100+ Free Couchbase Developer Practice Questions

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What does the Couchbase N1QL (SQL++) query `SELECT name, price FROM `travel-sample`.inventory.hotel WHERE price < 200` do?

Retrieves the document key and type for hotels priced under 200

Returns the name and price fields from documents in the hotel collection where price is less than 200

Updates hotel documents to set the price to 200 for qualifying records

Creates a new collection filtering hotels under 200

to track

2026 Statistics

Key Facts: Couchbase Developer Exam

~60

Exam Questions

Couchbase

90 min

Time Limit

Couchbase

70%

Passing Score

Couchbase

$200

Exam Fee

Couchbase

2 years

Validity

Couchbase

Practice Questions

OpenExamPrep

The Couchbase Certified Developer exam (~60 questions, 90 min, 70% passing, $200) covers N1QL (SQL++) queries, GSI indexing (covering/partial indexes, defer build), key-value operations (insert/upsert/replace, CAS, getAndLock, Sub-Document API), bucket/scope/collection hierarchy, vBuckets, Couchbase services, ACID transactions, durability levels, and document design patterns. Verify the current blueprint on learn.couchbase.com.

Sample Couchbase Developer Practice Questions

Try these sample questions to test your Couchbase Developer exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1In Couchbase, what is the fundamental unit of data storage that replaces the concept of a table row in a relational database?

A.Collection

B.Document

C.Bucket

D.Scope

Explanation: In Couchbase, data is stored as JSON documents, each identified by a unique document key. Documents are the fundamental data unit — equivalent to a row in SQL but schema-flexible. Each document can have a different structure within the same collection.

2What does the Couchbase N1QL (SQL++) query `SELECT name, price FROM `travel-sample`.inventory.hotel WHERE price < 200` do?

A.Retrieves the document key and type for hotels priced under 200

B.Returns the name and price fields from documents in the hotel collection where price is less than 200

C.Creates a new collection filtering hotels under 200

D.Updates hotel documents to set the price to 200 for qualifying records

Explanation: This N1QL query SELECTs the `name` and `price` fields FROM the `hotel` collection in the `inventory` scope of the `travel-sample` bucket, filtering documents WHERE the `price` field is less than 200. N1QL (SQL++) extends SQL with JSON navigation capabilities.

3In Couchbase, what is the primary difference between a Bucket, a Scope, and a Collection?

A.Bucket is a document, Scope is a field, Collection is a value

B.Bucket is the top-level storage container; Scope is a namespace inside a Bucket grouping Collections; Collection is a logical set of documents within a Scope

C.They are all synonyms for the same concept at different scale levels

D.Bucket stores binary data; Scope stores JSON; Collection stores relational tables

Explanation: Couchbase uses a three-level hierarchy: Bucket (top-level container, like a database) → Scope (namespace grouping, like a schema) → Collection (document grouping, like a table). Full keyspace notation is `bucket.scope.collection`. This hierarchy was introduced in Couchbase Server 7.0.

4Which Couchbase N1QL statement creates a Global Secondary Index (GSI) on the `email` field of the `users` collection in the `app` scope of the `myapp` bucket?

A.CREATE INDEX idx_email ON `myapp`.app.users (email) USING GSI

B.CREATE INDEX idx_email ON `myapp`.app.users WHERE email IS NOT NULL

C.INDEX CREATE ON users.email USING GSI

D.ALTER TABLE users ADD INDEX idx_email (email)

Explanation: `CREATE INDEX index_name ON keyspace (field) USING GSI` is the N1QL DDL syntax for creating a Global Secondary Index. GSIs are stored on Index service nodes and enable efficient secondary key lookups. The `USING GSI` clause explicitly specifies the Global Secondary Index type.

5In the Couchbase SDK, what is the difference between a `get` operation and a `getAndLock` operation?

A.`get` fetches the document; `getAndLock` fetches the document AND locks it for a duration, preventing other writers from modifying it

B.`get` is synchronous; `getAndLock` is asynchronous

C.`getAndLock` returns both the document and its CAS value; `get` does not return CAS

D.`getAndLock` is used for binary data; `get` is used for JSON documents

Explanation: `getAndLock(key, lockDuration)` retrieves the document and places a pessimistic write lock on it for the specified duration (max 30 seconds). Other writers attempting to modify the locked document will receive a CAS mismatch error until the lock expires or is released via `unlock`.

6What is CAS (Compare and Swap) in Couchbase and when would you use it?

A.CAS is a compression algorithm used to reduce document storage size

B.CAS is an opaque token representing the current version of a document; it enables optimistic concurrency control by ensuring a write only succeeds if the document hasn't changed since it was read

C.CAS is a Couchbase Authentication Service for managing user credentials

D.CAS is a cache eviction metric showing how often documents are accessed

Explanation: CAS (Compare and Swap) is a 64-bit opaque value unique to each document version. When you read a document, you receive its CAS. When you update, you pass the CAS value back; Couchbase rejects the write if the document has been modified by another operation (different CAS). This enables optimistic concurrency without locking.

7In Couchbase N1QL, what does the `USE KEYS` clause do?

A.Specifies the index to use for the query

B.Retrieves specific documents by their document key, bypassing index lookups

C.Defines the primary key field within a JSON document

D.Grants query access to specific users by key name

Explanation: `SELECT * FROM bucket USE KEYS ["key1", "key2"]` fetches documents directly by their document keys (IDs) without using an index. This leverages Couchbase's key-value store for O(1) lookups and is the most efficient way to retrieve specific documents when you know their keys.

8Which Couchbase service is responsible for executing N1QL queries?

A.Data service

B.Index service

C.Query service

D.Eventing service

Explanation: The Query service (running on Query nodes) is responsible for parsing, planning, and executing N1QL (SQL++) queries. It works in conjunction with the Index service to use GSIs for efficient data retrieval and the Data service for key-value fetches.

9In Couchbase, what is a Primary Index and when should you avoid using it in production?

A.A primary index is required for document key lookups; it should always be created on all buckets

B.A primary index (`CREATE PRIMARY INDEX`) indexes all document keys and allows N1QL to scan all documents; it should be avoided in production because full-collection scans are expensive

C.A primary index is automatically created on the `id` field of every document

D.A primary index is only available in the Enterprise edition of Couchbase

Explanation: `CREATE PRIMARY INDEX` creates an index on all document keys in the collection. While it allows any N1QL query to run (even without a covering GSI), it causes queries without field-specific indexes to perform full collection scans — expensive at scale. In production, specific GSIs on query fields are strongly preferred.

10What is the Couchbase Sub-Document API and what advantage does it offer over full document operations?

A.It is a query language for nested JSON paths, similar to JSONPath

B.It allows reading or mutating specific fields within a document without fetching or transmitting the full document, reducing network I/O and improving performance

C.It is a special API for documents smaller than 1 KB

D.It provides field-level encryption for sensitive document fields

Explanation: The Sub-Document API (also called Subdoc) lets you perform operations (GET, MUTATE_IN, INSERT, UPSERT, REPLACE, ARRAY operations) on specific JSON paths within a document. This avoids the network overhead and write amplification of fetching and replacing the entire document when only one field changes.

About the Couchbase Developer Exam

The Couchbase Certified Developer validates skills to build production-grade applications on Couchbase Server: the bucket/scope/collection hierarchy, N1QL (SQL++) queries (SELECT, JOIN, NEST, UNNEST, INSERT, UPDATE, DELETE, MERGE, USE KEYS, META(), array comprehensions, MISSING handling), Global Secondary Indexes (GSI, covering indexes, partial indexes, defer build), key-value operations (insert/upsert/replace/get, CAS optimistic locking, getAndLock pessimistic locking, Sub-Document API), binary counters, Distributed ACID Transactions, durability levels, Couchbase services (Data, Index, Query, Search, Eventing, Analytics), Couchbase Mobile, and document design patterns.

Assessment

Multiple-choice questions delivered online with proctoring

Time Limit

90 minutes

Passing Score

70%

Exam Fee

$200 USD (Couchbase / Couchbase Academy)

Couchbase Developer Exam Content Outline

~20%

Couchbase fundamentals

Bucket/Scope/Collection hierarchy, vBuckets (1,024 partitions, CRC32 key hashing), Couchbase services: Data (KV), Index (GSI), Query (N1QL), Search (FTS), Eventing (JS triggers), Analytics (CBAS). Document model: JSON documents, 20 MB max size, document keys.

~35%

N1QL (SQL++) queries

SELECT/FROM/WHERE/GROUP BY/ORDER BY/LIMIT/OFFSET, JOIN and NEST (flattened vs nested output), UNNEST (array expansion), USE KEYS (direct key lookup), META() (document key, expiration, CAS), INSERT/UPSERT/UPDATE/DELETE/MERGE DML, EXPLAIN (query plan), MISSING vs NULL, ARRAY comprehensions, OBJECT_ADD/OBJECT_PUT functions, ARRAY_FLATTEN/ARRAY_APPEND functions.

~20%

Indexing and performance

GSI (Global Secondary Index): CREATE INDEX ... USING GSI, covering indexes (all query fields in index), partial indexes (WHERE condition), composite indexes, INCLUDE clause, DEFER BUILD + BUILD INDEX (batch index creation), index replicas (WITH {"num_replica": N}), EXPLAIN to verify index usage and fetch elimination.

~15%

Key-value operations

insert (fail if exists), upsert (create or replace), replace (fail if not exists), get, remove. CAS: optimistic concurrency token, update rejected on version mismatch. getAndLock/unlock: pessimistic locking up to 30s. Sub-Document API: lookupIn (get fields), mutateIn (set/insert/upsert/replace/arrayAppend/increment). binary().increment/decrement. getAndTouch (fetch + refresh TTL). Distributed ACID Transactions: transactions.run() lambda.

~10%

Advanced topics

Durability levels: None, Majority, MajorityAndPersistToActive, PersistToMajority. Couchbase Eventing: OnUpdate/OnDelete JavaScript functions, mutation triggers. FTS vs N1QL: FTS for stemming/fuzzy/relevance; N1QL for exact-match, aggregation. Analytics (CBAS): isolated workload, shadow dataset. Couchbase Mobile: Couchbase Lite + Sync Gateway offline-first sync. Document design: embed vs reference, 20 MB limit.

How to Pass the Couchbase Developer Exam

What You Need to Know

Passing score: 70%
Assessment: Multiple-choice questions delivered online with proctoring
Time limit: 90 minutes
Exam fee: $200 USD

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

Couchbase Developer Study Tips from Top Performers

1Master N1QL keyspace notation: `bucket`.scope.collection and the USE KEYS clause for direct key lookups.

2Know insert vs upsert vs replace: insert fails on duplicate, replace fails on missing, upsert never fails on key conflicts.

3Understand CAS (optimistic) vs getAndLock (pessimistic) concurrency — when to use each.

4Know what a covering index is: the query plan shows no Fetch step when all needed fields are in the index.

5Understand DEFER BUILD for efficient batch index creation (create definitions first, build all at once).

6Know MISSING vs NULL: MISSING = path does not exist in the document; NULL = path exists but value is null.

7Practice UNNEST vs NEST: UNNEST creates one row per array element; NEST embeds matching docs as a nested array.

Frequently Asked Questions

How many questions are on the Couchbase Certified Developer exam?

The Couchbase Certified Developer exam is approximately 60 multiple-choice questions completed in 90 minutes, delivered online with proctoring. Always verify the exact count and time limit on the official learn.couchbase.com page before scheduling.

What score do I need to pass the Couchbase Certified Developer exam?

The passing score for the Couchbase Certified Developer is approximately 70%. Aim for 80%+ on practice sets before scheduling to give yourself a margin against unexpected question phrasing.

How much does the Couchbase Certified Developer exam cost?

The Couchbase Certified Developer exam is approximately $200 USD. Verify the current pricing on the official learn.couchbase.com page before scheduling.

What is the difference between insert, upsert, and replace in Couchbase?

`insert` creates a new document — it fails with DocumentExistsException if the key already exists. `upsert` creates the document if it does not exist or replaces it if it does — never fails due to key conflicts. `replace` modifies an existing document — it fails with DocumentNotFoundException if the key does not exist.

What topics are on the Couchbase Certified Developer exam?

Topics include N1QL (SQL++) queries (SELECT, JOIN, NEST, UNNEST, USE KEYS, META(), MERGE, DML), GSI indexing (covering/partial indexes, DEFER BUILD), key-value operations (CAS, getAndLock, Sub-Document API, binary counters), Couchbase services architecture, Distributed ACID Transactions, durability levels, Eventing, Full Text Search, Analytics, Couchbase Mobile, and document design patterns.

Does the Couchbase Certified Developer certification expire?

The Couchbase Certified Developer certification is valid for 2 years. Recertification is required to maintain active status. Verify recertification requirements on learn.couchbase.com.