Apache is a long-established, open-source web server that delivers web pages to visitors.
Apache, properly called the Apache HTTP Server, is software that runs on a server and answers requests from browsers. When a visitor opens your site, Apache receives the request, finds the right file or runs the right script (often PHP), and sends the page back.
It was first released in 1995 and is maintained by the Apache Software Foundation. For many years it powered the majority of websites on the internet, and it's still widely used on shared hosting, in tutorials and in software documentation.
How the Apache web server works
Apache listens for incoming connections, usually on port 80 for HTTP and port 443 for HTTPS. It decides what to do with each request using its configuration files and modules.
- Modules add features, such as mod_rewrite for clean URLs, mod_ssl for encryption and mod_deflate for compression.
- Multi-Processing Modules (MPMs) control how Apache handles many visitors at once. The older prefork model uses one process per connection, while event and worker use threads and handle more traffic with less memory.
- .htaccess files let you change settings for a single folder without touching the main config. This is why Apache became so popular on shared hosting.
Why Apache matters for your website
Most PHP apps, including WordPress, were built and tested with Apache in mind. Their instructions often say "add this to your .htaccess file" for redirects, security rules or caching headers. If your host's web server understands those rules, you can follow that advice as written.
Apache vs Nginx vs LiteSpeed
- Apache: flexible and compatible, with per-folder .htaccess support. It can be slower and use more memory under heavy load, especially with the prefork model.
- Nginx: fast at serving static files and handling many connections, but it doesn't read .htaccess files, so rules must be rewritten into its own config.
- LiteSpeed: a drop-in Apache replacement that reads .htaccess and Apache-style rewrite rules, with an event-driven design and built-in page caching.
If you move a site from Apache to LiteSpeed, your .htaccess rules usually carry over without changes.
Common Apache issues
- 500 Internal Server Error: often a typo in .htaccess. Check the error log for the exact line.
- Redirect loops: two rewrite rules sending visitors back and forth, common when forcing HTTPS or www.
- Slow under traffic: too many processes for the available memory, which a cache or a faster web server helps with.
Every AblePage plan uses LiteSpeed rather than Apache, so your existing Apache-style rules still apply.