Umbraco is primarily written in C#, stores data in a
relational database (commonly
Microsoft SQL Server) and runs on Microsoft Kestrel server which can run on Windows or Linux. Umbraco's
front-end is built upon Microsoft's
.NET, using
ASP.NET Core. Umbraco uses standard ASP.NET features such as ASP.NET "master pages" to facilitate the creation of reusable page layouts, and supports both
Razor and
XSLT. XSLT has been used for
scripting, and in the past there was much debate as to which yielded better performance, since
XML has been used for database storage and for the cache file (umbraco.config) Beginning with Umbraco 9, the platform underwent a major architectural transformation by migrating to
.NET 5 and
ASP.NET Core, a shift that enabled better performance, cross-platform capabilities, and improved scalability. This marked a move away from legacy
.NET Framework dependencies and brought Umbraco in line with Microsoft's modern development ecosystem. Since then, Umbraco has adopted Microsoft's Long-Term Support (LTS) release cadence, regularly updating its core to align with new .NET versions
Database tier In 2008, a
data abstraction layer for Umbraco was built, making it possible to support databases other than SQL Server. In version 4.0 of Umbraco, support for
MySQL, SQL Server and
VistaDB come as standard. With Umbraco 4.6, released in 2010, VistaDB support was removed, and replaced with support for SQL Server Express and SQL Server Compact Edition, due to licensing issues with VistaDB's parent company. As of Umbraco 6, support for MySQL has waned, as the development team has spent more time supporting Microsoft's SQL Server products. MySQL 5.6.5 or newer is required to support Umbraco 6.1 or newer. Umbraco 7 featured a completely revamped back-end administration UI, with the use of
AngularJS for a
single-page application experience. It has also been announced that they will implement Angular 2.0. Beginning with Umbraco 9, the platform's migration to .NET 5 and ASP.NET Core enabled broader cross-platform database compatibility. This included support for
SQLite, which is now commonly used in development and test environments. While Microsoft SQL Server remains the preferred option for production deployments, Umbraco's adoption of the modern .NET ecosystem has made it more flexible in supporting alternative data storage options in self-hosted scenarios.
Deployment The standard release of Umbraco is typically deployed on IIS in an environment which supports Full Trust. While a Full Trust environment is mandatory to install and operate the standard release, the codebase has been branched and modified to produce a version of the framework and backend UI which supports Medium Trust. Research has also been undertaken on running an Umbraco website on
Mono on Linux. Umbraco can be deployed on a single physical server running the database and web tier, and this deployment model can be appropriate for small low-cost sites. Umbraco sites which serve content under higher load can also be deployed on a
load balanced cluster. Load balanced Umbraco installations can use software or hardware load balancers, and load balanced network files can be shared using a
SAN,
NAS or a
cluster file system or using a file replication service between nodes in the cluster.
Releases Version 4.1 Beta II was released on 16 February 2010 which refactors a number of key components of the framework, published in January 2012. Problems (performance and code complexity) inherent in the architecture of the new Version 5 data access layer led to Version 5 being dropped in June 2012 despite having been released on a commercial license, and development efforts refocused on integrating selected Version 5
front end enhancements into Version 4. Version 6 was released on 31 January 2013, and was focused on additional support for MVC 4 and a new streamlined API. Version 7 was released on 21 November 2013. It is updated concurrently with version 6, but provides a redesign of the back-office user interface. Umbraco 8 was released on 26 February 2019. Umbraco 9 was released on 28 September 2021. This marks the first version fully on .NET 5 and ASP.NET Core. Umbraco 10 was released on 16 June 2022. This release brought Umbraco to .NET 6 and ASP.NET Core 6 and SQLite support. Umbraco 11 was released on 1 December 2022. This release brought Umbraco to .NET 7 and ASP.NET Core 7 and a new Block Grid Editor. Umbraco 12 was released on 29 June 2023. This release brought a headless API called the Content Delivery API, and support for Entity Framework Core. Umbraco 13 was released on 14 December 2023. This release brought Umbraco to .NET 8 and C# 12. Umbraco 14 was released on 30 May 2024. This release brought a new backoffice built in TypeScript and Lit, and removed the existing deprecated AngularJS version Umbraco 15 was released on 14 November 2024. This release brought Umbraco to .NET 9 and introduced Microsoft HybridCache and Tiptap RTE. Umbraco 16 was released on 12 June 2025. This version introduced Tiptap as the default rich text editor (RTE), replacing the previous editor. Tiptap was first made available in Umbraco 15. Other updates in version 16 included improvements to the back-office user interface and new options for locking, moving, and hiding properties. == Community ==