Analysis of Website Performance Optimisation Techniques for Mobile Users in Low-Bandwidth Environments

The proliferation of mobile internet access in sub-Saharan Africa has made website performance optimisation a matter of critical engineering importance. Mobile users on constrained networks face severe delays from oversized images, weak caching policies and unoptimised front-end code. This study experimentally evaluates three widely adopted front-end optimisation methods, image compression, browser caching and code minification, across ten representative Nigerian websites. Evaluation used Google Lighthouse and PageSpeed Insights under two network conditions: Long-Term Evolution (LTE) and Slow Fourth-Generation (Slow 4G) throttling. Recorded metrics were page load time, total page size, number of resource requests and the composite Lighthouse performance score. Image compression reduced average page size by 38.1%; browser caching reduced repeat-visit load time by 43.3%; and code minification improved resource efficiency by 18.3%. Combined application of all three techniques achieved a mean load-time reduction of 50.5% and a Lighthouse score improvement of 28.1 percentage points, raising average scores from 54.9 to 83.0. Paired-sample t-tests confirmed that all improvements were statistically significant (p < 0.001), with very large effect sizes. These findings demonstrate that an integrated, multi-technique optimisation strategy delivers measurably superior outcomes and strongly supports its systematic adoption by developers serving bandwidth-constrained mobile users across Nigeria and sub-Saharan Africa. Further studies should extend this framework to server-side interventions, including Content Delivery Network deployment, Hypertext Transfer Protocol version 3 adoption and Brotli compression, and should incorporate real-user monitoring across diverse geographic and network contexts to validate the synthetic findings reported here.