An API key is a unique identifier used to authenticate a user or application when accessing an Application Programming Interface (API). It acts like a password, allowing developers to securely connect their software to external services or data sources. By using an API key, the service provider can track usage and manage access to their resources.
API keys are commonly used in various applications, such as web services, mobile apps, and cloud platforms. They help ensure that only authorized users can access specific features or data, enhancing security and preventing misuse of the service.