Azure Function App Deployment Fails with “Invalid Binding Configuration” Error

Question

I’m encountering an issue deploying an HTTP-triggered Azure Function (v4, .NET 8) to Azure App Service from Visual Studio 2022 (17.9.6). The deployment fails with the error: “Invalid binding configuration: The binding type(s) 'httpTrigger' are not registered.” My function runs fine locally in Azure Functions Core Tools (v4.0.5455). Setup: Windows 11, Azure SDK 2.37.0, Function App on Consumption plan (West US).

Code Snippet (Function1.cs):

using Microsoft.Azure.Functions.Worker;

using Microsoft.Extensions.Logging;

namespace MyFunctionApp

{

public class Function1

{

    private readonly ILogger _logger;

    public Function1(ILoggerFactory loggerFactory)

    {

        _logger = loggerFactory.CreateLogger<Function1>();

    }

    [Function("Function1")]

    public async Task<HttpResponseData> Run(

        [HttpTrigger(AuthorizationLevel.Function, "get", "post")] HttpRequestData req)

    {

        _logger.LogInformation("C# HTTP trigger function processed a request.");

        var response = req.CreateResponse(HttpStatusCode.OK);

        await response.WriteStringAsync("Hello, Azure!");

        return response;

    }

}

}

host.json:

{

"version": "2.0",

"logging": {

"applicationInsights": {

  "samplingSettings": {

    "isEnabled": true

  }

}

}

}

Steps Tried:

• Verified Microsoft.Azure.Functions.Worker and Microsoft.Azure.Functions.Worker.Sdk NuGet packages (v1.16.0).
• Updated Azure Functions Core Tools to latest version.
• Recreated Function App in Azure Portal; same error.
• Checked Application Settings: FUNCTIONS_WORKER_RUNTIME set to dotnet-isolated.
• Ran func azure functionapp publish from CLI; same binding error in logs.
• Reviewed Azure Portal logs: “Host initialization failed: Invalid binding configuration.”

Error Log (Azure Portal):

2025-05-30T08:15:22Z [Error] Host initialization failed: Invalid binding configuration: The binding type(s) 'httpTrigger' are not registered. Please ensure the binding type is correctly configured in your function.json or function code.

Could this be a misconfiguration in host.json or a compatibility issue with .NET 8 isolated mode? Any suggestions for debugging or fixing the binding registration? Thanks for your expertise! 😊

Answer 1

Is the correct bindings information present in the functions.metadata file, when you build the project, it should be located in the bin\Debug\net8.0 or bin\Release\net8.0 directory within your project directory. In dotnet projects this file is generated when you build the project and serves to provide the same information as the function.json file does. The contents of the file from a sample project are as follows:

[
  {
    "name": "Function1",
    "scriptFile": "FunctionApp.dll",
    "entryPoint": "FunctionApp.Function1.Run",
    "language": "dotnet-isolated",
    "properties": {
      "IsCodeless": false
    },
    "bindings": [
      {
        "name": "req",
        "direction": "In",
        "type": "httpTrigger",
        "authLevel": "Function",
        "methods": [
          "get",
          "post"
        ],
        "properties": {}
      },
      {
        "name": "$return",
        "type": "http",
        "direction": "Out"
      }
    ]
  }
]

I would also ensure that the Microsoft.Azure.Functions.Worker.Extensions.Http.dll assembly file is present alongside the functions.metadata file, as that is the assembly file that contains the HttpTrigger attribute class and the associated trigger implementation.

If the information in functions.metadata file is correct, ensure that the correct framework and extension packages are referenced in the projects .csproj file. The packages present in the sample project are as follows:

<FrameworkReference Include="Microsoft.AspNetCore.App" />
<PackageReference Include="Microsoft.Azure.Functions.Worker" Version="2.0.0" />
<PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http" Version="3.3.0" />
<PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore" Version="2.0.2" />
<PackageReference Include="Microsoft.Azure.Functions.Worker.Sdk" Version="2.0.4" />

If the above is correct, I would check the configuration of the service in Azure Portal. I've has a couple of issues in the past where the function app had incorrect configuration with some values relevant for the in-process and some for the isolated model. I would read through the migration guide and compare the configuration to your function app configuration.

Answer 2

Based on the additional information it seems like a dependency version issue. I've seen this a couple of times before, where some of the packages require different versions of the same dependency assembly and it causes a conflict. Try replacing the packages in your project file with the referenced versions below, from the Visual Studio Build menu run the Clean Solution task, then build the project and try deploying again.

You mentioned you are using Application Insights, so the full list of packages referenced with versions in my sample project are as follows:

<PackageReference Include="Microsoft.ApplicationInsights.WorkerService" Version="2.23.0" />
<PackageReference Include="Microsoft.Azure.Functions.Worker.ApplicationInsights" Version="2.0.0" />
<PackageReference Include="Microsoft.Azure.Functions.Worker" Version="2.0.0" />
<PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http" Version="3.3.0" />
<PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore" Version="2.0.2" />
<PackageReference Include="Microsoft.Azure.Functions.Worker.Sdk" Version="2.0.4" />

The sample project deploys fine to Azure in the North Europe region when I tried.