Although always a popular format, with the recent specification of Cloud Optimized GeoTIFFs, the TIFF format has had a renaissance as a cloud enabled storage format. Traditional processing software like GDAL took advantage of that, but is not available for browsers and had to rely on server-side processing instead. The geotiff.js library provides a pure JavaScript implementation of the TIFF format and allows the efficient exploitation of large raster datasets with the full range of values and metadata. In this talk, the architecture and techniques used that makes geotiff.js access so efficient will be explained. Additionally recent additional functionalities and developments by growing community will be highlighted. The COG-explorer is a demo application to show the capabilities of geotiff.js by allowing to browse TIFF files on top of an OpenLayers map. It allows to access large TIFF files on remote sources and can combine multiple files and rendering mechanisms to generate visually impressive images. It provides advanced and efficient rendering techniques using WebGL and takes full advantage of the layout of cloud optimized GeoTIFFs and the capabilities of geotiff.js.