Our Databases sources
Made Kerbsides hasn't been an easy task, as any other platform. We have a good base with the work of aminyasser that you can find at https://github.com/aminyasser/twitter-clone wich we´ve used.
But would be impossible integrate all the features without the Australian Post Codes - Matthew Proctor for Kerbsides (https://www.matthewproctor.com/australian_postcodes).

In the case of Spain, we found a file from GeoNames https://download.geonames.org/export/zip/ that we have to organize to fit our needs but the work is worth.
That's how we build the features for the site to get directions, distances from (Harvensine formula), filters, searches...

So we thought a good way to give back the favor is share the database also, check it out here: https://github.com/australopythecu/codigospostales/ (un array JS y la base de datos mysql customizable con Códigos Postales de España [localidad, provincia, codigo postal, coumidad autonoma, lat, lng] basada en la información de GeoNames).