Docs › Countries API › Data sources
The Countries API's dataset is stitched together from authoritative public registries, multilateral bodies, and well-maintained open-data projects. Static fields are cross-checked against ISO and UN baselines weekly; other fields are synced every 4 hours by reconciling multiple upstream feeds against each other before a value is published. Where each field comes from is below.
License-vetted at the source. Everything the Countries API exposes is drawn from
public-domain government registries (UN, ISO, IANA, CIA Factbook, NIST, NGA), CC0-released open-data
projects (Wikidata, Natural Earth), or other openly-licensed open-data projects whose
terms we've cleared for downstream commercial use. We do the licensing diligence so you don't have
to. The values you receive are clean to use in any product, including ones you sell, with no
upstream attribution chain to maintain. (Use of the REST Countries API itself is governed by
the Terms.)
Standards & registries
The International Organization for Standardization's registry of
country codes, maintained continuously since 1974. The de facto reference for country
identification across software, finance, logistics, and government, anywhere a country needs an
unambiguous identifier.
Updates
codes.alpha_2, codes.alpha_3, codes.ccn3,
classification.iso_status
ISO's three-letter language code registry, the broadest of the
language standards, covering ~7,000 living, extinct, ancient, constructed, and special-purpose
languages. Maintained by SIL International.
Updates
names.native, names.translations, demonyms,
languages
ISO's three-letter currency code registry plus minor-unit
precision (cents, fils, qirsh). The same standard your bank, SWIFT, and every payments processor
uses.
Updates
currencies
The Internet Assigned Numbers Authority's authoritative list of
country-code top-level domains, the same registry your DNS resolver consults at the root.
Updates
tlds
The "tz" / "Olson" database, the canonical record of historical
and current time-zone rules every operating system relies on. Captures every DST transition,
leap second, and zone rename.
Updates
timezones
The International Telecommunication Union's recommendation
defining the international public telephone numbering plan, including country and global-service
calling codes (the +1 / +44 / +81 system).
Updates
calling_codes
The UN agency coordinating postal policy across 192 member
countries since 1874. Maintains canonical postal-code formats and the S42 international
addressing standard.
Updates
postal_code.format, postal_code.regex
The Common Locale Data Repository, the largest open repository of
locale-formatting data, maintained by the Unicode Consortium. Powers number, date, calendar,
currency, and plural-rule formatting in every major operating system, browser, and programming
language.
Updates
number_format.decimal_separator, number_format.thousands_separator,
date.start_of_week
The US National Institute of Standards and Technology's two-letter
country-code standard, used historically across US federal agencies. Withdrawn in 2008 in favor
of ISO 3166-1, but still encountered in legacy government and intelligence-community
datasets.
Updates
codes.fips
The Geopolitical Entities and Codes (GEC, formerly FIPS 10-4)
standard maintained by the NGA, the current US-government answer to country identification,
used in mapping and intelligence systems.
Updates
codes.gec
Statistics & official data
The UN body responsible for the M49 standard (country and area
codes for statistical use), plus the canonical lists of UN member states, observer states,
sovereign entities, and the standard regional / sub-regional groupings used across UN
reporting.
Updates
classification.sovereign, region, subregion,
continents
The team behind the World Population Prospects, the UN's biennial
demographic projections covering every country since 1950. The reference baseline for population
data across nearly every cross-country research project.
Updates
population
The World Bank's open-data platform, exposing thousands of
indicators across countries and decades: population, surface area, GDP, Gini coefficients,
education and health metrics. Free, well-documented, with stable APIs.
Updates
population (dynamic), area.kilometers (dynamic),
area.miles (dynamic), economy.gini_coefficient (static)
The CIA's open reference encyclopedia covering geography,
government, economy, and people for every country. Public-domain (US Government work) and
updated continuously.
Updates
government_type, capitals, landlocked,
borders
Sport & cultural codes
The IOC's three-letter codes used at the Olympic Games and across
Olympic-affiliated sports federations. Mostly aligned with ISO alpha-3 but with a handful of
historical differences (RSA for South Africa, SUI for Switzerland).
Updates
codes.cioc
The Fédération Internationale de Football Association's
three-letter codes used in international football, qualifying competitions, and the World Cup.
Similar shape to the IOC list but with its own legacy variations (KSA for Saudi Arabia).
Updates
codes.fifa
Geographic data
A public-domain map dataset purpose-built for cartography,
maintained by Tom Patterson and a community of cartographers. Country shapes at three levels of
detail, plus centroid coordinates that don't drift outside a country's actual territory.
Updates
coordinates.lat, coordinates.lng
An open-source geographical database covering every country and 11
million populated places. Capital coordinates, alternate names in dozens of languages, time-zone
associations. CC BY-licensed and continuously maintained.
Updates
capitals, names.alternates
The community-maintained open map of the world. Used here for
capital-city geocoding cross-checks and for the per-country OpenStreetMap link itself.
Updates
links.open_street_maps, capitals (verification)
Reference & encyclopedic
The Wikimedia Foundation's structured-data sister project to
Wikipedia. CC0-licensed, machine-queryable via SPARQL, with rich cross-language identifiers.
REST Countries' primary structured-data source for translations, demonyms, and head-of-state data;
Wikidata's structure beats Wikipedia's free text any day for programmatic ingest.
Updates
names.alternates, names.translations, demonyms,
leaders, links.wikipedia
SIL International's reference catalogue of the world's living
languages: what's spoken where, by how many people, with what level of vitality. The reference
for cross-country language data.
Updates
languages
Mozilla's authoritative list of domain suffixes browsers and
applications should treat as TLDs. Used to validate cookie scopes, build trust boundaries, and
confirm what the IANA root zone actually publishes.
Updates
tlds (validation)
Flag assets
The Wikimedia Foundation's media repository, the largest
collection of public-domain and free-licensed media in the world. Country flags as canonical SVG
sources, kept up-to-date with current designs.
Updates
flag.url_svg, flag.url_png
The body behind the Unicode Standard. Defines the
regional-indicator code points that combine to form country flag emoji, plus the broader Emoji
Standard.
Updates
flag.emoji, flag.unicode, flag.html_entity
Membership organizations
For each memberships.* boolean we cross-reference the published roster on
the organization's own site, treating it as the source of truth.
Founded in 1945, headquartered in New York. The canonical source
for UN membership and observer status; REST Countries tracks the official member-states list
directly.
Updates
memberships.un, classification.un_member,
classification.un_observer
The political and economic union of 27 European member states.
Sits separately from the related but distinct Eurozone (countries using the euro) and Schengen
Area (the passport-free zone).
Updates
memberships.eu
The passport-free zone. Includes some non-EU countries
(Switzerland, Norway, Iceland, Liechtenstein) and excludes some EU countries. Roster maintained
by the European Commission's DG Home Affairs.
Updates
memberships.schengen
The 32-member North Atlantic Treaty Organization, headquartered in
Brussels. Member roster maintained at nato.int.
Updates
memberships.nato
The 38-member Organisation for Economic Co-operation and
Development, headquartered in Paris.
Updates
memberships.oecd
The 56-member Commonwealth of Nations, headquartered in London.
Member list maintained by the Commonwealth Secretariat.
Updates
memberships.commonwealth
The forum of seven major industrialized democracies (Canada,
France, Germany, Italy, Japan, UK, US, plus the EU as a non-enumerated participant). No
permanent secretariat; presidency rotates annually.
Updates
memberships.g7
The forum of 19 major economies plus the European Union and the
African Union, hosted by the country holding the rotating presidency.
Updates
memberships.g20
Originally Brazil, Russia, India, China, and South Africa; expanded
post-2024 to include additional members. REST Countries tracks the current roster announced by the BRICS
chair.
Updates
memberships.brics
The Organization of the Petroleum Exporting Countries, whose member states coordinate
petroleum policies through the Vienna-based organization.
Updates
memberships.opec
The 55-member union of African states, headquartered in Addis
Ababa. Successor to the Organisation of African Unity.
Updates
memberships.african_union
The 10-member Association of Southeast Asian Nations, secretariat
in Jakarta.
Updates
memberships.asean
Spotted something off?
If a value looks wrong against any of the sources above, send it our way. Include the country, the property path, what the API returned, and what you believe the correct value is (with a source link if you have one). We'll verify against upstream and ship a correction or roll the offending feed off our reconciliation list.