What is HTTP Compression?
HTTP compression is a technique used in HTTP communication to reduce traffic by compressing the data returned by a web server into GZIP format before sending it to the client. This method, also referred to as GZIP encoding or GZIP compression, is compatible with HTTP/1.1 clients.
In HTTP up to version HTTP/1.1, web servers typically transmit files like HTML, CSS, and JavaScript as plain text to clients. Since these files often contain repeated strings or patterns, GZIP compression is highly effective, significantly reducing data size and improving web application performance. However, precompressed data formats like JPEG images or PDFs may see little to no benefit from HTTP compression and, in some cases, could even increase in size.
For servers using Apache, HTTP compression can be achieved using the mod_deflate module. However, enabling compression increases CPU usage, and for servers already under high load, response times may degrade. To avoid such issues, placing an Application Delivery Controller (ADC) between the server and the client is more effective for performing HTTP compression. For example, F5 BIG-IP includes built-in HTTP compression capabilities to optimize traffic.