Where a Compressing Proxy Can Save Bandwidth
Place content reduction before the constrained client link and account for image quality, existing compression and HTTPS visibility.
Place content reduction before the constrained link on the response path:
website → proxy transforms response → slow or metered link → browserIf the full body already crossed that link, shrinking it afterward cannot recover those bytes. A remote transformer with a faster upstream can serve a different purpose from a local proxy beside the browser.
Ziproxy illustrates the approach: its project describes a non-caching HTTP proxy that gzips text-like content and can produce smaller, lower-quality images.
| Response path | Potential reduction |
|---|---|
| Gzip coding | Lossless; the browser decodes original data |
| Image recompression | Can discard detail and be unsuitable when exact images matter |
| Already efficiently compressed content | Less room for further reduction |
| Ordinary HTTPS CONNECT | Opaque TLS prevents HTML/image transformation without another trusted plaintext-access arrangement |
Processing and the extra hop also take time, so fewer bytes do not guarantee faster completion. Caching reuses an eligible stored response; compression can transform a newly fetched one without storing it.
Where HTTP content is visible, honor Cache-Control: no-transform. The no-transform response policy governs compliant content handling; it is separate from transport encryption. Estimate benefits from the actual content and encryption path, not an old plaintext-image demonstration.