Fun facts about Dutch addresses

I've got some project where correct addresses are important. And while doing that project, I've found out some fun things about dutch addresses...

I think most developers know the "Falsehoods programmers believe about addresses" post. If you never seen it, it's a worth-reading list! This one goes about lots of addresses around the world.

This post is only about Dutch addresses, because there are some strange addresses out there in the Netherlands!
And as-the-nerd-that-I-am, I've spent some time to write the things I've learned about addresses down in some blog post :-).

"The default ones" 

I think all people familiar with Dutch addresses, know the basic formattings;

Programmeerstraat 13
Developstad  9999XZ

OR

Programmeerstraat 94 A (and B, C, D - Z)
Developstad 9999XZ

This is mostly used for buildings that are later separated into multiple properties.
The letter is called a "Houseletter/Huisletter (Dutch)".

For example this can happen when there first was "Programmeerstraat 94", that was 1 building.
Later the building will get separated in different offices or studio's.
Then the different offices/studio's, will get A, B, C, D... etc.

Most people are familiar with this options.
But with the alphabet, you have 26 options when an address needs to get spitted up . But sometimes you need more options...

So housenumber additions exist!

As said above, when a housenumber has some letter after it, it's called the "Houseletter".

But there are also housenumber additions, mostly just a extra NUMBER!
So there are addresses like;

Programmeerstraat 94 G 30
Developstad 9999XZ

OR

Programmeerstraat 4 G 20
Developstad 9999XZ

Where 30 and 20 are the house number additions...

But an address does not need to have a houseletter, to have a housenumber

So this can also be a valid address:

Programmeerstraat 3 1
Developstad 9999XZ

Yes, 3 1. Where 3 is the housenumber, and 1 is the housenumber addition...

I know that there are addresses where a housenumber + zipcode, will have more then 150 different house number additions...

Dutch streets can have numbers in it, also as last part of the street

In the Netherlands there are squares named "Plein '40-'45" (referring to the second world war). There are also more street names/squares with numbers in it, also at the end...

So the following address can be valid;

Plein '40-'45 935
Developerstad 9999XZ

And with the knowledge of Housenumber additions and houseletters, the following addresses can also be valid in theory:

Plein '40-'45 34 G 30
Developerstad 9999XZ

OR

Plein '40-'45 50 3
Developerstad 9999X

"Randstad 20", "Randstad 21", "Randstad 22" (This are streets... without housenumbers)

And some other nice finding, in Almere you got Randstad with some number as streetnames...

Yes. I don't know the how/why about this... Maybe something to investigate when I have some spare time over in my life?
But the area seems to be named Randstad, and the streets in the area are just named Randstad with some number after it. So the following addresses could be valid...

Randstad 20 21 A 22
Developerstad 9999XZ

OR

Randstad 22 23 34
Developerstad 9999XZ

Right now I could not find actual addresses with that formats... 

So if you need to work with (Dutch) addresses, be careful...

With this knowledge, think about your address fields... There are lot of options in addresses, and you may not know about all the options you need yet...

Think about the UI/UX, and think about fault inputs from end-users...
Make it easy to enter, but keep in mind that there are lots of options... And also don't forget that users often forget to fill in fields (also because of auto-fill options from that browsers, that don't always work well with house number additions).

Also think about storing addresses. Saving house numbers as Integer is a bad idea...
Also think about splitting parts, and making fields required...
I would suggest, to not require anything about addresses. Because, you never know what weird variation someone needs to enter someday...

Want to know everything about dutch addresses? There is a NEN standard...

There is a "NEN standard" named NEN 5825:2002 nl (Dutch, I don't know if there is an English translation).
I don't needed this for my project, but if you want more information about dutch addresses you can buy this NEN standard to read more information about addresses.

Special thanks to members of the PHPNL Slack User Group that send me some more "strange" addresses 

Disclaimer; At time of writing this blog, I've checked the addresses for non-existing. So all addresses are just examples.
If some address is will exist someday later, this is just a coincidence..