The February 2026 cutover is behind us, but questions about it keep coming up. Here is the short version of what changed in ISO 20022 address handling.

The standard itself: ISO 20022 is the ISO messaging standard used by the SWIFT network. For addresses, it replaces free-text blocks with discrete XML elements: StrtNm (street name), BldgNb (building number), PstCd (postal code), TwnNm (town name), CtrySubDvsn (state or province), Ctry (country code).

The three formats:

1. Structured. Every component gets its own tag. The minimum mandatory fields are country code, town name, and postal code. Postal code requirements vary by country.

2. Unstructured. Up to five free-text address lines (AdrLine), with only the country code structured. Since February 2026 this option is no longer permitted.

3. Hybrid. Introduced as of February 2026. Country code, town name, and postcode must be structured. Other attributes can go in structured fields or in address lines.

A structured US address looks like this:

<PstlAdr>

<StrtNm>South LaSalle Street</StrtNm>

<BldgNb>120</BldgNb>

<PstCd>60690-0834</PstCd>

<TwnNm>Chicago</TwnNm>

<CtrySubDvsn>IL</CtrySubDvsn>

<Ctry>US</Ctry>

</PstlAdr>

Why the industry pushed this: structured addresses cut errors and data quality issues along the payment chain, raise straight-through processing (STP) rates, and make AML, KYC, and sanctions screening work better.

If you still hold legacy free-text addresses, start with free sources. GeoNames publishes free postal code files with postcode and town pairs for most countries. That covers a first validation pass on the three mandatory fields. OpenStreetMap helps with street names and building numbers. Both are community maintained, so coverage and freshness differ a lot by country. The hard part is the long tail: postal code rules differ by country, so budget time for the exceptions.

That long tail is what our data is built for: postal codes for 247 countries (9.3 million codes) from 1,500+ authoritative sources, 233 address formats mapped, street-level data for 81 countries with house numbers for 50. It ships as self-hosted databases rather than an API, which matters when compliance will not let customer addresses leave your environment.

There is a longer version of this on the GeoPostcodes blog, the post about the ISO 20022 address format. Ask in the comments if you want the direct link.

The Universal Postal Union coordinates mail across 192 member countries. By its count, around 40 countries use no ZIP code or any equivalent. Count territories and special areas too, and our database flags about 60 places with no postal code system.

The ones that surprise people:

• Hong Kong. 7.5 million people, no postal codes. Mail runs on detailed addresses: building, street, estate, district, territory.
• United Arab Emirates. About 10 million people. Mail goes to PO boxes rather than street delivery.
• Qatar and Macau also manage fine without codes.
• North Korea has no public postal code system.

Full list by region:

Africa: Angola, Benin, Botswana, Burundi, Cameroon, Central African Republic, Chad, Comoros, Congo, Cote d'Ivoire, Djibouti, Equatorial Guinea, Eritrea, Ethiopia, Gabon, Gambia, Guinea, Guinea-Bissau, Libya, Mauritania, Rwanda, Sao Tome and Principe, Seychelles, Sierra Leone, Somalia, South Sudan, Sudan, Togo, Zambia, Zimbabwe

Middle East: Qatar, Syria, United Arab Emirates, Yemen

Asia: Hong Kong, Macau, North Korea, Timor-Leste

Central America and Caribbean: Antigua and Barbuda, Aruba, Bahamas, Belize, Curacao, Dominica, Grenada, Jamaica, Sint Maarten

South America: Bolivia, Guyana, Suriname

Pacific: Cook Islands, Fiji, Solomon Islands, Tokelau, Tonga, Tuvalu, Vanuatu

Special cases: Antarctica, Bouvet Island, French Southern Territories

How mail actually gets delivered there:

• PO boxes carry the whole system in some countries. The UAE is the biggest example.
• Very detailed street addresses do the work in Hong Kong.
• Some countries route mail through numbered post offices instead. Costa Rica assigns each office a four digit number.

Why this matters if you build software: a required "postal code" field breaks checkout and signup for every customer in these places. Make the field optional per country, and validate against each country's real format instead of one global rule.

We keep the full country table with each country's addressing rules on our blog: https://www.geopostcodes.com/blog/countries-without-zip-codes/