What Is Compression? | Marketing Dictionary
DICTIONARY · WEB

What is compression?

Reducing the size of files for faster transmission.

In plain English

Compression makes files smaller for the journey between server and browser. Text-based files like HTML, CSS and JavaScript compress dramatically, often to a fraction of their original size, and the browser unpacks them on arrival.

It is configured on the server, applies automatically once enabled, and is one of the least glamorous and highest-return performance settings available.

What to know

Enabled at server level
Modern servers support gzip and brotli. Most hosts enable it by default, but not all, and it is worth confirming.
Text compresses enormously
Markup, stylesheets and scripts shrink hugely. Already-compressed formats like JPEG and PNG gain little.
Images are a separate discipline
Image compression means choosing formats and quality levels, which is different work from server compression.
Check rather than assume
A page speed test will tell you whether text compression is active. It takes seconds to verify.

Why it matters

Compression reduces what actually travels over the network, which is exactly what a visitor on a mediocre mobile connection is waiting for. Because it is a switch rather than a project, it is the first thing to confirm before more involved performance work.

Common mistakes

×Assuming compression is on without checking.
×Confusing server compression with image compression and doing neither properly.
×Compressing images so hard that quality visibly suffers.
×Optimising code weight while ignoring uncompressed media.

FAQs

How do I check if compression is enabled?

Run a page speed test or check response headers. Any speed tool will flag uncompressed text resources.

Is brotli better than gzip?

Generally yes, slightly smaller output. Either is a large improvement over none, so do not delay for the choice.

WRITTEN BY TARIQ SALLAM
Marketing Consultant. Entrepreneur. Content Creator.

I'm a marketing consultant, entrepreneur and content creator. I help businesses grow through practical marketing, websites, SEO, content and AI.

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