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The Username API categorizes usernames into 19 distinct categories to help you identify reserved usernames, brands, celebrities, locations, and more. Some categories include metadata like country codes or language codes to provide additional context.

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Category Reference

CategoryDescriptionMetadata
otherCatch-all category for usernames that don’t fit into other specific categoriesNone
dictionaryCommon dictionary words that may be reserved to prevent generic usernameslang (language code)
cityCity names from around the world that are reserved to prevent location-based impersonationcountry (ISO country code)
countryCountry names that are reserved to prevent impersonation of nationsNone
regionRegional names (states, provinces, territories) that are reservedNone
brandTrademarked brand names and company trademarks that are protectedNone
first_nameCommon first names that are reserved to prevent impersonationNone
last_nameCommon last names that are reserved to prevent impersonationNone
systemSystem-reserved usernames (e.g., “admin”, “root”, “system”)None
restrictedUsernames that are explicitly restricted due to offensive or inappropriate contentNone
productProduct names and service names that are reservedNone
celebrityNames of celebrities, public figures, and notable individualscountry (ISO country code)
governmentGovernment entities, departments, and official government accountscountry (ISO country code)
agencyGovernment agencies and regulatory bodiescountry (ISO country code)
institutionEducational institutions, hospitals, and other major institutionscountry (ISO country code)
eventMajor events, conferences, and notable occasions that are reservedNone
companyCompany names and business entities that are reservedcountry (ISO country code)
placeNotable places, landmarks, and locations that don’t fit city/country categoriescountry (ISO country code)
organizationNon-profit organizations, NGOs, and other organizational entitiesNone

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Metadata

Some categories include metadata to provide additional context:
  • lang: Language code (e.g., “en”, “es”, “fr”) used for dictionary words
  • country: ISO country code (e.g., “US”, “GB”, “DE”) used for location-based categories
When a category includes metadata, the API response will include the metadata object with the relevant fields. Categories without metadata will have null or no metadata field in the response.

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Usage Example

When checking a username, the API returns all applicable categories: 
{
  "username": "berlin",
  "isReserved": true,
  "isDeleted": false,
  "categories": [
    {
      "category": "city",
      "metadata": {
        "country": "DE"
      }
    }
  ]
}
This indicates that “berlin” is reserved as a city (Berlin, Germany).