A published Blazor WebAssembly instance is just a collection of files that can be loaded into a browser. If these files are hosted on the API, running the API means the UI is running as well, probably from the same address. In this case it’s a little different to debug compared to launching it standalone, but not any more complicated.
You will need the following:
In our case, the API runs on a URL like https://localhost:2200/api
and the Blazor WASM UI can be accessed from https://localhost:2200
. To debug the UI, another debug session can be spun up in VS Code. To add a new launch profile, press Ctrl+Shift+P
and select Debug: Add Configuration...
or edit launch.json
directly. Add the following configuration:
{
"name": "Attach to Hosted UI",
"type": "blazorwasm",
"request": "attach",
"url": "https://localhost:2200"
}
To launch and debug both the API and the UI at the same time, add the following (where Debug API
is the name of the API launch task) as a Compound Configuration:
{
"name": "Debug Full-Stack",
"configurations": [
"Debug API",
"Attach to Hosted UI"
],
"stopAll": true
}
It’s worth noting that Microsoft’s Blazor Debugging Documentation suggests the need to add special tags to the .csproj
file. This isn’t necessary for local debugging at least, but may help if you need to debug a published app.
© Copyright 2025
Phil Watson
Last updated
Thursday, 29/May/2025 09:38 +1000