Generate Fake Data For Mock API Response

Imagine that you want to prototype an app with realistic-looking data, but the backend APIs are not there yet. That's where Beeceptor comes in. With Beeceptor, you have access to a powerful template engine that uses Handlebars' syntax. You can easily generate fake data that looks and feels realistic, without the hassle of dealing with messy code.

Fake data helpers

Beeceptor uses popular Faker's comparable syntax. It becomes a breeze to generate small/large data using a mocked response template. You can use pretty much all the attributes from Faker namespaces.

Enabling faker template

By default, template engine is off. You need to explicitly mark a rule to enable usage of Handlebars template to generate fake data.

The faker Syntax

Beeceptor defines faker as a Handlebars template helper.

Faker attributes are grouped into namespaces. E.g. datatype, address, company, etc. To generate faked value for given attribute, prefix the attribute with its namespace. Refer below examples and values generated.

Syntax: {{faker 'namespace.attribute'}}

Sample Syntax	Generated value
{{faker 'string.uuid'}}	52375efe-cf9e-44f5-adb2-65c1631bfcea
{{faker 'location.country'}}	Spain
{{faker 'finance.currencyCode'}}	USD
{{faker 'hacker.phrase'}}	The AI hard drive is down, index the 1080p panel so we can override the COM firewall!
{{faker 'lorem.paragraph'}}	Omnis perspiciatis provident error. Est possimus voluptates. Illo nam et excepturi blanditiis quae rerum et amet accusantium. Mollitia temporibus temporibus ea fugiat quia in possimus et. Ut provident est debitis perspiciatis ipsa non mollitia magnam quis. Et quod dolorum et non

You can use the context menu in the template editor to insert dynamic expressions for test data generation. Start typing {{ followed by a keyword, and the menu will show a list of matching options. Selecting an item will insert the full syntax in place, which you can edit as needed.

Refer the section below to view complete list of supported attributes.

Example using mocking template

You can mix and match any of the Faker attributes to build a rich response. Consider the following example for GET /users API or model.

Mocking Template: A mocking template to build user objects.

[
    { 
        "id" : "{{faker 'string.uuid'}}",
        "name": "{{faker 'person.firstName'}} {{faker 'person.lastName'}}" ,
        "address": "{{faker 'location.streetAddress'}}",
        "country": "{{faker 'location.country'}}",
        "phone": "{{faker 'phone.number'}}",
        "profileImage": "{{faker 'image.url'}}",
    },
    { 
        "id" : "{{faker 'string.uuid'}}",
        "name": "{{faker 'person.firstName'}} {{faker 'person.lastName'}}" ,
        "address": "{{faker 'location.streetAddress'}}",
        "country": "{{faker 'location.country'}}",
        "phone": "{{faker 'phone.number'}}",
        "profileImage": "{{faker 'image.url'}}",
    }
]

Response: This will generate below output:

[
    { 
        "id" : "cbe55c5d-36fa-4f05-9557-fcd4966187f4",
        "name": "Dillon Davis" ,
        "address": "613 Dickinson Run",
        "country": "Tanzania",
        "phone": "886.292.3509 x0831",
        "profileImage": "http://placeimg.com/640/480/business",
    },
    { 
        "id" : "36df51a8-8d4c-4d70-8818-d77b9f6bf215",
        "name": "Dannie Hackett" ,
        "address": "8449 Brenna Alley",
        "country": "Central African Republic",
        "phone": "(786) 895-4923",
        "profileImage": "http://placeimg.com/640/480/business",
    }
]

Datatype classes

Use the following common constructs to generate random datatype values, string, uuid, etc.

number.float
number.int
datatype.boolean
string.string
string.hexadecimal
string.uuid

Number

Generate various number formats:

number.bigInt
number.binary
number.float
number.hex
number.int
number.octal

Whole number examples

Syntax	Sample output
{{faker 'number.int' '100000'}}	Generates a random number less than 100,000. 34746
{{faker 'number.int' '{min:500, max:600}'}}	Generates a random number in the range of 500 to 600. 523
{{faker 'number.bigInt'}}	Generates a large random number. 686544021836087

Floating point examples

Syntax	Sample Output
{{faker 'number.float'}}	Returns a random floating-point number, by default between 0.0 and 1.0. 0.7571638825
{{faker 'number.float' '100'}}	Returns a random floating-point number up to 100. 10.17630657
{{faker 'number.float' '{fractionDigits:2}'}}	Returns a random number between 0 and 1 with two decimal places. 0.39
{{faker 'number.float' '{min: 100, max: 1000, multipleOf:0.25}'}}	Returns a random number between 100 and 1000, multiple of 0.25. 516.75

String

Generate various string formats:

string.alpha
string.alphanumeric
string.binary
string.fromCharacters
string.hexadecimal
string.nanoid
string.numeric
string.octal
string.sample
string.symbol
string.uuid

Date

date.past
date.future
date.between
date.recent
date.month
date.weekday

Date Formatting - Syntax and Examples

When working with mock APIs, you might need to generate date values in a particular format. Beeceptor supports a range of date formatting options, enabling you to customize both standard and non-standard date outputs to suit your requirements.

You can generate date values using the following syntax with for a variety of formats. Below are some common examples:

Use Case	Syntax Example	Output Example
Future Date in ISO Format	{{faker 'date.future' 'iso'}}	2024-03-22T14:12:53.789+00:00
Recent Date in UTC Format	{{faker 'date.recent' 'utc'}}	2024-10-03T10:22:45Z
Future Timestamp in Milliseconds	{{faker 'date.future' 'timestamp'}}	1734963456000
Past Date in US Format	{{faker 'date.past' 'us'}}	12/15/2021
Custom Date Format (ISO with Milliseconds)	{{faker 'date.past' 'YYYY-MM-DDTHH:mm:ss.SSSZ'}}	2022-04-10T05:32:21.456+00:00
Time Only in Custom Format	{{faker 'date.past' 'HH:mm:ss.SSSZ'}}	11:45:32.123+00:00
Past Date in European Format	{{faker 'date.past' 'eu'}}	15/12/2021
Full Human-readable Date Format	{{faker 'date.past' 'full'}}	Wednesday, April 10, 2022 5:32:21 AM
Compact Date Format for Unique ID	{{faker 'date.past' 'compact'}}	20220410053221
SQL Compatible Format	{{faker 'date.past' 'sql'}}	2022-04-10 05:32:21

The examples above illustrate how to specify different formats using the faker function to meet your specific requirements.

Shorthand Date Formatting Options

Beeceptor supports several shorthand notations for date formatting. The table below shows these standard notations and their corresponding formats:

Shorthand	Format Specification	Description
iso	YYYY-MM-DDTHH:mm:ss.SSSZ	ISO 8601 format with milliseconds; useful for international standards.
iso8601	YYYY-MM-DDTHH:mm:ss.SSSZ	Another alias for ISO 8601, commonly used in APIs.
rfc2822	ddd, DD MMM YYYY HH:mm:ss ZZ	RFC 2822 format, often used for email headers.
rfc3339	YYYY-MM-DDTHH:mm:ssZ	RFC 3339 format, suitable for machine-readable timestamps.
w3c	YYYY-MM-DDTHH:mm:ssZ	W3C standard for date and time on the web.
unix	X	Unix epoch time in seconds, useful for Unix-based systems.
timestamp	x	Unix epoch time in milliseconds; great for precise timestamps.
short	YYYY-MM-DD	Short date format, ideal for compact displays of date only.
long	YYYY-MM-DD HH:mm:ss	Long format with time, typically used for detailed logs.
full	dddd, MMMM D, YYYY h:mm:ss A	Full, human-readable date format; great for user interfaces.
compact	YYYYMMDDHHmmss	Compact representation with no separators; useful for IDs.
utc	YYYY-MM-DD[T]HH:mm:ss[Z]	UTC format, recommended for data that needs universal reference.
sql	YYYY-MM-DD HH:mm:ss	SQL-compatible format for database entries.
us	MM/DD/YYYY	US date format, typically used in US-based applications.
eu	DD/MM/YYYY	European date format, commonly used across Europe.

Text classes

Lorem

Some blah blah... text and paragraphs.

lorem.word
lorem.words
lorem.sentence
lorem.slug
lorem.sentences
lorem.paragraph
lorem.paragraphs
lorem.text
lorem.lines

Word

Generate various word types:

word.adjective
word.adverb
word.conjunction
word.interjection
word.noun
word.preposition
word.pronoun
word.verb
word.words

Additional supported classes

Person Names

Generate first/last name, titles, job type, etc.

person.bio
person.firstName
person.fullName
person.gender
person.jobArea
person.jobDescriptor
person.jobTitle
person.jobType
person.lastName
person.middleName
person.prefix
person.sex
person.sexType
person.suffix
person.zodiacSign

Airline

Generate airline-related data:

airline.aircraftType
airline.airline
airline.airplane
airline.airport
airline.flightNumber
airline.recordLocator
airline.seat

Animal

Generate animal-related data:

animal.bear
animal.bird
animal.cat
animal.cetacean
animal.cow
animal.crocodilia
animal.dog
animal.fish
animal.horse
animal.insect
animal.lion
animal.rabbit
animal.rodent
animal.snake
animal.type

Location

Generate location-related data:

location.buildingNumber
location.cardinalDirection
location.city
location.cityName
location.country
location.countryCode
location.county
location.direction
location.latitude
location.longitude
location.nearbyGPSCoordinate
location.ordinalDirection
location.secondaryAddress
location.state
location.stateAbbr
location.street
location.streetAddress
location.streetName
location.timeZone
location.zipCode
location.zipCodeByState

Phone Numbers

phone.imei
phone.number

E-commerce

Some realistic product names.

commerce.department
commerce.isbn
commerce.price
commerce.product
commerce.productAdjective
commerce.productDescription
commerce.productMaterial
commerce.productName

Company

company.name
company.catchPhrase
company.buzzPhrase
company.catchPhraseAdjective
company.catchPhraseDescriptor
company.catchPhraseNoun
company.buzzVerb
company.buzzNoun
company.buzzAdjective

Color

Generate color-related data:

color.cmyk
color.colorByCSSColorSpace
color.cssSupportedFunction
color.cssSupportedSpace
color.hsl
color.human
color.hwb
color.lab
color.lch
color.rgb
color.space

Finance

finance.accountNumber
finance.amount
finance.bic
finance.bitcoinAddress
finance.creditCardCVV
finance.creditCardIssuer
finance.creditCardNumber
finance.currency
finance.currencyCode
finance.currencyName
finance.currencySymbol
finance.ethereumAddress
finance.iban
finance.litecoinAddress
finance.mask
finance.pin
finance.routingNumber
finance.transactionDescription
finance.transactionType

Online Forum

hacker.abbreviation
hacker.adjective
hacker.noun
hacker.verb
hacker.ingverb
hacker.phrase

Images

Generates links to images for the following categories.

E.g. The {{faker 'image.urlLoremFlickr' 'animals'}} syntax will generate a link to http://placeimg.com/640/480/animals. The image.url syntax will generate a link to any random image.

image.avatar
image.avatarGitHub
image.avatarLegacy
image.dataUri
image.url
image.urlLoremFlickr
image.urlPicsumPhotos
image.urlPlaceholder

Internet

internet.color
internet.displayName
internet.domainName
internet.domainSuffix
internet.email
internet.emoji
internet.httpMethod
internet.httpStatusCode
internet.ip
internet.ipv4
internet.ipv6
internet.mac
internet.password
internet.port
internet.protocol
internet.url
internet.userAgent
internet.userName

Database

database.column
database.type
database.collation
database.engine

Git

git.branch
git.commitDate
git.commitEntry
git.commitMessage
git.commitSha
git.shortSha

Music

Generate music-related data:

music.genre
music.songName

System

system.commonFileExt
system.commonFileName
system.commonFileType
system.cron
system.directoryPath
system.fileExt
system.fileName
system.filePath
system.fileType
system.mimeType
system.networkInterface
system.semver

Science

Generate science-related data:

science.chemicalElement
science.unit

Vehicle

Generate vehicle-related data:

vehicle.bicycle
vehicle.color
vehicle.fuel
vehicle.manufacturer
vehicle.model
vehicle.type
vehicle.vehicle
vehicle.vin
vehicle.vrm

Troubleshooting

When there are syntax errors in defining templates, Beeceptor tries to recover safely and attempts to generate the mocked response. However, there can be unrecoverable errors.

1. If the faker syntax has any issue, you shall get Faker Attribute Error: Missing or wrong syntax in the response.
2. If there is an unrecoverable error, a response with 561 HTTP status code is returned. In such cases, you should review the template's syntax and correct it.