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Published: Jan 22, 2019 License: MIT Imports: 13 Imported by: 14




Struct Data Fake Generator

Faker will generate you a fake data based on your Struct.

Build Status codecov Go Report Card License GoDoc



You can file an Issue. See documentation in Godoc

Getting Started

go get -u github.com/bxcodec/faker


With Tag

Supported tag:

Internet :

  • Email
  • Mac address
  • Domain name
  • URL
  • UserName
  • IP Address (IPv4, IPv6 )
  • Password

Payment :

  • Credit Card Number

Address :

  • Latitude and Longitude

Phone :

  • Phone number
  • Toll free phone number
  • E164PhoneNumber

Person :

  • Title male
  • Title female
  • FirstName
  • FirstName male
  • FirstName female
  • LastName
  • Name

DateTime :

  • UnixTime
  • Date
  • Time
  • MonthName
  • Year
  • DayOfWeek
  • DayOfMonth
  • Timestamp
  • Century
  • TimeZone
  • TimePeriod

Lorem :

  • Word
  • Sentence
  • Paragraph

Price :

  • Currency
  • Amount
  • Amount with Currency


  • UUID Digit (32 bytes)
  • UUID Hyphenated (36 bytes)

Skip :

  • -

package main

import (


// SomeStruct ...
type SomeStruct struct {
	Latitude           float32 `faker:"lat"`
	Longitude          float32 `faker:"long"`
	CreditCardNumber   string  `faker:"cc_number"`
	CreditCardType     string  `faker:"cc_type"`
	Email              string  `faker:"email"`
	IPV4               string  `faker:"ipv4"`
	IPV6               string  `faker:"ipv6"`
	Password           string  `faker:"password"`
	PhoneNumber        string  `faker:"phone_number"`
	MacAddress         string  `faker:"mac_address"`
	URL                string  `faker:"url"`
	UserName           string  `faker:"username"`
	ToolFreeNumber     string  `faker:"tool_free_number"`
	E164PhoneNumber    string  `faker:"e_164_phone_number"`
	TitleMale          string  `faker:"title_male"`
	TitleFemale        string  `faker:"title_female"`
	FirstName          string  `faker:"first_name"`
	FirstNameMale      string  `faker:"first_name_male"`
	FirstNameFemale    string  `faker:"first_name_female"`
	LastName           string  `faker:"last_name"`
	Name               string  `faker:"name"`
	UnixTime           int64   `faker:"unix_time"`
	Date               string  `faker:"date"`
	Time               string  `faker:"time"`
	MonthName          string  `faker:"month_name"`
	Year               string  `faker:"year"`
	DayOfWeek          string  `faker:"day_of_week"`
	DayOfMonth         string  `faker:"day_of_month"`
	Timestamp          string  `faker:"timestamp"`
	Century            string  `faker:"century"`
	TimeZone           string  `faker:"timezone"`
	TimePeriod         string  `faker:"time_period"`
	Word               string  `faker:"word"`
	Sentence           string  `faker:"sentence"`
	Paragraph          string  `faker:"paragraph"`
	Currency           string  `faker:"currency"`
	Amount             float64 `faker:"amount"`
	AmountWithCurrency string  `faker:"amount_with_currency"`
	UUIDHypenated	   string  `faker:"uuid_hyphenated"`
	UUID	           string  `faker:"uuid_digit"`
	Skip		   string  `faker:"-"`

func main() {

	a := SomeStruct{}
	err := faker.FakeData(&a)
	if err != nil {
	fmt.Printf("%+v", a)
		Output  :
			Latitude: 81.12195
			Longitude: -84.38158
			CreditCardType: American Express
			CreditCardNumber: 373641309057568
			Email: mJBJtbv@OSAaT.ru
			IPV6: 975c:fb2c:2133:fbdd:beda:282e:1e0a:ec7d
			Password: dfJdyHGuVkHBgnHLQQgpINApynzexnRpgIKBpiIjpTPOmNyMFb
			PhoneNumber: 792-153-4861
			MacAddress: cd:65:e1:d4:76:c6
			URL: https://www.oEuqqAY.org/QgqfOhd
			UserName: lVxELHS
			ToolFreeNumber: (777) 831-964572
			E164PhoneNumber: +724891571063
			TitleMale: Mr.
			TitleFemale: Queen
			FirstName: Whitney
			FirstNameMale: Kenny
			FirstNameFemale: Jana
			LastName: Rohan
			Name: Miss Casandra Kiehn
			UnixTime: 1197930901
			Date: 1982-02-27
			Time: 03:10:25
			MonthName: February
			Year: 1996
			DayOfWeek: Sunday
			DayOfMonth: 20
			Timestamp: 1973-06-21 14:50:46
			Century: IV
			TimeZone: Canada/Eastern
			TimePeriod: AM
			Word: nesciunt
			Sentence: Consequatur perferendis aut sit voluptatem accusantium.
			Paragraph: Aut consequatur sit perferendis accusantium voluptatem. Accusantium perferendis consequatur voluptatem sit aut. Aut sit accusantium consequatur voluptatem perferendis. Perferendis voluptatem aut accusantium consequatur sit.
			Currency: IRR,
			Amount: 88.990000,
			AmountWithCurrency: XBB 49257.100000,
			UUIDHypenated: 8f8e4463-9560-4a38-9b0c-ef24481e4e27,
			UUID: 90ea6479fd0e4940af741f0a87596b73,

Custom Generator Provider

You can also add your own generator function to your own defined tags. See example below

type Gondoruwo struct {
	Name       string
	Locatadata int

type Sample struct {
	ID                 int64     `faker:"customIdFaker"`
	Gondoruwo          Gondoruwo `faker:"gondoruwo"`
	Danger             string    `faker:"danger"`

func CustomGenerator() {
	faker.AddProvider("customIdFaker", func(v reflect.Value) (interface{}, error) {
		 return int64(43), nil
	faker.AddProvider("danger", func(v reflect.Value) (interface{}, error) {
		return "danger-ranger", nil

	faker.AddProvider("gondoruwo", func(v reflect.Value) (interface{}, error) {
		obj := Gondoruwo{
			Name:       "Power",
			Locatadata: 324,
		return obj, nil

func main() { 
	var sample Sample
	fmt.Printf("%+v", sample)


{ID:43 Gondoruwo:{Name:Power Locatadata:324} Danger:danger-ranger}

Without Tag

You also can use faker to generate your structs data randomly without any tag. And it will fill the data based on its data-type.

package main

import (


type SomeStruct struct {
	Int      int
	Int8     int8
	Int16    int16
	Int32    int32
	Int64    int64
	String   string
	Bool     bool
	SString  []string
	SInt     []int
	SInt8    []int8
	SInt16   []int16
	SInt32   []int32
	SInt64   []int64
	SFloat32 []float32
	SFloat64 []float64
	SBool    []bool
	Struct   AStruct
type AStruct struct {
	Number        int64
	Height        int64
	AnotherStruct BStruct

type BStruct struct {
	Image string

func main() {

	a := SomeStruct{}
	err := faker.FakeData(&a)
	if err != nil {
	fmt.Printf("%+v", a)
		    SString:[bzYwplRGUAXPwatnpVMWSYjep zmeuJVGHHgmIsuyWmLJnDmbTI FqtejCwoDyMBWatoykIzorCJZ]
		    SInt:[11661230973193 626062851427 12674621422454 5566279673347]
		    SInt8:[12 2 58 22 11 66 5 88]
		    SInt16:[29295225 8411281 69902706328]
		    SInt32:[60525685140 2733640366211 278043484637 5167734561481]
		    SInt64:[81684520429188374184 9917955420365482658170 996818723778286568 163646873275501565]
		    SFloat32:[0.556428 0.7692596 0.6779895 0.29171365 0.95445055]
		    SFloat64:[0.44829454895586585 0.5495675898536803 0.6584538253883265]
		    SBool:[true false true false true true false]


Example to use Faker


Bench To Generate Fake Data

Without Tag
BenchmarkFakerDataNOTTagged-4             500000              3049 ns/op             488 B/op         20 allocs/op
Using Tag
 BenchmarkFakerDataTagged-4                100000             17470 ns/op             380 B/op         26 allocs/op

The Struct Field must PUBLIC.
Support Only For :

  • int int8 int16 int32 int64
  • []int []int8 []int16 []int32 []int64
  • bool []bool
  • string []string
  • float32 float64 []float32 []float64
  • Nested Struct Field
  • time.Time []time.Time


Unfortunately this library has some limitation

  • Not support for private field. Just make sure your field's struct is public. If not, it will throw panic error. You can avoid panic using tag skip faker:"-" in the private field.
  • Not support for interface{} data type. How we can generate if we don't know what is the data type?
  • Not support for map[interface{}]interface{}, map[any_type]interface{}, map[interface{}]any_type. Still, it's about interface. We can't give you something if we don't know what really you want.
  • Not fully support for custom type, but a few custom type already supported, still investigating how to do this in the correct ways. For now, if you use faker, it's safer not to use any custom type to avoid panic.


To contrib on this project, you can make a PR or just an issue.





View Source
const (
	BaseDate   = "2006-01-02"
	Time       = "15:04:05"
	Month      = "January"
	Year       = "2006"
	Day        = "Monday"
	DayOfMonth = "_2"
	TimePeriod = "PM"

These example values must use the reference time "Mon Jan 2 15:04:05 MST 2006" as described at https://gobyexample.com/time-formatting-parsing

View Source
const (
	ID                 = "uuid_digit"
	HyphenatedID       = "uuid_hyphenated"
	Email              = "email"
	MacAddress         = "mac_address"
	DomainName         = "domain_name"
	UserName           = "username"
	URL                = "url"
	IPV4               = "ipv4"
	IPV6               = "ipv6"
	PASSWORD           = "password"
	LATITUDE           = "lat"
	LONGITUDE          = "long"
	CreditCardNumber   = "cc_number"
	CreditCardType     = "cc_type"
	PhoneNumber        = "phone_number"
	TollFreeNumber     = "tool_free_number"
	E164PhoneNumber    = "e_164_phone_number"
	TitleMale          = "title_male"
	TitleFemale        = "title_female"
	FirstName          = "first_name"
	FirstNameMale      = "first_name_male"
	FirstNameFemale    = "first_name_female"
	LastName           = "last_name"
	NAME               = "name"
	UnixTime           = "unix_time"
	DATE               = "date"
	TIME               = "time"
	MonthName          = "month_name"
	YEAR               = "year"
	DayOfWeek          = "day_of_week"
	DayOfMonthTag      = "day_of_month"
	TIMESTAMP          = "timestamp"
	CENTURY            = "century"
	TIMEZONE           = "timezone"
	TimePeriodTag      = "time_period"
	WORD               = "word"
	SENTENCE           = "sentence"
	PARAGRAPH          = "paragraph"
	Currency           = "currency"
	Amount             = "amount"
	AmountWithCurrency = "amount_with_currency"
	SKIP               = "-"

Supported tags


View Source
var (
	ErrUnsupportedKindPtr  = "Unsupported kind: %s Change Without using * (pointer) in Field of %s"
	ErrUnsupportedKind     = "Unsupported kind: %s"
	ErrValueNotPtr         = "Not a pointer value"
	ErrTagNotSupported     = "Tag unsupported"
	ErrTagAlreadyExists    = "Tag exists"
	ErrMoreArguments       = "Passed more arguments than is possible : (%d)"
	ErrNotSupportedPointer = "Use sample:=new(%s)\n faker.FakeData(sample) instead"

Generic Error Messages for tags

ErrUnsupportedKindPtr: Error when get fake from ptr
ErrUnsupportedKind: Error on passing unsupported kind
ErrValueNotPtr: Error when value is not pointer
ErrTagNotSupported: Error when tag is not supported
ErrTagAlreadyExists: Error when tag exists and call AddProvider
ErrMoreArguments: Error on passing more arguments
ErrNotSupportedPointer: Error when passing unsupported pointer


func AddProvider

func AddProvider(tag string, provider TaggedFunction) error

AddProvider extend faker with tag to generate fake data with specified custom algoritm

func FakeData

func FakeData(a interface{}) error

FakeData is the main function. Will generate a fake data based on your struct. You can use this for automation testing, or anything that need automated data. You don't need to Create your own data for your testing.

func RandomInt

func RandomInt(parameters ...int) (p []int, err error)

RandomInt Get three parameters , only first mandatory and the rest are optional

If only set one parameter :  This means the minimum number of digits and the total number
If only set two parameters : First this is min digit and second max digit and the total number the difference between them
If only three parameters: the third argument set Max count Digit

func RandomUnixTime

func RandomUnixTime() int64

RandomUnixTime is a helper function returning random Unix time

func SetAddress

func SetAddress(net Addresser)

SetAddress sets custom Address

func SetDataFaker

func SetDataFaker(d DataFaker)

SetDataFaker sets Custom data in lorem

func SetDateTimer

func SetDateTimer(d DateTimer)

SetDateTimer sets custom date time

func SetDowser

func SetDowser(d Dowser)

SetDowser sets custom Dowsers of Person names

func SetNetwork

func SetNetwork(net Networker)

SetNetwork sets custom Network

func SetPayment

func SetPayment(p Render)

SetPayment set custom Network

func SetPhoner

func SetPhoner(p Phoner)

SetPhoner sets custom Phoner

func SetPrice

func SetPrice(p Money)

SetPrice sets custom Money


type Address

type Address struct{}

Address struct

func (Address) Latitude

func (i Address) Latitude(v reflect.Value) (interface{}, error)

Latitude sets latitude of the address

func (Address) Longitude

func (i Address) Longitude(v reflect.Value) (interface{}, error)

Longitude sets longitude of the address

type Addresser

type Addresser interface {
	Latitude(v reflect.Value) (interface{}, error)
	Longitude(v reflect.Value) (interface{}, error)

Addresser is logical layer for Address

func GetAddress

func GetAddress() Addresser

GetAddress returns a new Addresser interface of Address

type DataFaker

type DataFaker interface {
	Word(v reflect.Value) (interface{}, error)
	Sentence(v reflect.Value) (interface{}, error)
	Paragraph(v reflect.Value) (interface{}, error)

DataFaker generates randomized Words, Sentences and Paragraphs

func GetLorem

func GetLorem() DataFaker

GetLorem returns a new DataFaker interface of Lorem struct

type DateTime

type DateTime struct {

DateTime struct

func (DateTime) Century

func (d DateTime) Century(v reflect.Value) (interface{}, error)

Century returns a random century

func (DateTime) Date

func (d DateTime) Date(v reflect.Value) (interface{}, error)

Date formats DateTime using example BaseDate const

func (DateTime) DayOfMonth

func (d DateTime) DayOfMonth(v reflect.Value) (interface{}, error)

DayOfMonth formats DateTime using example DayOfMonth const

func (DateTime) DayOfWeek

func (d DateTime) DayOfWeek(v reflect.Value) (interface{}, error)

DayOfWeek formats DateTime using example Day const

func (DateTime) MonthName

func (d DateTime) MonthName(v reflect.Value) (interface{}, error)

MonthName formats DateTime using example Month const

func (DateTime) Time

func (d DateTime) Time(v reflect.Value) (interface{}, error)

Time formats DateTime using example Time const

func (DateTime) TimePeriod

func (d DateTime) TimePeriod(v reflect.Value) (interface{}, error)

TimePeriod formats DateTime using example TimePeriod const

func (DateTime) TimeZone

func (d DateTime) TimeZone(v reflect.Value) (interface{}, error)

TimeZone returns a random timezone

func (DateTime) Timestamp

func (d DateTime) Timestamp(v reflect.Value) (interface{}, error)

Timestamp formats DateTime using example Timestamp const

func (DateTime) UnixTime

func (d DateTime) UnixTime(v reflect.Value) (interface{}, error)

UnixTime get unix time

func (DateTime) Year

func (d DateTime) Year(v reflect.Value) (interface{}, error)

Year formats DateTime using example Year const

type DateTimer

type DateTimer interface {
	UnixTime(v reflect.Value) (interface{}, error)
	Date(v reflect.Value) (interface{}, error)
	Time(v reflect.Value) (interface{}, error)
	MonthName(v reflect.Value) (interface{}, error)
	Year(v reflect.Value) (interface{}, error)
	DayOfWeek(v reflect.Value) (interface{}, error)
	DayOfMonth(v reflect.Value) (interface{}, error)
	Timestamp(v reflect.Value) (interface{}, error)
	Century(v reflect.Value) (interface{}, error)
	TimeZone(v reflect.Value) (interface{}, error)
	TimePeriod(v reflect.Value) (interface{}, error)

A DateTimer contains random Time generators, returning time string in certain particular format

func GetDateTimer

func GetDateTimer() DateTimer

GetDateTimer returns a new DateTimer interface of DateTime

type Dowser

type Dowser interface {
	TitleMale(v reflect.Value) (interface{}, error)
	TitleFeMale(v reflect.Value) (interface{}, error)
	FirstName(v reflect.Value) (interface{}, error)
	FirstNameMale(v reflect.Value) (interface{}, error)
	FirstNameFemale(v reflect.Value) (interface{}, error)
	LastName(v reflect.Value) (interface{}, error)
	Name(v reflect.Value) (interface{}, error)

Dowser provides interfaces to generate random logical Names with their initials

func GetPerson

func GetPerson() Dowser

GetPerson returns a new Dowser interface of Person struct

type Identifier

type Identifier interface {
	Digit(v reflect.Value) (interface{}, error)
	Hyphenated(v reflect.Value) (interface{}, error)

Identifier ...

func GetIdentifier

func GetIdentifier() Identifier

GetIdentifier returns a new Identifier

type Internet

type Internet struct{}

Internet struct

func (Internet) DomainName

func (internet Internet) DomainName(v reflect.Value) (interface{}, error)

DomainName generates random domain name

func (Internet) Email

func (internet Internet) Email(v reflect.Value) (interface{}, error)

Email generates random email id

func (Internet) IPv4

func (internet Internet) IPv4(v reflect.Value) (interface{}, error)

IPv4 generates random IPv4 address

func (Internet) IPv6

func (internet Internet) IPv6(v reflect.Value) (interface{}, error)

IPv6 generates random IPv6 address

func (Internet) MacAddress

func (internet Internet) MacAddress(v reflect.Value) (interface{}, error)

MacAddress generates random MacAddress

func (Internet) Password

func (internet Internet) Password(v reflect.Value) (interface{}, error)

Password returns a hashed password

func (Internet) URL

func (internet Internet) URL(v reflect.Value) (interface{}, error)

URL generates random URL standardised in urlFormats const

func (Internet) UserName

func (internet Internet) UserName(v reflect.Value) (interface{}, error)

UserName generates random username

type Lorem

type Lorem struct {

Lorem struct

func (Lorem) Paragraph

func (l Lorem) Paragraph(v reflect.Value) (interface{}, error)

Paragraph returns a series of sentences as a paragraph using the wordList const

func (Lorem) Sentence

func (l Lorem) Sentence(v reflect.Value) (interface{}, error)

Sentence returns a sentence using the wordList const

func (Lorem) Word

func (l Lorem) Word(v reflect.Value) (interface{}, error)

Word returns a word from the wordList const

type Money

type Money interface {
	Currency(v reflect.Value) (interface{}, error)
	Amount(v reflect.Value) (interface{}, error)
	AmountWithCurrency(v reflect.Value) (interface{}, error)

Money provides an interface to generate a custom price with or without a random currency code

func GetPrice

func GetPrice() Money

GetPrice returns a new Money interface of Price struct

type Networker

type Networker interface {
	Email(v reflect.Value) (interface{}, error)
	MacAddress(v reflect.Value) (interface{}, error)
	DomainName(v reflect.Value) (interface{}, error)
	URL(v reflect.Value) (interface{}, error)
	UserName(v reflect.Value) (interface{}, error)
	IPv4(v reflect.Value) (interface{}, error)
	IPv6(v reflect.Value) (interface{}, error)
	Password(v reflect.Value) (interface{}, error)

Networker is logical layer for Internet

func GetNetworker

func GetNetworker() Networker

GetNetworker returns a new Networker interface of Internet

type Payment

type Payment struct{}

Payment struct

func (Payment) CreditCardNumber

func (p Payment) CreditCardNumber(v reflect.Value) (interface{}, error)

CreditCardNumber generated credit card number according to the card number rules

func (Payment) CreditCardType

func (p Payment) CreditCardType(v reflect.Value) (interface{}, error)

CreditCardType returns one of the following credit values: VISA, MasterCard, American Express and Discover

type Person

type Person struct {

Person struct

func (Person) FirstName

func (p Person) FirstName(v reflect.Value) (interface{}, error)

FirstName retuns first names

func (Person) FirstNameFemale

func (p Person) FirstNameFemale(v reflect.Value) (interface{}, error)

FirstNameFemale retuns first names for females

func (Person) FirstNameMale

func (p Person) FirstNameMale(v reflect.Value) (interface{}, error)

FirstNameMale retuns first names for males

func (Person) LastName

func (p Person) LastName(v reflect.Value) (interface{}, error)

LastName returns last name

func (Person) Name

func (p Person) Name(v reflect.Value) (interface{}, error)

Name returns a random name

func (Person) TitleFeMale

func (p Person) TitleFeMale(v reflect.Value) (interface{}, error)

TitleFeMale generates random titles for females

func (Person) TitleMale

func (p Person) TitleMale(v reflect.Value) (interface{}, error)

TitleMale generates random titles for males

type Phone

type Phone struct {

Phone struct

func (Phone) E164PhoneNumber

func (p Phone) E164PhoneNumber(v reflect.Value) (interface{}, error)

E164PhoneNumber generates phone numbers of type: "+27113456789"

func (Phone) PhoneNumber

func (p Phone) PhoneNumber(v reflect.Value) (interface{}, error)

PhoneNumber generates phone numbers of type: "201-886-0269"

func (Phone) TollFreePhoneNumber

func (p Phone) TollFreePhoneNumber(v reflect.Value) (interface{}, error)

TollFreePhoneNumber generates phone numbers of type: "(888) 937-7238"

type Phoner

type Phoner interface {
	PhoneNumber(v reflect.Value) (interface{}, error)
	TollFreePhoneNumber(v reflect.Value) (interface{}, error)
	E164PhoneNumber(v reflect.Value) (interface{}, error)

Phoner serves overall tele-phonic contact generator

func GetPhoner

func GetPhoner() Phoner

GetPhoner serves as a constructor for Phoner interface

type Price

type Price struct {

Price struct

func (Price) Amount

func (p Price) Amount(v reflect.Value) (interface{}, error)

Amount returns a random floating price amount with a random precision of [1,2] up to (10**8 - 1)

func (Price) AmountWithCurrency

func (p Price) AmountWithCurrency(v reflect.Value) (interface{}, error)

AmountWithCurrency combines both price and currency together

func (Price) Currency

func (p Price) Currency(v reflect.Value) (interface{}, error)

Currency returns a random currency from currencies

type Render

type Render interface {
	CreditCardType(v reflect.Value) (interface{}, error)
	CreditCardNumber(v reflect.Value) (interface{}, error)

Render contains Whole Random Credit Card Generators with their types

func GetPayment

func GetPayment() Render

GetPayment returns a new Render interface of Payment struct

type TaggedFunction

type TaggedFunction func(v reflect.Value) (interface{}, error)

TaggedFunction ...

type UUID

type UUID struct{}

UUID struct

func (UUID) Digit

func (i UUID) Digit(v reflect.Value) (interface{}, error)

Digit returns a 32 bytes UUID

func (UUID) Hyphenated

func (i UUID) Hyphenated(v reflect.Value) (interface{}, error)

Hyphenated returns a 36 byte hyphenated UUID


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