# NSAPI &Functions;

&reftitle.seealso;

NSAPI implements a subset of the functions from the Apache module for maximum compatibility.

## Apache functions implemented by NSAPI

Apache function (only as alias) | NSAPI function | Description
`apache_request_headers` | `nsapi_request_headers` | Fetch all HTTP request headers
`apache_response_headers` | `nsapi_response_headers` | Fetch all HTTP response headers
`getallheaders` | `nsapi_request_headers` | Fetch all HTTP request headers
`virtual` | `nsapi_virtual` | Make NSAPI sub-request

&reference.nsapi.entities.functions;