You can use Google Sheets and the OpenCage Geocoding API to quickly convert a list of coordinates to placenames (reverse geocoding) or vice versa (forward geocoding).
Please see the detailed tutorial on the OpenCage site.
We run a worldwide geocoding API and geosearch service based on open data. Learn more about us.
We also organize Geomob, a series of regular meetups for location based service creators, where we do our best to highlight geoinnovation. If you like geo stuff, you will probably enjoy the Geomob podcast.