Hi KosPan81,

Thanks for reaching out!

I prefer using semicolons, as it's the standard separator for multiple values in OSM. As noted on the wiki: “The default separator for multiple values in OSM is the semi-colon.” Commas aren't standardized by the community, so I try to stay consistent with that guideline.

Also, just to clarify: addr:postcode and postal_code are different keys. The addr:postcode tag shouldn't be used on streets—if you noticed me tagging streets with addr:postcode, then that was definitely a mistake on my part. Thanks for catching it!

https://wiki.openstreetmap.org/wiki/Key:addr:postcode
https://wiki.openstreetmap.org/wiki/Key:postal_code