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Not quite, I had to read up on this stuff recently.

Zip+4 only gets down to either a smaller geographic area, or an apartment / office building or a high volume mail recipient like a business that interacts a lot by mail. It's sort of assigned as needed by USPS rather than following any particular logic and is there to assist them with mail sorting.

Eircode is an actual geolocation service with an intention to be used for much more than mail sorting.

The main purpose of it was to deal with Ireland's issue with non-unique addresses and very verbose addressees that could cause a lot of confusion for couriers / taxies / emergency services etc.

Some of our addresses are basically a short sonnet rather than anything that would actually tell you where the house / office actually is.

Eircode looks a bit like UK or Canadian codes, but it's a different concept.

A12 A1B2

A12 = "Routing Key" (broad area. This varies from an area of a city to a large rural area)

A1B2 = quasi-random code that links to an exact delivery point and includes its map coordinates.

There's a fully developed API and all of that stuff to go with it.

So for example if you put in:

If you type in "K67 C3V1 Ireland" into Google maps it should take you directly to Dublin Airport for example.

In an office block with multiple companies or an apartment building, each unit has a unique code.

There are concerns over privacy as it's a unique code referencing every single address in the country and could end up being a bit like a permanent geo-cookie..