How do you find one pixel in a billion? Cloud Optimized GeoTiffs are a new standard for raster data that support file-level access via the internet. Combined with serverless cloud technologies, raster data can now be queried by client-facing applications without the need for a spatial database or specialist server software. In this talk I present how we used COGs and serverless to build a fast and scalable application to query large raster data using point and polygon geometries. As well as providing an overview of the solution architecture, I’ll explore the challenges we face with large raster data and why we chose to develop the solution using these open source standards and technologies.