Chance.js

Open Source

Minimalist generator of random strings, numbers, and structured fake data for JavaScript testing.

Visit website GitHub

Pricing

Free / Open source

Type

Automation

Languages

JavaScript, TypeScript

// VERDICT

Reach for Chance.js when you want flexible random data generation in JS with control over the values. Skip it when you want the richest realistic-data library (Faker.js), deterministic fixtures, or another language.

Best for

A JavaScript random generator for test and dev data - producing random strings, numbers, names and structured values, with fine-grained control over the randomness.

Avoid when

You want the largest realistic-data catalogue (Faker.js), deterministic fixtures, or a non-JS stack.

CI/CD fit

Library in tests/seeders · seedable for reproducibility

Languages

JavaScript · TypeScript

Team fit

JS/TS teams · Random test-data generation · Property-style data

Setup

Easy

Maintenance

Low

Learning

Beginner

Licence

Free / Open source

// BEST FOR

Generating random strings, numbers, names and values
Fine-grained control over randomness
Seeding for reproducible randomness
Lightweight test-data generation
Filling forms/fixtures with varied data
Property-style data variation

// AVOID WHEN

You want the largest realistic-data catalogue (Faker.js)
Deterministic fixed fixtures are needed
Your stack isn't JS
Exact known values are required for assertions
Strict business-rule data is needed
Minimal dependencies are mandated

// QUICK START

npm install -D chance
// const chance = new Chance(123); chance.name(); chance.integer({min:1,max:100});

// ALTERNATIVES TO CONSIDER

Tool	Choose it when
Faker.js	You want the richer realistic-data catalogue.
DbUnit	You want fixed datasets for DB tests.
Testcontainers	You want real seeded dependencies for integration tests.