Chance.js review

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

Chance.js is an open-source JavaScript library for generating pseudo-random values in automated tests and other development tasks. It suits developers who need synthetic data directly in browser code or Node.js applications, rather than teams looking for a hosted workspace. The documented generators cover strings, numbers, names, addresses, dates, GUIDs, web values, locations, and finance-related values. Its MIT License and free open-source model make it a practical fit for lightweight test-data generation within JavaScript projects.

The library’s strongest feature is control over repeatable output. Seeded generation can produce the same random sequence across runs, which is useful when test cases need consistent inputs. String generation supports configurable length, character pools, casing, and symbols. Date values can be returned as date objects or strings, while GUID generation supports selectable versions. Browser use is available through a script include, and Node.js projects can install and use it as a module. These options keep common synthetic-data tasks close to the application code.

Chance.js is more focused than a full test-data platform or a broader developer library. It does not provide a hosted interface, database connectors, or a relational dataset workflow, and its verified feature breadth does not include file-generation coverage. Choose it when JavaScript-native random values, repeatable sequences, and straightforward integration are the priority. Teams that need connected datasets, generated files, or broader workflow coverage should consider a tool designed around those requirements instead.

Chance.js pros and cons

• Where it wins
  • Seeded generation supports repeatable random sequences.
  • Configurable strings, addresses, dates, and GUIDs.
  • Runs in browsers and Node.js with MIT licensing.
• Where it doesn't
  • Developer library rather than a hosted test-data platform.
  • No relational dataset workflow or database connectors.
  • Narrower coverage than libraries with file-generation features.

Chance.js fact sheet, pricing and score →

Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.

Last updated 7 Oct 2026 · How we research and update