> Portal Navigation: > > - Append `.md` to any URL under `https://dev.wix.com/docs/` to get its markdown version. > - Pages are either content pages (article or reference text) or menu pages (a list of links to child pages). > - To get a menu page, truncate any URL to a parent path and append `.md` (e.g. `https://dev.wix.com/docs/sdk.md`, `https://dev.wix.com/docs/sdk/core-modules.md`). > - Top-level index of all portals: https://dev.wix.com/docs/llms.txt > - Full concatenated docs: https://dev.wix.com/docs/llms-full.txt ## Resource: About Packages ## Article: About Packages ## Article Link: https://dev.wix.com/docs/develop-websites/articles/coding-with-velo/packages/about-packages.md ## Article Content: # Velo: About Packages When writing code, you often need to build some complex feature or functionality. Sometimes you discover that someone else already wrote and implemented the functionality that you need. Instead of reinventing the wheel and writing the same code over again, you can find a pre-built package or app written by others and incorporate it into your own code. Using pre-built packages, also known as code libraries, is a great way to minimize your development time and the amount of code you need to write. There are 2 types of pre-built packages available to add to your Velo site: * [Velo Packages](https://dev.wix.com/docs/develop-websites/articles/coding-with-velo/packages/working-with-velo-packages.md) * [npm Packages](https://dev.wix.com/docs/develop-websites/articles/coding-with-velo/packages/about-npm-packages.md) You can add packages to your site in the Package Manager, which you can access from the **Packages & Apps** section of the Code sidebar (Wix Editor) or the Code sidebar (Wix Studio). To add a package, click **Install Velo Package** or **Install packages from npm**. Then select the package you want and click **Install**. For more information, see the articles for each package type. If there isn't already a package that meets your needs, you can also create your own [custom app](#custom-apps) to reuse code and other functionality across multiple sites. ### Velo Packages Built using the Velo APIs, Velo packages are created specifically for Wix websites and work seamlessly with Wix elements and apps. Unlike npm packages, Velo package use cases are very specific to your Wix site. A Velo package can include backend code files, public code files, and npm packages. A Velo package's functionality is available for use through its exported functions. An editable **config.json** file may also be included for defining specific settings for a package. You can import the functions and use them in your site code just like you import and use exported functions that you write in .js and .web.js files.
**Note** If a Velo package includes an npm package, you won't see the npm package in the npm section of the Code sidebar (Wix Editor) or Code sidebar (Wix Studio).
Velo packages built by Wix allow you to add popular complex functionality to your site without spending hours writing code. Choose the Velo package you want, and import it on each site where you want to add the specific functionality. You can view all the code used to implement a package. Each Velo package contains a detailed README file explaining the package's functionality and the steps required for implementation. Some package functions are internal and can't be used directly in your site. See the package's README for the list of exposed functions available for use. To help you understand how to use specific Velo packages on your site, we added some examples to the [Coding Examples page](https://dev.wix.com/docs/coding-examples.md) that integrate Velo packages. Look for the **Velo package** tag ![](https://d2x3xhvgiqkx42.cloudfront.net/12345678-1234-1234-1234-1234567890ab/b4ae9703-4364-4550-a797-1cc95ed8046e/2021/11/24/fcdc7965-604e-4777-b2e0-782fe556303e/4f1a6077-5246-4368-bb9a-223d042d533a.png)  in the example. To learn more, see [Working with Velo Packages](https://dev.wix.com/docs/develop-websites/articles/coding-with-velo/packages/working-with-velo-packages.md).   ### npm Packages npm is the most popular registry of pre-built packages. The packages are built and maintained by npm developers. Velo allows you to install public npm packages in your site directly from the npm registry. It is your responsibility to follow the npm package's developer guidelines to understand the package's functionality, in what situations it can be used, and in what situations it should not be used. Once installed, you can import the package and use it in your code. To learn more, see [Working with npm Packages](https://dev.wix.com/docs/develop-websites/articles/coding-with-velo/packages/about-npm-packages.md). ### Custom Apps You can build custom apps using [Wix Blocks](https://dev.wix.com/docs/build-apps/develop-your-app/frameworks/wix-blocks/about-wix-blocks.md) to share custom functionality across your sites. Once a custom app is installed on your site, the site can import custom app code, use the custom app's widgets, and the custom app's [dashboard extensions](https://dev.wix.com/docs/build-apps/develop-your-app/extensions/dashboard-extensions/about-dashboard-extensions.md) and [collections](https://dev.wix.com/docs/build-apps/develop-your-app/frameworks/wix-blocks/cms-collections-in-blocks/about-cms-collections-in-blocks.md) are automatically added to the site. Learn more about [custom apps](https://dev.wix.com/docs/develop-websites/articles/coding-with-velo/packages/about-custom-apps.md) and how to [install custom apps on a site](https://dev.wix.com/docs/build-apps/develop-your-app/frameworks/wix-blocks/deploy-and-manage-blocks-apps/install-a-blocks-app-on-a-site.md).