Optimising a website for 3G connections

A fast office connection hides latency and packet loss that dominate mobile loading. The useful target is early readable content and a dependable task under a constrained, variable connection.

Measure with latency

Shape bandwidth and round-trip time, clear caches and record DNS, connection, request and rendering stages. A lower total page weight can still be slower if it is split across many serial discoveries and hosts.

Reduce connection setup

Consolidate essential assets on a small number of hosts, keep redirects out of the critical path and enable persistent connections and compression correctly. Review third-party tags that require additional DNS and handshakes.

Prioritise initial content

Place core HTML and required CSS early, defer non-essential scripts and avoid document.write dependencies. Keep the first view useful while below-the-fold images and enhancements continue loading.

Optimise images by use

Generate dimensions close to their rendered size, choose JPEG, PNG or simple CSS appropriately and test compression visually. Do not deliver a desktop hero and scale it down solely in the browser.

Design interruption recovery

Preserve form data, make submissions repeat-safe and give clear retry behaviour. Test a connection drop between request and response so the interface does not create duplicate orders or indefinite progress.