Azure DevOps (Server) had Mermaid support for a long time. Unfortunately that support was limited to the Wiki functionality.
This means that if you had markdown files somewhere else in your repo; for example as part of your readme.md file or an architecture decision record(ADR), any mermaid diagram inside these files was not rendered.
Some extensions exists in the Visual Studio marketplace that tried to solve this, but when using these extensions I noticed that none of these extensions were bug free and all had limitations or caused problems with other features inside Azure DevOps.
With the December 2025 release of Azure DevOps, you no longer need a 3th party solution as this feature is finally available.
Create a mermaid diagram in any .md file:
And the preview tab will now nicely render your diagram:
Nice!
More information
Markdown Syntax for Files, Widgets, Wikis - Azure DevOps | Microsoft Learn
Azure DevOps Server Release Notes - Azure DevOps Server & TFS | Microsoft Learn

