Interceptors in NestJS

In modern backend application, there are many situations where you want to execute logic before or after a request reaches your controller methods.

Examples include:

• Logging requests and responses
• Transforming API responses
• Handling caching
• Measuring execution time
• Adding metadata
• Sanitizing output
• Serializing entities
• Monitoring performance

Instead of duplicating this logic in every controller or service, NestJS provides a powerful feature called Interceptors.