expires

The 'expires' directive is utilized to set expiration times for static resources served by NGINX. By defining how long a resource should be considered fresh, it aids in browser caching and optimizing load times by reducing the number of requests sent to the server. The directive accepts a time value as its argument, which can be specified in seconds (e.g., '30s'), minutes (e.g., '5m'), hours (e.g., '12h'), or days (e.g., '1d'). Additional options also exist whereby you can specify 'max' for indefinite expiration or 'epoch' to set it to a past date.

When set, the 'expires' directive will automatically generate the appropriate response headers for client requests. This can be configured in various contexts including 'http', 'server', and 'location'. Notably, it can also be used within 'if' statements inside a location block for more granular control. Caching policies can be tailored to different types of resources by leveraging multiple 'expires' directives across different contexts, thus ensuring that static files are efficiently served.