Apache2handler

Apache2handler is the PHP Server API (SAPI) used when PHP is built as an Apache 2.x module, allowing PHP code to run inside the Apache process as mod_php. It provides in-process execution of PHP scripts, enabling direct integration with the Apache request handling pipeline without invoking an external gateway interface.

Implementation and loading

Apache2handler is compiled into PHP as an Apache module or loaded as a shared object (for example, libphp7.so) and loaded by Apache via the LoadModule directive. PHP files are mapped to the handler using Apache configuration directives such as SetHandler or AddType, for example, SetHandler application/x-httpd-php or AddType application/x-httpd-php .php. The configuration combines Apache’s module loading with PHP’s internal interpreter to process requests.

Usage and compatibility

The Apache2handler SAPI is commonly used with the prefork MPM, where each request is handled by a separate process, which aligns with PHP’s traditional thread-safety model. It is less suitable for threaded MPMs (such as worker or event) unless using a thread-safe PHP build or alternative configurations. Modern deployments often prefer alternatives like PHP-FPM with FastCGI for better scalability on threaded MPMs.

Performance and resource considerations

As an in-process SAPI, Apache2handler can offer low latency and high through‑put for PHP requests, but it ties PHP execution to Apache processes. This can lead to higher memory usage under load compared with external PHP interfaces, particularly on busy sites.

Deprecation and alternatives

While still supported in many setups, Apache2handler has contrast with more scalable patterns such as FastCGI or PHP-FPM. Many administrators migrate to FastCGI/PHP-FPM to decouple PHP from the web server and improve performance and reliability.

See also: PHP, Apache HTTP Server, SAPI, mod_php, FastCGI, PHP-FPM, Apache 2.x.