NoSQL databases (such as MongoDB, Cassandra, and Redis) are used when flexibility and scalability are essential, and data doesn't fit well into a traditional relational model. These databases are commonly used in various domains, including:

• 1.Social Media: To handle the massive amounts of data generated by social networking platforms.
• 2.Gaming: In online gaming platforms for user data, leaderboards, and game state storage.
• 3.IoT: For managing the vast data generated by IoT devices and sensors.
• 4.Big Data and Analytics: In big data applications for data storage and real-time analytics..
• 5.Real-Time Applications: NoSQL databases are used in real-time chat applications and collaborative tools.