Blazor hosted on vercel aka zeit now.sh

solrevdev profile image John Smith Originally published at solrevdev.com on ・3 min read

So, I decided it was time to play with Blazor WebAssembly which is in preview for ASP.NET Core 3.1.

I decided I wanted to publish the sample on Zeit’s now.sh platform which has now been rebranded Vercel

If you want to follow along this was my starting point

I use Visual Studio Code and for IDE support with vscode you will want to follow the instructions on this page

Firstly make sure you have .NET Core 3.1 SDK installed.

Optionally install the Blazor WebAssembly preview template by running the following command:

dotnet new -i Microsoft.AspNetCore.Components.WebAssembly.Templates::3.2.0-rc1.20223.4

Make any changes to the template that you like then when you are ready to publish enter the following command

dotnet publish -c Release

This will build and publish the assets you can deploy to the folder:


Make sure you have the now.sh command line tool installed.

npm i -g vercel
now login

Navigate to this folder and run the now command line tool for deploying.

cd bin/Release/netstandard2.1/publish/wwwroot
now --prod

Now you have deployed you app to vercel/now.sh.

This is my deployment https://blazor.now.sh/

You may notice that if you navigate to a page like https://blazor.now.sh/counter then hit F5 to reload you get a 404 not found error.

To fix this we need to create a configuration file to tell vercel to redirect 404’s to index.html.

Create a file in your project named vercel.json that will match the publish path


Use the following vercel.json configuration to tell the now.sh platform to redirect 404’s to the index.html page and let Blazor handle the routing

    "version": 2,
    "routes": [{"handle": "filesystem"}, {"src": "/.*", "dest": "/index.html"}]

Next we need to tell .NET Core to publish that file so open your .csproj file and add the following

    <None Include="publish/wwwroot/vercel.json" CopyToPublishDirectory="PreserveNewest" />

Finally you can create a deploy.sh file that can publish and deploy all in one command.

#!/usr/bin/env bash

dotnet publish -c Release
now --prod bin/Release/netstandard2.1/publish/wwwroot/

To run this make sure it has the correct permissions

chmod +x deploy.sh

And with that I can deploy Blazor WebAssembly to vercel’s now.sh platform at https://blazor.now.sh/

The code is now up on GitHub at https://github.com/solrevdev/blazor-on-vercel

Next up I am thinking of deploying a Web API backend for it to talk to.

Maybe a docker based deployment over at fly.io?

Success 🎉

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John Smith


full-time carer formally head of infrastructure and operations, senior full-stack #dotnetcore #aspnetcore #vuejs developer and software engineer.


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