The configuration file 'appsettings.json' was not found and is not optional
In later .net core versions a *.csproj file is used instead of the project.json file.
You can modify the file to get the desired result by adding:
<ItemGroup> <Content Update="appsettings.json"> <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory> </Content> </ItemGroup>
In My case the file appsettings.json existed in project folder, but it was set to Do not copy, I changed the setting to Copy always (see images below). And it worked for me.
It will automatically added following XML to your project.csproj file:
<ItemGroup> <Content Update="appsettings.json"> <CopyToOutputDirectory>Always</CopyToOutputDirectory> </Content></ItemGroup>I have looked at other answer, project.json is dead as this answer says.
In your project.json
ensure you have inlcuded appsettings.json as a copyToOutput
"buildOptions": { "emitEntryPoint": true, "preserveCompilationContext": true, "copyToOutput": { "include": [ "appsettings.json" ] } },