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Add the breadth and inertness goals, name the contributor in the audience, and move the handoff's contents into the repo
2026-09-19 13:30:29 +02:00

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Fake-data libraries: data-category inventory

Researched 2026-09-16. Sources: official docs and current master/main/next source trees. "Big four" = @faker-js/faker (JS), Faker (Python), gofakeit (Go), Datafaker (Java). Abbreviations in tables: JS, PY, GO, DF, BG (Bogus), MM (Mimesis), CH (Chance), RB (Ruby faker).

1. Category modules and their generators

Legend: names are the library's own identifiers (camelCase = JS/DF/BG, snake_case = PY/MM/RB, PascalCase = GO). Columns list what each library offers under that module; a — means the module does not exist there.

person

Lib Generators
JS firstName, lastName, middleName, fullName, prefix, suffix, sex, sexType, gender, bio, jobArea, jobDescriptor, jobTitle, jobType, zodiacSign (all name methods take `sex: female
PY first_name/_female/_male/_nonbinary, last_name/_female/_male/_nonbinary, name/_female/_male/_nonbinary, prefix/_female/_male/_nonbinary, suffix/_female/_male/_nonbinary, language_name; separate providers: job (job, job_female, job_male), ssn (ssn; per-locale variants: vat_id, itin, ein, nif, cpf, personnummer …), passport (passport_number, passport_dob, passport_owner), profile (profile → job, company, ssn, residence, current_location, blood_group, website, username, name, sex, address, mail, birthdate; simple_profile)
GO Person (struct), Name, NamePrefix, NameSuffix, FirstName, MiddleName, LastName, Gender, Age, Ethnicity, SSN, EIN, Hobby, SocialMedia, Bio, Contact, Email, Phone, PhoneFormatted, Teams
DF Name: name, nameWithMiddle, fullName, firstName, femaleFirstName, maleFirstName, lastName, prefix, suffix, title, username; Demographic: race, educationalAttainment, demonym, sex, maritalStatus; Gender; Pronouns; BloodType; Mbti; Zodiac; Relationship; Hobby; Mood; Job; Passport; DrivingLicense; IdNumber (valid/invalid per country: US SSN, SE, ZA, SG FIN/UIN, CN, PT NIF, MX, PL PESEL, KR RRN, GE); CPF/CNPJ (BR); Nigeria; Australia
BG Name: FirstName, LastName, FullName, Prefix, Suffix, FindName, JobTitle, JobDescriptor, JobArea, JobType; Person object (Gender, FirstName, LastName, FullName, UserName, Avatar, Email, DateOfBirth, Address, Phone, Website, Company); country extensions: Ssn/Ein (US), Personnummer/Samordningsnummer (SE), Cpr (DK), Henkilotunnus (FI), Fodselsnummer (NO), Pesel/Nip/Regon (PL), CodiceFiscale (IT), Cpf/Cnpj (BR), Sin (CA), Nino (GB), Cnp (RO), NationalNumber (BE), Nif/Nipc (PT)
MM Person: first_name, surname/last_name, patronymic, full_name, name, title, username, password, email, birthdate, gender, gender_symbol, gender_code, sex, height, weight, blood_type, occupation, nationality, university, academic_degree, language, phone_number, telephone, identifier
CH first, last, name, prefix, suffix, gender, age, birthday, ssn, cpf, cf (IT codice fiscale), profession
RB Name (name, name_with_middle, first_name, male_first_name, female_first_name, neutral_first_name, last_name, prefix, suffix, initials), Gender, Demographic, IDNumber (per-country), Job, Relationship, Blood, DrivingLicence, Avatar, ChileRut, SouthAfrica, NationalHealthService

address / location

Lib Generators
JS (location) buildingNumber, cardinalDirection, city, continent, country, countryCode, county, direction, language, latitude, longitude, nearbyGPSCoordinate, ordinalDirection, postalAddress, secondaryAddress, state({abbreviated}), street, streetAddress, timeZone, zipCode({state, format})
PY (address) address, building_number, city, city_suffix, country, country_code, current_country, current_country_code, postcode, street_address, street_name, street_suffix; locale extras e.g. en_US: city_prefix, secondary_address, administrative_unit, state_abbr, zipcode_plus4, postcode_in_state, military_ship/state/apo/dpo; ja_JP: prefecture, city, town, chome, ban, gou, building_name; fr_FR: department, department_name, department_number, region; es_ES: region/autonomous_community; de_DE: city_with_postcode, street_suffix_short/long; en_GB: county; separate geo provider: coordinate, latitude, longitude, latlng, local_latlng(country), location_on_land (real geonames.org places with tz)
GO (address) Address (struct), City, Country, CountryAbr, State, StateAbr, Street, StreetName, StreetNumber, StreetPrefix, StreetSuffix, Unit, Zip, Latitude, LatitudeInRange, Longitude, LongitudeInRange
DF (Address) streetName, streetAddressNumber, streetAddress, secondaryAddress, zipCode, postcode, eircode, zipCodePlus4, zipCodeByState, countyByZipCode, streetSuffix, streetPrefix, citySuffix, cityPrefix, city, cityName, state, stateAbbr, latitude, longitude, latLon, lonLat, timeZone, country, countryCode, buildingNumber, fullAddress, mailBox; plus Country (name, code2/3, capital, currency, flag), Nation (nationality, language, capital, flag), Compass, Mountain, Planet, Space, Locality (locale codes)
BG (Address) ZipCode, City, StreetAddress, CityPrefix, CitySuffix, StreetName, BuildingNumber, StreetSuffix, SecondaryAddress, County, Country, FullAddress, CountryCode, State, StateAbbr, Latitude, Longitude, Direction, CardinalDirection, OrdinalDirection; premium Bogus.Locations: GPS, altitude, depth, geohash
MM (Address) street_number, street_name, street_suffix, secondary_address, address, state/region/province/federal_subject/prefecture (abbr), postal_code/zip_code, country, country_code (A2/A3/numeric), country_emoji_flag, default_country, city, latitude, longitude, coordinates (DMS option), continent, calling_code/isd_code, iata_code, icao_code
CH address, street, city, zip, postal (CA), postcode (GB), state, province, country, areacode, phone, latitude, longitude, altitude, depth, coordinates, geohash, locale
RB city, street_name, street_address, secondary_address, building_number, mail_box, community, zip_code(state_abbreviation:), zip, postcode, time_zone, street_suffix, city_suffix, city_prefix, state, state_abbr, country, country_by_code, country_name_to_code, country_code, country_code_long, latitude, longitude, full_address, full_address_as_hash; Travel: airport, train_station; Locations: australia

company

Lib Generators
JS name, buzzAdjective, buzzNoun, buzzPhrase, buzzVerb, catchPhrase, catchPhraseAdjective, catchPhraseDescriptor, catchPhraseNoun (locale data: adjective, descriptor, noun, legal_entity_type, name_pattern)
PY company, company_suffix, catch_phrase, bs; locale extras (e.g. it_IT/pl_PL company_vat, nl_NL, ru_RU large_company, etc.)
GO Company, CompanySuffix, BS, Blurb, BuzzWord, Slogan, Job, JobDescriptor, JobLevel, JobTitle
DF Company: name, suffix, industry, profession, buzzword, catchPhrase, bs, logo, domainName, url; Business; Brand; IndustrySegments; Marketing; Team; Restaurant; Subscription; Twitter; University; Educator
BG CompanySuffix, CompanyName, CatchPhrase, Bs
MM Finance.company, company_type
CH company, profession
RB Company (name, suffix, industry, profession, type, catch_phrase, buzzword, bs, logo, ein, duns_number, swedish_organisation_number, czech_organisation_number, french_siren/siret, norwegian/australian/spanish/polish/russian/south_african/brazilian ids …), Business, Marketing, IndustrySegments, Team, University, Educator, Restaurant, Subscription, Construction

internet

Lib Generators
JS displayName, domainName, domainSuffix, domainWord, email, exampleEmail, emoji, httpMethod, httpStatusCode, ip, ipv4, ipv6, jwt, jwtAlgorithm, mac, password, port, protocol, url, userAgent, username
PY email, safe_email, free_email, company_email, ascii_* variants, free_email_domain, domain_name, domain_word, safe_domain_name, tld, hostname, dga, http_method, http_status_code, iana_id, image_url, ipv4, ipv4_network_class, ipv4_private, ipv4_public, ipv6, mac_address, nic_handle(s), port_number, ripe_id, slug, uri, uri_extension, uri_page, uri_path, url, user_name; user_agent provider (chrome, firefox, safari, opera, internet_explorer, platform tokens); emoji provider
GO URL, UrlSlug, DomainName, DomainSuffix, IPv4Address, IPv6Address, MacAddress, HTTPStatusCode(Simple), HTTPMethod, HTTPVersion, LogLevel, UserAgent (+Chrome/Firefox/Opera/Safari/API), Username, Password, Emoji (+22 category fns), InputName, Svg
DF Internet: username, emailAddress(name), safeEmailAddress, emailSubject, domainName/Word/Suffix, url, webdomain, image, httpMethod, password(opts), port, macAddress, ipV4Address, privateIpV4Address, publicIpV4Address, ipV4Cidr, ipV6Address, ipV6Cidr, slug, uuidv3/4/7, userAgent, botUserAgent; Http; Domain; Sip; Emoji; SlackEmoji; Credentials; Aws; Azure; Hashing; Fingerprint; Computer; Device; Camera; Drone; Robin
BG Avatar, Email, ExampleEmail, UserName, UserNameUnicode, DomainName, DomainWord, DomainSuffix, Ip, Port, IpAddress, IpEndPoint, Ipv6, UserAgent, Mac, Password, Color, Protocol, Url, UrlWithPath, UrlRootedPath
MM Internet: content_type, dsn, http_status_message/code, http_method, ip_v4/v6 (+object, cidr, with_port, special), cloud_region, asn, mac_address, hostname, url, uri, query_string/parameters, tld, user_agent, port, path, slug, public_dns, http_request/response_headers
CH avatar, color, domain, email, fbid, google_analytics, hashtag, ip, ipv6, klout, tld, twitter, url
RB Internet (email, username, password, domain_name, ip_v4/v6, mac_address, url, slug, user_agent, uuid, bot_user_agent …), Internet::HTTP, Omniauth, Stripe, X (Twitter), Avatar, Placeholdit, LoremFlickr

finance / payment / bank

Lib Generators
JS accountName, accountNumber, amount, bic, bitcoinAddress, creditCardCVV, creditCardIssuer, creditCardNumber, currency, currencyCode, currencyName, currencyNumericCode, currencySymbol, ethereumAddress, iban, litecoinAddress, pin, routingNumber, transactionDescription, transactionType
PY bank: aba, bank, bank_country, bban, iban, swift, swift8, swift11; credit_card: credit_card_number, credit_card_provider, credit_card_expire, credit_card_security_code, credit_card_full; currency: currency, currency_code, currency_name, currency_symbol, cryptocurrency(_code/_name), pricetag
GO Price, CreditCard, CreditCardCvv, CreditCardExp, CreditCardNumber, CreditCardType, Currency, CurrencyLong, CurrencyShort, AchRouting, AchAccount, BitcoinAddress, BitcoinPrivateKey, BankName, BankType, Cusip, Isin
DF Finance: creditCard(type), bic, iban(country), ibanSupportedCountries, usRoutingNumber; Money: currency, currencyCode, currencyNumericCode, currencySymbol; Currency; Stock; FinancialTerms; CryptoCoin; Coin; Business
BG Account, AccountName, Amount, TransactionType, Currency, CreditCardNumber, CreditCardCvv, BitcoinAddress, EthereumAddress, RoutingNumber, Bic, Iban; GB SortCode, VatNumber
MM Finance: bank, currency_iso_code, currency_symbol, cryptocurrency_iso_code/_symbol, price, price_in_btc, stock_ticker, stock_name, stock_exchange; Payment: cid, bitcoin_address, ethereum_address, credit_card_network/number/expiration_date, cvv, credit_card_owner
CH cc, cc_type, currency, currency_pair, dollar, euro, exp, exp_month, exp_year
RB Finance (credit_card, vat_number, ticker, stock_market), Bank (name, swift_bic, iban, account_number, routing_number, bsb_number), Currency, Crypto, Blockchain (bitcoin, ethereum, tezos, aeternity), Invoice, Stripe, Coin

commerce / product

Lib Generators
JS department, isbn, price, product, productAdjective, productDescription, productMaterial, productName, upc
PY barcode: ean, ean8, ean13, localized_ean*; isbn: isbn10, isbn13; sbn; (no product/commerce provider in core; community Ecommerce provider)
GO Product (struct), ProductName, ProductDescription, ProductCategory, ProductFeature, ProductMaterial, ProductUPC, ProductAudience, ProductDimension, ProductUseCase, ProductBenefit, ProductSuffix, ProductISBN
DF Commerce: department, productName, material, brand, vendor, price(min,max), promotionCode; Barcode; Code (isbn10/13, gtin8/13, ean, asin, imei); Appliance; GarmentSize; Size; Tire; House; ElectricalComponents
BG Department, Price, Categories, ProductName, Color, Product, ProductAdjective, ProductMaterial, Ean8, Ean13
MM Code: locale_code, issn, isbn, ean, imei, pin
CH —
RB Commerce (color, department, material, product_name, price, promotion_code, brand, vendor), Barcode, Code (isbn, ean, asin, imei, npi, nric, rut, sin), Appliance, Device, Camera, House

vehicle / transport

Lib Generators
JS bicycle, color, fuel, manufacturer, model, type, vehicle, vin, vrm; airline: aircraftType, airline, airplane, airport, flightNumber, recordLocator, seat
PY automotive: license_plate, vin (per-locale plate formats)
GO Car (struct), CarMaker, CarModel, CarType, CarFuelType, CarTransmissionType; Airline*: AircraftType, Airplane, Airport, AirportIATA, FlightNumber, RecordLocator, Seat
DF Vehicle: vin, manufacturer, make, model(make), makeAndModel, style, color, upholstery(+Color/Fabric), transmission, driveType, fuelType, carType, engine, carOptions, standardSpecs, doors, licensePlate(state); Aviation; Transport; DrivingLicense
BG Vin, Manufacturer, Model, Type, Fuel; GbRegistrationPlate
MM Transport: manufacturer, car, airplane, vehicle_registration_code(locale)
CH —
RB Vehicle (vin, manufacture, make, model, make_and_model, style, color, transmission, drive_type, fuel_type, car_type, engine, car_options, standard_specs, doors, door, year, mileage, license_plate, singapore_license_plate, version), Drone, Travel::Airport, Travel::TrainStation

lorem / text / words

Lib Generators
JS lorem: lines, paragraph(s), sentence(s), slug, text, word(s); word: adjective, adverb, conjunction, interjection, noun, preposition, sample, verb, words; hacker: abbreviation, adjective, ingverb, noun, phrase, verb; string: alpha, alphanumeric, binary, fromCharacters, hexadecimal, nanoid, numeric, octal, sample, symbol, ulid, uuid
PY lorem: word(s), sentence(s), paragraph(s), text(s), get_words_list; misc: password, md5, sha1, sha256, binary, boolean, null_boolean, csv/dsv/psv/tsv, fixed_width, json, json_bytes, image, tar, zip, uuid4
GO Word families: Noun* (Common/Concrete/Abstract/Collective*/Countable/Uncountable/Proper/Determiner), Verb* (Action/Linking/Helping/Transitive/Intransitive), Adverb* (Manner/Degree/Place/Time*/Frequency*), Preposition* (Simple/Double/Compound), Adjective* (8 kinds), Pronoun* (8 kinds), Connective* (6 kinds), Word, Interjection, Sentence, Paragraph, LoremIpsum{Word,Sentence,Paragraph}, Question, Quote, Phrase{,Noun,Verb,Adverb,Preposition}, Comment; Hacker*, Hipster{Word,Sentence,Paragraph}; Letter(N), Digit(N), Vowel, Lexify, Numerify, RandomString, ShuffleStrings
DF Lorem (word(s), sentence(s), paragraph(s), characters, fixedString, maxLengthSentence, supplemental), Text (character, upper/lowercase, text with symbol rules), Verb, Word, Hacker, Hipster, Shakespeare, Yoda, Joke, ChuckNorris, Matz, NatoPhoneticAlphabet, FunnyName, Marketing
BG Lorem: Word(s), Letter, Sentence(s), Paragraph(s), Text, Lines, Slug; Hacker: Abbreviation, Adjective, Noun, Verb, IngVerb, Phrase; Rant: Review(s)
MM Text: alphabet, level, text, sentence, title, words, word, quote, color, hex_color, rgb_color, answer, emoji
CH paragraph, sentence, syllable, word, character, letter, string
RB Lorem (word(s), character(s), sentence(s), paragraph(s), question(s), paragraph_by_chars, multibyte), Markdown, Hipster, Hacker, Adjective, Verbs, Quote, Quotes::Shakespeare/Chiquito/Rajnikanth, ChuckNorris, Emotion, Source (code snippets), Html, Json, Types, Alphanumeric, String, Boolean, NatoPhoneticAlphabet

date / time

Lib Generators
JS anytime, between, betweens, birthdate({mode: age
PY date_time: date, date_time, date_object, time, time_object, date_between(_dates), date_time_between(dates), date_this_century/decade/month/year, date_time_this*, date_time_ad, date_of_birth(minimum_age, maximum_age), future_date(time), past_date(time), iso8601, unix_time, time_delta, time_series, timezone, pytimezone, am_pm, century, year, month, month_name, day_of_month, day_of_week
GO Date, PastDate, FutureDate, DateRange, NanoSecond, Second, Minute, Hour, Month, MonthString, Day, WeekDay, Year, TimeZone, TimeZoneAbv, TimeZoneFull, TimeZoneOffset, TimeZoneRegion
DF DateAndTime: future, past, between, birthday, birthdayLocalDate, duration, period; Time; TimeAndDate
BG Past, PastOffset, Soon, SoonOffset, Future, FutureOffset, Between, BetweenOffset, Recent, RecentOffset, Timespan, Month, Weekday
MM Datetime: date, datetime, time, timestamp, formatted_*, week_date, day_of_week, month, year, day_of_month, timezone, gmt_offset, periodicity, future/past_date(time), duration, bulk_create_datetimes
CH ampm, date, hammertime, hour, millisecond, minute, month, second, timestamp, timezone, weekday, year
RB Date (between, between_except, forward, backward, birthday, in_date_period, on_day_of_week_between), Time (between, between_dates, forward, backward)

phone

Lib Generators
JS number({style: human
PY phone_number, country_calling_code, msisdn (per-locale formats)
GO Phone, PhoneFormatted
DF PhoneNumber: cellPhone, cellPhoneInternational, phoneNumber, phoneNumberInternational, phoneNumberNational, extension, subscriberNumber
BG PhoneNumber, PhoneNumberFormat
MM Person.phone_number/telephone (mask), Address.calling_code
CH phone, areacode
RB PhoneNumber (phone_number, cell_phone, country_code, phone_number_with_country_code, cell_phone_with_country_code, cell_phone_in_e164, area_code, exchange_code, subscriber_number, extension)

science / medical

Lib Generators
JS chemicalElement, unit; medical locale data (en only)
PY — (community: Healthcare, Biology, Geoscience, Scientific)
GO —
DF Science: element, elementSymbol, unit, scientist, tool, quark, leptons, bosons; Medical, Medication, Disease, MedicalProcedure, CareProvider, Observation, BloodType, Measurement, Weather, Planet, Space, Mountain, Cannabis, LargeLanguageModel
BG premium Bogus.Healthcare
MM Science: rna_sequence, dna_sequence
CH —
RB Science (element, element_symbol, element_state, element_subcategory, scientist, modifier, tool), Space, Measurement, Cannabis, Medical (NationalHealthService)

music / animal / food / books / entertainment

Lib Generators
JS music: album, artist, genre, songName; animal: bear, bird, cat, cetacean, cow, crocodilia, dog, fish, horse, insect, lion, petName, rabbit, rodent, snake, type; food: adjective, description, dish, ethnicCategory, fruit, ingredient, meat, spice, vegetable; book: author, format, genre, publisher, series, title
PY — (core has none; community Music, Sci Fi)
GO Song, SongName, SongArtist, SongGenre; PetName, Animal, AnimalType, FarmAnimal, Cat, Dog, Bird; Fruit, Vegetable, Breakfast, Lunch, Dinner, Snack, Dessert, Drink; Beer{Alcohol,Blg,Hop,Ibu,Malt,Name,Style,Yeast}; Book, BookTitle, BookAuthor, BookGenre; Movie, MovieName, MovieGenre; Celebrity{Actor,Business,Sport}; Minecraft (18 fns)
DF Music: instrument, key, chord, genre; RockBand; Artist; Kpop; Hololive; Animal: name, scientificName, genus, species; Cat, Dog, Horse; Food: ingredient, allergen, spice, dish, fruit, vegetable, sushi, measurement; Apple, Beer, Cheese, Coffee, Dessert, IceCream, Tea; Book, Movie, Show, OscarMovie; ~75 entertainment franchises, ~31 videogames, 9 sports
BG Music (premium Hollywood: movies, TV, actors)
MM Food: vegetable, fruit, dish, spices, drink
CH animal (with type), tv, radio, rpg, dice
RB Music (+11 bands), Creature (animal, bird, cat, dog, horse), Food, Beer, Coffee, Tea, Dessert, Book, Books (4 series), Movie/Movies (17), TvShows (39), Games (26), JapaneseMedia (10), Sports (6), Fantasy::Tolkien, Religion::Bible, Superhero, DcComics, Kpop, Ancient, GreekPhilosophers, Cosmere

color / image / system / database / misc

Lib Generators
JS color: cmyk, colorByCSSColorSpace, cssSupportedFunction, cssSupportedSpace, hsl, human, hwb, lab, lch, rgb, space; image: avatar, avatarGitHub, dataUri, personPortrait, url, urlLoremFlickr, urlPicsumPhotos; system: commonFileExt/Name/Type, cron, directoryPath, fileExt/Name/Path/Type, mimeType, networkInterface, semver; database: collation, column, engine, mongodbObjectId, type; git: branch, commitDate, commitEntry, commitMessage, commitSha; number: bigInt, binary, float, hex, int, octal, romanNumeral; datatype.boolean; science.unit
PY color: color, color_name, safe_color_name, hex_color, safe_hex_color, rgb_color, rgb_css_color, color_hsl/hsv/rgb/rgb_float; file: file_extension, file_name, file_path, mime_type, unix_device, unix_partition; python: pybool, pydecimal, pydict, pyfloat, pyint, pyiterable, pylist, pyobject, pyset, pystr, pystr_format, pystruct, pytuple, enum; doi; emoji; user_agent
GO Color, HexColor, RGBColor, HSLColor, SafeColor, NiceColors; Image, ImageJpeg, ImagePng; CSV, JSON, XML, SQL, FileExtension, FileMimeType, Template, Markdown, EmailText, FixedWidth; ID, UUID; Error* (9 kinds); AppName, AppVersion, AppAuthor; Language, LanguageAbbreviation, LanguageBCP, ProgrammingLanguage; School; Gamertag, Dice; Bool, Weighted, FlipACoin; Number/Int*/Uint*/Float* ranges
DF Color, Image, File, App, ProgrammingLanguage, LanguageCode, Number, Bool, Unique, Options, Photography, Military, OlympicSport, Weather, Construction, Community, Chiquito … (263 providers total)
BG Images: DataUri, PicsumUrl, PlaceholderUrl, LoremFlickrUrl; System: FileName, DirectoryPath, FilePath, CommonFileName, MimeType, CommonFileType/Ext, FileType, FileExt, Semver, Version, Exception, AndroidId, ApplePushToken, BlackBerryPin; Database: Column, Type, Collation, Engine; Randomizer (numbers, chars, Guid, Hash, Enum, WeightedRandom, Shuffle …)
MM Hardware: resolution, screen_size, cpu, cpu_frequency, generation, cpu_codename, ram_type, ram_size, ssd_or_hdd, graphics, manufacturer, phone_model; Development: software_license, calver, version, stage, programming_language, os, boolean, system_quality_attribute; File, BinaryFile, Path, Cryptographic (uuid, hash, token, mnemonic), Numeric, Choice
CH bool, falsy, floating, integer, natural, prime, hex, guid, hash, coin, dice, normal (Gaussian), n, unique, weighted, android_id, apple_token, bb_pin, wp7_anid, wp8_anid2
RB Color, File, Computer, Device, ProgrammingLanguage, App, Number, Boolean, Hash/Crypto, Json, Html, Markdown, Military, Compass, Coin, Mountain, Nation, Space, Time, Types, Slack Emoji, Vulnerability identifier

Module presence summary:

Module JS PY GO DF BG MM CH RB
person x x x x x x x x
address x x x x x x x x
company x x x x x (finance) x x
internet x x x x x x x x
finance x x x x x x x x
commerce/product x barcode only x x x code only — x
vehicle x plate/vin x x x x — x
airline x — x x — iata/icao — x
lorem/words x x x x x x x x
date x x x x x x x x
phone x x x x x x x x
science x — — x — dna — x
medical data only — — x premium — — x
music x — x x — — — x
animal x — x x — — x x
food x — x x — x — x
book x isbn x x — — — x
color x x x x x text x x
image x x x x x binaryfile avatar x
system/file x x x x x x — x
database x — sql — x dsn — —
git x — — — — — — —
hacker/hipster x — x x x — — x
national IDs — ssn per locale SSN/EIN IdNumber ext. pkgs identifier ssn/cpf/cf IDNumber
pop-culture — — minecraft, movie ~110 premium — tv, rpg ~85
hardware — — — Computer/Device — x — Computer/Device
weather/space — — — x — — — Space

2. Locale coverage and address data structure

Locale counts

Lib Locales Structure
JS 77 dirs under src/locales (incl. base, en_BORK, en_AU_ocker) One dir per locale, one file per module per key (en/location/city_name.ts). Fallback chain per Faker instance: [de_CH, de, en, base]; first locale that defines a key wins. base holds locale-independent data (ISO codes, time zones). A key may be explicitly null to mean "not applicable" (e.g. no zip codes for HK) so it does not fall through to en. https://fakerjs.dev/guide/localization.html
PY 126 locale codes listed; per provider: address 67, person 86, ssn 56 Python subclasses per providers/<provider>/<locale>/__init__.py overriding tuples/formats of the base. Missing provider for a locale falls back to en_US. Coverage is uneven (am_ET = phone only). Multi-locale Faker(['it_IT','en_US']) with optional weights. https://faker.readthedocs.io/en/master/locales.html
GO 1 (English/US). No locale API; Language/LanguageBCP only emit language codes Static Go maps in data/*.go. Open issue #352 "generate data for specific country/language" unanswered. https://github.com/brianvoe/gofakeit/issues/352
DF 127 yml files in src/main/resources (incl. 49 country-only files like _SE.yml and 78 language(-region) files); README says "60+" One YAML per locale (sv-SE.yml) under sv-SE: faker: address: …; en/ split into 264 per-provider files. Locale chain de_CH → de → en, key-by-key. Values are templates #{Name.first_name}. Custom yml via faker.addPath(locale, path). Country file (_SE.yml) layered over language file.
BG 50 (data/*.locale.json; README says 46) Verbatim copy of faker.js (v5-era) locale JSON, merged with data_extend/*.locale.json by a gulp task, shipped as BSON. Falls back to en. https://github.com/bchavez/Bogus/wiki/Creating-Locales
MM 47 (53 dirs incl. global, int, bin, template) Per locale six JSON files: address, datetime, finance, food, person, text. Everything else (internet, payment, code, hardware…) is locale-independent.
CH 1 (en; postal CA and postcode GB formats exist, locale() only returns codes) Data inline in chance.js.
RB 58 yml files ("over 40" in README) One YAML per locale lib/locales/<code>.yml (en split into en/*.yml), I18n gem, key-level fallback to en.

Address data: real or synthetic, and correlation

Lib Cities Street names Postcodes Hierarchy / correlation
JS en: real list city_name (~1000 US cities) is one of 5 city_patterns; the other 4 are {prefix} {firstName}{suffix} style synthetic. de: 327 real cities; sv: no city_name, pattern-only synthetic. Varies per locale. en: street_pattern = {firstName} {street_suffix} / {lastName} … (synthetic); de: 1800 real street names (from one NRW region). Format masks (#####, #####-####). en_US has postcode_by_state so zipCode({state:'CA'}) gives a state-prefixed range. None between city↔state↔zip. county is a flat list. timeZone is per-locale. nearbyGPSCoordinate is the only "correlated" geo function. Issue #983: en_CA returned US cities; PR #2141 added real cities for ZA locales — real-city coverage is locale-by-locale volunteer work.
PY Per locale. en_US/en_GB: synthetic ({city_prefix} {first_name}{city_suffix}). de_DE 400+ real, sv_SE 45 real, pl_PL real, ja_JP real prefectures/cities/towns, es_ES real provinces + regions. en_US: {first_name} {street_suffix}; sv_SE: prefix+suffix ("Björkgatan"); de_DE: synthetic name+Straße; pl_PL: real street-name pools. Masks. en_US: postcode_in_state with real per-state numeric ranges (still random within range, "not correlated with cities"). fr_FR: postcode built from a real department number (correlated to department, not to city). en_GB: real outward-area letters but random assembly. sv_SE: %####. No country→state→city hierarchy anywhere; ja_JP has prefecture–city pairs in data but methods pick independently. geo.local_latlng(country) returns real geonames places (name, lat, lon, country, tz) — the only real, correlated location record in the library. address_formats are weighted (25.0 standard vs 1.0 military).
GO Real list of major US cities Real-looking suffix lists; StreetName is a pool ##### mask None: Address() picks city, state, zip independently; lat/lon are uniform random on the globe, not near the city. Open issue #196 "Better address" unanswered.
DF en: city formats are all synthetic (#{city_prefix} #{Name.first_name}#{city_suffix}); cityName draws from a separate real list. sv-SE: real city_name list; de: synthetic. en: #{Name.first_name} #{street_suffix}; de: real street_root list combined randomly. Masks; en-US postcode_by_state (350##), zipCodeByState, countyByZipCode (en-US only), eircode (IE). None by default. Issue #1551 (Locale.CHINA yields "福建省南京市") open as "proposal". Issue #1477 unresolved directive for city names in some locales.
BG Whatever faker.js v5 had per locale (en: synthetic patterns only — real city_name list postdates the copy) synthetic Masks; en_US postcode_by_state None. Issue #481 "Invalid Zip Codes (US)" open. Issue #342 "City returns people's names" (side effect of {firstName} patterns).
MM Real lists per locale (en: real US cities; sv: real municipalities incl. small towns) en: real San Francisco street names; sv: real Swedish street names postal_code_fmt mask per locale; sv has none state (name+ISO 3166-2 abbr) real, but no link to city or postcode; default_country tied to locale. Open question #1584 on choosing default city per locale.
CH Synthetic (3-syllable word) Synthetic word + real suffix Real-format masks None
RB en: synthetic patterns (city_with_state exists but is city, state random) ; some locales have real lists {first_name} {street_suffix} #####; zip_code(state_abbreviation:) uses per-state pattern (900##); doc says "may not be an actual state zip" full_address_as_hash returns fields but does not correlate them. Issue #2881 (state vs state_abbr mismatch, country vs country_code mismatch) open; #1958 asked for geocodable city+zip; #2899 fake zips closed "not planned".

Which libraries correlate any address fields at all: Python Faker (fr_FR postcode↔department, en_US zip↔state range, geo.local_latlng real records), faker-js/Datafaker/Bogus/Ruby (zip↔state range only, en_US), Mimesis (locale↔country only). None ships a country→region→city→postcode hierarchy or city↔lat/lon.

Other localized fields (what varies per locale)

  • JS: sv overrides color, commerce, company, date, internet, location, person, phone_number, team; en defines 24 modules; base 9. So finance/vehicle/animal/food/science are effectively English-only.
  • PY: per-locale providers exist for address, automotive (plate formats), bank (IBAN/BBAN/SWIFT by country), company (VAT IDs), currency, date_time (month/day names), internet (TLDs, free email domains, user-name formats), job, lorem (word lists), person, phone_number, ssn (national IDs with check digits), passport, color, barcode (EAN prefixes), misc.
  • DF de.yml overrides: address, company, compass, creature, lorem, hipster, name, color, commerce, book, university, chuck_norris, space, music, games, food, simpsons, dr_who, vehicle. Country files (_SE.yml) mainly phone_number and address formats.
  • MM: only address, datetime, finance, food, person, text are localized.

Name weighting

Lib Weighted by frequency?
PY Yes, default use_weighting=True. en_US: ~500 female + ~500 male first names weighted from SSA decade tables, ~1000 surnames weighted by US Census; sv_SE: ~1000/1000/1000 weighted from Skatteverket/ISOF. Plus weighted address_formats, random_element(OrderedDict).
JS No. Plain lists (en: ~650 female, ~550 male, ~400 generic first names). helpers.weightedArrayElement exists for user data only.
GO No. ~1500 first, ~500 last, plain slices. Weighted(options, weights) for user data.
DF No. en: ~1200 male, ~4400 female first names, ~1000 last, unweighted.
BG No (faker.js data); Randomizer.WeightedRandom for user data.
MM No. en: ~4000 female, ~3000 male, ~2500 surnames, unweighted.
CH No; weighted() helper only.
RB No.

3. Common complaints (issues and posts)

4. Notable and unusual features

  • Datafaker — expression language #{Name.first_name}, #{regexify '[a-z]{4,10}'}, #{numerify '##'}, #{bothify}, #{letterify}, #{templatify}, #{examplify}, #{options.option 'A','B'}, #{csv …}, #{json …}, method calls with args (#{date.birthday 'yy DDD'}); nested resolution (https://www.datafaker.net/documentation/expressions/). Schema.of(field(...), compositeField(...)) with transformers to CSV, JSON, YAML, XML, TOML, SQL (batch inserts, Postgres/Oracle/Spark dialects, ARRAY/MULTISET/ROW), @FakeForSchema POJO population (https://www.datafaker.net/documentation/schemas/). faker.collection(...).len(3,5), infinite stream(), faker.unique(), sequences, custom yml via addPath. 263 providers, the largest pop-culture catalogue (≈110 franchises/games).
  • gofakeit — Go text/template based Template(), Markdown(), EmailText(), FixedWidth(); Generate("{firstname} {regex:[a-z]{5}} {randomstring:[a,b]}") mini-language; Struct(&v) fill via fake:"{city}", fakesize, format tags; Slice, Map, Regex; CSV/JSON/XML/SQL output; AddFuncLookup registers custom functions with parameter metadata (used by its CLI and HTTP server); Weighted(); word families split by grammatical role (46 Noun/Verb/Adjective/Pronoun/Connective sub-kinds); Error* generators; Minecraft.
  • Mimesis — Field/Fieldset/Schema builder (Field(locale)("person.full_name"), keyed lookups with key= post-processors like maybe, romanize), Schema(schema=lambda: {...}, iterations=n) exporting to JSON/CSV/pickle, relational data with SchemaRef foreign keys, custom field handlers, factory-boy integration, fastest Python generator; locale = six JSON files; ISO country codes in A2/A3/numeric; DMS coordinates.
  • Bogus — Faker<T>().RuleFor(x => x.Prop, f => …) fluent rules with StrictMode, CustomInstantiator, FinishWith, Rules(), Ignore, rule sets; local vs global seeding, UseDateTimeReference; Bogus.Distributions.Gaussian; country ID extension packages; premium Locations/Healthcare/Hollywood/Text packages; Roslyn analyzer; AutoBogus auto-fills any class.
  • faker-js — locale fallback stack with explicit null = "not applicable"; mergeLocales; helpers.fake('{{person.firstName}}') template; helpers.fromRegExp, weightedArrayElement, multiple, uniqueArray, mustache; pluggable Randomizer (32/53-bit Mersenne), Distributors (uniform, exponential); date.birthdate({mode:'age'|'year'}); location.nearbyGPSCoordinate; git module; person.bio; typed per-locale definition files generated by script.
  • Python Faker — use_weighting (frequency-weighted names/formats from census data); OrderedDict weighted random_element; fake.unique, fake.optional; multi-locale instance with weights; geo.local_latlng real geonames records; misc file/archive/CSV/JSON/image generators; pystr_format; pytest fixture; CLI; 24 community providers (healthcare, market data, observability, airtravel, education, security, pyspark …).
  • Chance — weighted, normal (Gaussian), unique, n, mixin, set (override data), pick/pickone/pickset; mobile IDs (android_id, apple_token, bb_pin, wp7/8 anid); geohash/altitude/depth.
  • Ruby faker — full_address_as_hash, Faker::Config.locale, Faker::UniqueGenerator, Faker::Config.random; Types generator for random Ruby types; company registration numbers for ~12 countries; deep pop-culture catalogue (~85 themed generators).
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