30+ MongoDB Interview Questions to Hire MongoDB Developers

MongoDB is a widely used document-oriented, open-source database designed to store a large scale of data. It is categorized under the NoSQL database because it does not rely on tables and rows, making it easier to manage and scale. (Source: GeeksforGeeks)

This database management system offers several advantages over traditional databases:

• Flexibility in handling unstructured data
• Supports horizontal scaling
• Simple installation
• Cost-effective
• Data is easily accessible

MongoDB is critical in modern tech because it creates fast systems and handles enormous amounts of data. This database is ideal for CMS (content management systems), data analytics, real-time applications, etc.

Many organizations like Facebook, Google, and Amazon use MongoDB to power their applications and services. Its flexible data model and ease of integration with other technologies make it the best choice for modern database systems.

As more companies adopt MongoDB, there's a growing demand for professionals with these skills. Companies seek developers who can design, maintain, and develop MongoDB databases. Job roles like Database Administration, Developer, Database User, and Data Architect are in high demand.

As a recruiter, it is vital to ask the right MongoDB interview questions before selecting the candidate. It helps you ensure developers have the necessary skills and experience to work with MongoDB. It will also help you assess a developer's problem-solving skills, ability to work collaboratively, and approach to database design and optimization.

Overall, these interview questions will help you identify if the candidate fits the specific role while reducing the risk of bad hires.

To help you out, we have created a list of MongoDB interview questions that will help you hire the best MongoDB developers.

Basic MongoDB Interview Questions

1. What is a Document in MongoDB?

2. What are the data types in MongoDB?

3. What are Databases in MongoDB?

4. By default, which index is created by MongoDB for every collection?

5. Which are the different languages supported by MongoDB?

6. Explain the structure of ObjectID in MongoDB.

7. Explain the difference between MongoDB and MySQL.

8. What is a replica set?

9. How do we perform sorting in MongoDB?

10. How do we create a database in MongoDB?

Intermediate MongoDB Interview Questions

1. Explain Capped Collection.

2. How is Querying done in MongoDB?

3. How do you delete using the CRUD API in MongoDB?

4. What are Geospatial Indexes in MongoDB?

5. What are the different kinds of Indexes in MongoDB

6. What happens if an index does not fit into RAM?

7. Explain the Replication Architecture in MongoDB.

8. How to use the select * group by MongoDB aggregation?

9. What is the syntax of the limit () and sort () method?

10. What is the syntax of the skip () method?

Advanced MongoDB Interview Questions

1. What is the Aggregation Framework in MongoDB?

2. What are some utilities for backup and restoring in MongoDB?

3. Differentiate MongoDB and CouchDB.

4. How to perform the Join operations in MongoDB?

5. What is the syntax of the limit () method?

6. Which method is used to update documents into a collection?

7. Will you create Compound Index with "sex" first or "name" first?

8. What is Index Cardinality, and why does it matter?

9. How would you design the One-to-Squillions relationship in MongoDB?

10. Explain the procedure of starting the MongoDB server/instance.

What Are the Strategies for Hiring Top MongoDB Talent?

Now that you found our list of the best MongoDB interview questions to ask candidates. The next step involves determining the best fit among a pool of MongoDB developers. For this, you must adopt a more comprehensive approach to the screening and selection process.

As a recruiter, you must be familiar with the top must-have skills to look for while hiring MongoDB developers.

Skills like:

• Maintain and configure MongoDB instances
• Write procedures for backup and disaster recovery
• Design indexing strategies
• Configure, monitor, and deploy replica sets, etc.

But traditional screening methods may only provide a portion of a MongoDB developer's skills and abilities.

That is why you need to incorporate skills assessments, live coding interviews, or other performance-based evaluations, to accurately evaluate a candidate's potential for the job role.

Using an intelligent skills platform like iMocha to screen candidates before hiring them offers several advantages. It provides a more accurate evaluation of a candidate's skills and identifies top performers who are likely to succeed in the job role

Other advantages iMocha offers to hire MongoDB developers:

•  An extensive skill library to help you assess candidates with over 2500+ skills, including 100+ IT, 39+ SAP, 70+ Next-Gen, and more.
• It offers coding assessments to evaluate a developer's skills and knowledge, assessed using the same criteria. These assessments can include MCQs, Fill in the blanks, Whiteboard questions, AI-LogicBox, Live coding interviews, etc.
• iMocha Projects simulate real-world development scenarios. Developers are evaluated on their problem-solving skills, domain-specific expertise, understanding and ability to think through a project, etc.
• Behavioral assessments to evaluate a developer's soft skills, such as communication, teamwork, and problem-solving abilities. These assessments can include real-life business scenarios that developers may encounter in their jobs.
• AI-LogicBox to assess a developer's technical skills without writing the code from scratch.
• You can assess a developer's coding skills in real time with iMocha's Live Coding Interview feature.
• Other features include AI-based Proctoring, Automated Video Interviews, Candidate ID Verification, etc.

Check out iMocha’s MongoDB Online Test that is ideal to hire job-fit candidates.

Conclusion

The above set of MongoDB interview questions will help ensure your hiring process is effective and efficient. Asking them will ensure that there is no bias in the hiring process, candidates possess the necessary skills, and the candidate experience is improved. All of this can contribute to the organization's long-term success and growth.

FAQ

What are the most common MongoDB interview questions?

Here are some of the most common MongoDB questions that recruiters can ask to evaluate a candidate's MongoDB knowledge, experience, and problem-solving skills.

1. What is MongoDB, and how does it differ from traditional SQL databases?

2. Compare MongoDB with Cassandra.

3. What is the syntax for creating a new collection in MongoDB?

4. Compare MongoDB with Couchbase and CouchbaseDB.

5. What are indexes in MongoDB, and how do they improve performance?

6. What is MapReduce, and how is it used in MongoDB?

7. When do we use a namespace in MongoDB?

8. Can you explain the aggregation framework in MongoDB?

9. Explain the situation when an index does not fit into RAM.

10. What is the difference between MongoDB's $push and $addToSet operators?