A quarter century has passed since the first browser was released. Tim Berners-Lee’s pioneering followed by Marc Andreessen's groundbreaking Mosaic browser come Navigator, spawned an industry that regaled in loading information onto a screen for users of the internet all over. But in 2019, webpage complexities have resulted in resource loading and rendering intricacies. Added, consumer comportment has shifted dramatically. Late 2016 saw the mobile client usage eclipse the desktop one for the 1st time in history. This has left developers with new found duties, notably: the disciplined delivery of data. We once referred to raw timing data provided by the browser to measure performance. The modern web experience soon demanded metrics beyond DOMContentLoaded and onLoad events. We've now introduced more complex measurements with Paint Timing API, Network Information API and Time To Interactive to name a few. Planet Of The APIs peruses present-day and even experimental APIs employed in assessing and accelerate resource loading and measuring page renders. And with an increasingly favourable browser landscape, we will look at how we can start to use these in the on going pursuit of providing stellar and speedy mobile user experiences.