# knockout

> Knockout makes it easier to create rich, responsive UIs with JavaScript

Latest version **3.5.3** (published 2026-03-25) · MIT license · 0 weekly downloads

## Install

```sh
npm install knockout
pnpm add knockout
yarn add knockout
bun add knockout
```

## Health

**Score 60/100 (C)** — status: active.

Positive: has types; no vulnerabilities; high quality score; popular repo.

Warnings: low downloads; no esm support.

## Facts

| | |
|---|---|
| Version | 3.5.3 |
| Published | 2026-03-25 |
| First published | 2012-05-09 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | bundled |
| Module format | CommonJS |
| Dependencies | 0 |
| Unpacked size | 425.6 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 10557 |
| Author | The Knockout.js team |
| Maintainers | mbest, stevesanderson |

## Links

- npm: https://www.npmjs.com/package/knockout
- Repository: https://github.com/knockout/knockout
- Homepage: http://knockoutjs.com/
- Issues: https://github.com/knockout/knockout/issues
- npm.io page: https://npm.io/package/knockout

## Recent versions

- 3.5.3 (latest) — 2026-03-25
- 3.5.0-rc2 (rc) — 2018-09-08
- 3.5.0-beta (beta) — 2018-01-12
- 3.5.2 — 2026-03-09
- 3.5.1 — 2019-11-05
- 3.5.0 — 2019-02-21
- 3.5.0-rc — 2018-04-26
- 3.4.2 — 2017-03-06
- 3.4.1 — 2016-11-08
- 3.4.0 — 2015-11-17
- 3.3.0 — 2015-02-18
- 3.2.0 — 2014-08-17
- 3.1.0 — 2014-03-07
- 2.3.0-pre — 2014-03-07
- 2.3.0-rc — 2014-03-07
- … 5 more at https://npm.io/package/knockout/versions

## README

# Knockout

**Knockout** is a JavaScript [MVVM](https://en.wikipedia.org/wiki/Model_View_ViewModel) (a modern variant of MVC) library that makes it easier to create rich, desktop-like user interfaces with JavaScript and HTML. It uses *observers* to make your UI automatically stay in sync with an underlying data model, along with a powerful and extensible set of *declarative bindings* to enable productive development.

## Getting started

[![Join the chat at https://gitter.im/knockout/knockout](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/knockout/knockout?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)

**Totally new to Knockout?** The most fun place to start is the [online interactive tutorials](https://learn.knockoutjs.com/).

For more details, see

* Documentation on [the project's website](https://knockoutjs.com/documentation/introduction.html)
* Online examples at [http://knockoutjs.com/examples/](https://knockoutjs.com/examples/)

## Downloading Knockout

You can [download released versions of Knockout](https://knockoutjs.com/downloads/) from the project's website.

For Node.js developers, Knockout is also available from [npm](https://npmjs.org/) - just run `npm install knockout`.

## Building Knockout from sources

If you prefer to build the library yourself:

1. **Clone the repo from GitHub**

   ```sh
   git clone https://github.com/knockout/knockout.git
   cd knockout
   ```

2. **Acquire build dependencies.**

   Make sure you have [Node.js](https://nodejs.org/) and [Java](https://www.java.com/en/) installed on your workstation. These are only needed to _build_ Knockout from sources. Knockout itself has no dependency on Node.js or Java once it is built (it works with any server technology or none). Now run:

   ```sh
   npm install
   ```

3. **Run the build tool**

   ```sh
   npm run grunt
   ```

   Now you'll find the built files in `build/output/`.

   To run a single task, use `--`

   ```sh
   npm run grunt -- build:debug
   ```

## Running the tests

```sh
npm test              # All tests (Node.js + headless Chrome)
npm run test:node     # Node.js non-DOM specs only
npm run test:browser  # Headless Chrome specs only
npm run grunt         # Build and test against production output
```

For interactive debugging, open `spec/runner.html` in your browser.

## License

MIT license - [https://www.opensource.org/licenses/mit-license.php](https://www.opensource.org/licenses/mit-license.php)

---
_Source: https://npm.io/package/knockout · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._