoring passwords as one-way digestsEncrypting API responses

Question 37

What is a JWT?

Select an answer A database indexA cache keyA signed token that carries claimsA JavaScript framework

Question 38

What is TLS?

Select an answer A protocol that encrypts traffic between clients and serversA load balancerA database engineA logging format

Question 39

What is CSRF?

Select an answer An HTTP methodAn attack that makes a user perform unwanted actionsA cache strategyA database lock

Question 40

What is horizontal scaling?

Select an answer Adding more CPU to one serverIncreasing disk sizeCompressing dataAdding more servers to handle load

Question 41

What is vertical scaling?

Select an answer Adding more serversMoving data to the cloudCreating replicasAdding more resources to a single server

Question 42

What does a load balancer do?

Select an answer Runs background jobsDistributes traffic across serversEncrypts database dataStores cache

Question 43

What is a reverse proxy?

Select an answer A server that fronts backend servers for clientsA database replicaA caching databaseA DNS resolver

Question 44

What is statelessness?

Select an answer The database has no stateRequests are always cachedThe server does not store client state between requestsThe server stores sessions in memory

Question 45

What is a microservice?

Select an answer A small, independently deployable serviceA database tableA CSS classA single monolithic app

Question 46

What is a monolith?

Select an answer A large databaseA server clusterA message queueA single application containing all features

Question 47

What is availability?

Select an answer The size of dataThe percentage of time a system is operationalThe speed of a requestThe number of users

Question 48

What is latency?

Select an answer The percentage of failed requestsThe amount of memory usedThe time a request takes to completeThe number of requests per second

Question 49

What is throughput?

Select an answer The cache hit rateThe number of requests a system can handle per secondThe response time of one requestThe uptime percentage

Question 50

What is a circuit breaker?

Select an answer A pattern that stops calls to a failing serviceA database lockAn electrical switchA caching layer

Question 51

What is graceful degradation?

Select an answer Shutting down all servicesRestarting a databaseRedirecting all trafficKeeping partial functionality when a service fails

Question 52

What is an API gateway?

Select an answer A message brokerA CSS frameworkA single entry point that routes, authenticates, and limits API callsA database connection pool

Question 53

What is eventual consistency?

Select an answer Data never changesData is deleted after readsData replicas converge to the same state over timeData is always immediately consistent

Question 54

What is pagination?

Select an answer Splitting API results into pagesEncrypting API responsesCaching every responseCompressing JSON

Question 55

What is a background job?

Select an answer A cache refresh onlyAn asynchronous task processed outside the requestA synchronous API callA database query

Question 56

What is observability?

Select an answer A security firewallA caching strategyA load balancerLogs, metrics, and traces that explain system behavior

Question 57

Which of the following are HTTP methods? Select all that apply.

Select an answer GETPOSTPUTFETCH

Question 58

Which of the following are database types? Select all that apply.

Select an answer RelationalDocumentKey-valueGraph

Question 59

POST requests are guaranteed to be idempotent.

Select an answer FalseTrue

Question 60

Match each HTTP status code to its meaning.

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