The api can be used with all country codes in Europe.
List of country codes:

Albania: AL
Andorra: AD
Austria: AT
Belarus: BY
Belgium: BE
Bosnia and Herzegovina: BA
Bulgaria: BG
Croatia: HR
Cyprus: CY
Czech Republic: CZ
Denmark: DK
Estonia: EE
Finland: FI
France: FR
Germany: DE
Greece: GR
Hungary: HU
Iceland: IS
Ireland: IE
Italy: IT
Kosovo: XK
Latvia: LV
Liechtenstein: LI
Lithuania: LT
Luxembourg: LU
Malta: MT
Moldova: MD
Monaco: MC
Montenegro: ME
Netherlands: NL
North Macedonia: MK
Norway: NO
Poland: PL
Portugal: PT
Romania: RO
Russia: RU
San Marino: SM
Serbia: RS
Slovakia: SK
Slovenia: SI
Spain: ES
Sweden: SE
Switzerland: CH
Ukraine: UA
United Kingdom: GB
Vatican City: VA