Technical SEO
Compression
HTTP compression reduces representation bytes transferred between server and client using an encoding both endpoints support.
What it means
For compressible text resources, the client advertises encodings and the server can respond with an encoded representation plus `Content-Encoding`. Lossless algorithms such as Brotli or gzip commonly reduce HTML, CSS, JavaScript, JSON and SVG, while already compressed media often gains little.
Why it matters
Smaller text transfers can shorten resource-load duration, especially on constrained connections. Compression adds processing and cache variants, so configuration must handle `Accept-Encoding`, intermediaries and resource type rather than compressing every response indiscriminately.
Example
A server sends a 180 KB JavaScript bundle as Brotli when the browser supports it and maintains the correct `Vary: Accept-Encoding` behavior. A JPEG is left in its image encoding because wrapping it in gzip adds work with negligible savings.
Common mistakes
Do not confuse transfer compression with image quality settings, compress tiny or already compressed files blindly or omit variant-aware caching. Avoid enabling dynamic compression without Monitoring CPU cost and sensitive response behavior.
How AYSA handles this
Signals reviewed
Content-Type, Content-Encoding, transferred bytes, Accept-Encoding, cache variation
Problem AYSA can identify
AYSA can find large compressible text responses sent without encoding and responses whose cache variation is inconsistent.
Recommendation prepared
The proposal identifies eligible MIME types, preferred server or CDN configuration and resources excluded from recompression.
Approval preview
The user reviews current and encoded sizes, headers and infrastructure ownership before approval.
Execution
AYSA can change supported WordPress or web-server configuration when access permits; managed CDN settings may require the account owner.
Verification
AYSA requests multiple encoding variants, validates decoded content and compares transfer size, latency and server behavior.
Limits
Compression gains and CPU costs vary by content and infrastructure, and AYSA cannot change an inaccessible hosting layer.
Sources and further reading
- MDN — HTTP compression — Web platform reference
- MDN — Cache-Control — Web platform reference
- web.dev — Understand the critical path — Official Chrome documentation
Written by Marius Dosinescu. Reviewed by AYSA SEO Editorial Team · 2026-07-28 00:00:00.
Quick answers
Frequently asked questions
Should JPEG and video files also receive gzip or Brotli?
Usually not, because those formats already use compression and typically gain little from another HTTP compression layer.
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