https://grid.plus.codes/ shows grid generation working with different map
providers, including free OpenStreetMaps (click "LEAFLET" or "OPENLAYERS").
Source code for the grid server is here:
https://github.com/google/open-location-code/tree/main/tile_server
Sample code to integrate with free map
Hi,
There are open source implementations of open location code that don't
require any network dependency.
For java, see:
https://github.com/google/open-location-code/blob/main/java/src/main/java/com/google/openlocationcode/OpenLocationCode.java
For PHP there are a couple implementations hosted