Package

chai

BDD/TDD assertion library for node.js and the browser. Test framework agnostic.

v6.2.2, 22 Dec 2025MITESM onlyTypes: NoneTesting

$ npm install chai

npm GitHub Homepage

Key numbers

As of 25 Sept 2026

Weekly downloads: 85.9m; +273% over 12 months
Gzip bundle size: -; No Bundlephobia data
Dependencies: 0; Direct, from package.json
Last release: 9 months ago; v6.2.2
GitHub stars: 8.3k; 725 forks
Open issues / PRs: 83 / 9
Contributors: 204
Commits, last 52 weeks: 121

Downloads

Last week 2026-09-15 to 2026-09-21

Weekly npm downloads, one point per week, weeks starting 23 Sept 2025 to 15 Sept 2026. The y axis starts at zero.

85,876,376 downloads last week, 410,936,404 in the last month. The 12-month change of +273% compares the average of the last 4 weeks with the first 4 weeks of the series.

Maintenance

Releases, last 12 months: 4104 in total
Latest version: 6.2.2, 22 Dec 20259 months ago
First published: 7 Dec 2011
Last push to GitHub: 23 Sept 20261 day before the snapshot
Repository archived: No
Open issues: 83
Open pull requests: 9
Commits, last 52 weeks: 121
Dependents on npm: 10,618

Major versions

v6 first release 6.0.0, 22 Aug 2025
v5 first release 5.0.0, 28 Dec 2023
v4 first release 4.0.0, 26 May 2017
v3 first release 3.0.0, 3 Jun 2015
v2 first release 2.0.0, 11 Feb 2015
v1 first release 1.0.0, 15 May 2012
v0 first release 0.0.1, 7 Dec 2011

Recent releases

Version	Published
6.2.2	22 Dec 2025
6.2.1	11 Nov 2025
6.2.0	27 Sept 2025
6.1.0	27 Sept 2025
5.3.3	22 Aug 2025
6.0.1	22 Aug 2025
6.0.0	22 Aug 2025
5.3.2	22 Aug 2025
5.3.1	18 Aug 2025
5.3.0	18 Aug 2025
5.2.2	18 Aug 2025
5.2.1	8 Jul 2025
5.2.0	14 Feb 2025
5.1.2	23 Oct 2024

Compatibility

Module format: ESM onlyFrom package.json type, main and exports fields
TypeScript types: None
Node.js engine range: >=18
Runtimes: -
Unpacked size (npm): 143 kB
Dependencies (0): None

Install

npm install chai

CDN

jsDelivr: 649.1k requests in 30 days

jsDelivrhttps://cdn.jsdelivr.net/npm/chai@6.2.2/
unpkghttps://unpkg.com/chai@6.2.2/
esm.shhttps://esm.sh/chai@6.2.2

Alternatives

Package	Weekly downloads	Gzip	Last release	Module	Comparison
mocha Classic, reliable, trusted test framework for Node.js and the browser	10.8m	-	7 days ago	ESM only	-
should test framework agnostic BDD-style assertions	3.4m	-	8 years ago	ESM + CommonJS	-
jasmine-core Simple JavaScript testing framework for browsers and node.js	5m	-	1 month ago	CommonJS	-
sinon JavaScript test spies, stubs and mocks.	8.3m	-	2 months ago	ESM + CommonJS	-

Sources: npm registry, npm downloads API, GitHub API, jsDelivr. Data fetched 25 Sept 2026.

Indexability: Indexed.