# Extending Umbraco

- [Overview](/umbraco-cms/extending/build-on-umbraco-functionality.md): Learn more about how to extend and build in the features and functionalities with the Umbraco CMS.
- [Health Check](/umbraco-cms/extending/health-check.md): Health Checks are used to determine the state of your Umbraco project. Learn more about each of them in this section.
- [Health Check Guides](/umbraco-cms/extending/health-check/guides.md)
- [Click-Jacking Protection](/umbraco-cms/extending/health-check/guides/clickjackingprotection.md): Learn how to protect your Umbraco site from clickjacking attacks using X-Frame-Options and security headers.
- [Content Content Security Policy (CSP)](/umbraco-cms/extending/health-check/guides/contentsecuritypolicy.md): Implement a Content Security Policy (CSP) to protect your Umbraco site from XSS and data injection.
- [Content/MIME Sniffing Protection](/umbraco-cms/extending/health-check/guides/contentsniffingprotection.md): Protect your Umbraco site from MIME sniffing vulnerabilities using security headers like X-Content-Type-Options.
- [Cross-site scripting Protection (X-XSS-Protection header)](/umbraco-cms/extending/health-check/guides/crosssitescriptingprotection.md)
- [Debug Compilation Mode](/umbraco-cms/extending/health-check/guides/debugcompilationmode.md): Disable debug compilation mode in Umbraco to boost performance by updating JSON configuration.
- [Excessive Headers](/umbraco-cms/extending/health-check/guides/excessiveheaders.md)
- [Fixed Application Url](/umbraco-cms/extending/health-check/guides/fixedapplicationurl.md)
- [Folder & File Permissions](/umbraco-cms/extending/health-check/guides/folderandfilepermissions.md)
- [HTTPS Configuration](/umbraco-cms/extending/health-check/guides/httpsconfiguration.md)
- [Notification Email Settings](/umbraco-cms/extending/health-check/guides/notificationemail.md)
- [SMTP](/umbraco-cms/extending/health-check/guides/smtp.md)
- [Strict-Transport-Security Header](/umbraco-cms/extending/health-check/guides/stricttransportsecurityheader.md): Learn about the health checks that check for cookie hijacking and protocol downgrade attacks protection.
- [Language Files & Localization](/umbraco-cms/extending/language-files.md): This article overviews how an Umbraco CMS website uses and manages localization with language files.
- [.NET Localization](/umbraco-cms/extending/language-files/net-localization.md): NET Umbraco Core Localization files.
- [Backoffice Search](/umbraco-cms/extending/backoffice-search.md): A guide to customization of Backoffice Search
- [Creating a Custom Database Table](/umbraco-cms/extending/database.md): A guide to creating a custom Database table in Umbraco
- [Creating a Custom Seed Key Provider](/umbraco-cms/extending/creating-custom-seed-key-provider.md): A guide to creating a custom seed key provider for Umbraco
- [Embedded Media Providers](/umbraco-cms/extending/embedded-media-providers.md): A guide to creating a custom embed providers in Umbraco
- [Custom File Systems (IFileSystem)](/umbraco-cms/extending/filesystemproviders.md): A guide to creating custom file systems in Umbraco
- [Using Azure Blob Storage for Media and ImageSharp Cache](/umbraco-cms/extending/filesystemproviders/azure-blob-storage.md): Setup your site to use Azure Blob storage for media and ImageSharp cache
- [Configuring Azure Key Vault](/umbraco-cms/extending/key-vault.md): A guide for configuring Azure Key Vault
- [Server Events From SignalR](/umbraco-cms/extending/server-events.md): Describes server events emitted via a SignalR hub and available for consumption in the backoffice
- [Flag Providers](/umbraco-cms/extending/flag-providers.md): Describes how to use provide flags in management API responses for use in presenting additional details to consumers.
- [Packages](/umbraco-cms/extending/packages.md): A package extends the functionality of Umbraco to provide additional functionality to editors, developers, site visitors, and all other types of users of Umbraco.
- [Creating a Package](/umbraco-cms/extending/packages/creating-a-package.md): Tutorial to create a package in Umbraco
- [Language file for packages](/umbraco-cms/extending/packages/language-files-for-packages.md): Information on how to use language files to make your Umbraco package UI support multiple languages
- [Listing a Package on the Umbraco Marketplace](/umbraco-cms/extending/packages/listing-on-marketplace.md): Information on how to list your package on the Umbraco Marketplace.
- [Good practice and defaults](/umbraco-cms/extending/packages/good-practice-and-defaults.md): Information on good practices and common defaults for Umbraco package development.
- [Packages on Umbraco Cloud](/umbraco-cms/extending/packages/packages-on-umbraco-cloud.md): Things to consider for package development and usage in Umbraco Cloud
- [Installing and Uninstalling Packages](/umbraco-cms/extending/packages/installing-and-uninstalling-packages.md): The process of installing and, in turn, uninstalling packages in your Umbraco CMS website.
- [Maintaining packages](/umbraco-cms/extending/packages/maintaining-packages.md): Once you've created and published your package, here is what's involved in it's ongoing maintenance
- [Create accessible Umbraco packages](/umbraco-cms/extending/packages/accessibility.md)
- [Example Package Repository](/umbraco-cms/extending/packages/example-package-repository.md): Suggestions for organizing an Umbraco package source code repository.
- [Single Block Migration](/umbraco-cms/extending/single-block-migration.md)