faker-js/faker

Faker is a JavaScript/TypeScript library that generates large amounts of fake but realistic-looking data for use in software testing and development. When building an app, developers often need placeholder data, fake names, addresses, email addresses, dates, credit card numbers, to fill out a database or test how a UI looks without using real personal information. Faker automates this. The library works both in the browser and in Node.js (the server-side JavaScript runtime). It is organized into modules by data type: "Person" generates names, genders, job titles, and bios; "Location" generates addresses, zip codes, states, and countries; "Date" generates past, present, or future timestamps; "Finance" generates account numbers, transactions, and crypto addresses; "Commerce" generates product names and prices; and more. There is also a "Hacker" category that produces nonsensical but realistic-sounding tech jargon. A notable feature is localization: the library supports over 70 locales, so you can generate data that looks like it comes from a specific country, German addresses, Japanese names, and so on. You can also set a numeric "seed" value to make the random output reproducible, meaning the same seed always produces the same sequence of fake data, which is useful for consistent test results. The library is installed via npm (npm install --save-dev @faker-js/faker) and is released under the MIT open-source license.