Azure Functions SendGrid bindings

This article explains how to send email by using SendGrid bindings in Azure Functions. Azure Functions supports an output binding for SendGrid.

This is reference information for Azure Functions developers. If you're new to Azure Functions, start with the following resources:

Install extension

The extension NuGet package you install depends on the C# mode you're using in your function app:

Functions execute in the same process as the Functions host. To learn more, see Develop C# class library functions using Azure Functions.

The functionality of the extension varies depending on the extension version:

Add the extension to your project by installing the NuGet package, version 3.x.

Install bundle

Starting with Functions version 2.x, the HTTP extension is part of an extension bundle, which is specified in your host.json project file. To learn more, see extension bundle.

This version of the extension should already be available to your function app with extension bundle, version 2.x.

Example

A C# function can be created using one of the following C# modes:

  • In-process class library: compiled C# function that runs in the same process as the Functions runtime.
  • Isolated process class library: compiled C# function that runs in a process isolated from the runtime. Isolated process is required to support C# functions running on .NET 5.0.
  • C# script: used primarily when creating C# functions in the Azure portal.

The following examples shows a C# function that uses a Service Bus queue trigger and a SendGrid output binding.

The following example is a synchronous execution:

using SendGrid.Helpers.Mail;
using System.Text.Json;

...

[FunctionName("SendEmail")]
public static void Run(
    [ServiceBusTrigger("myqueue", Connection = "ServiceBusConnection")] Message email,
    [SendGrid(ApiKey = "CustomSendGridKeyAppSettingName")] out SendGridMessage message)
{
    var emailObject = JsonSerializer.Deserialize<OutgoingEmail>(Encoding.UTF8.GetString(email.Body));

    message = new SendGridMessage();
    message.AddTo(emailObject.To);
    message.AddContent("text/html", emailObject.Body);
    message.SetFrom(new EmailAddress(emailObject.From));
    message.SetSubject(emailObject.Subject);
}

public class OutgoingEmail
{
    public string To { get; set; }
    public string From { get; set; }
    public string Subject { get; set; }
    public string Body { get; set; }
}

This example shows asynchronous execution:

using SendGrid.Helpers.Mail;
using System.Text.Json;

...

[FunctionName("SendEmail")]
public static async Task Run(
 [ServiceBusTrigger("myqueue", Connection = "ServiceBusConnection")] Message email,
 [SendGrid(ApiKey = "CustomSendGridKeyAppSettingName")] IAsyncCollector<SendGridMessage> messageCollector)
{
    var emailObject = JsonSerializer.Deserialize<OutgoingEmail>(Encoding.UTF8.GetString(email.Body));

    var message = new SendGridMessage();
    message.AddTo(emailObject.To);
    message.AddContent("text/html", emailObject.Body);
    message.SetFrom(new EmailAddress(emailObject.From));
    message.SetSubject(emailObject.Subject);

    await messageCollector.AddAsync(message);
}

public class OutgoingEmail
{
    public string To { get; set; }
    public string From { get; set; }
    public string Subject { get; set; }
    public string Body { get; set; }
}

You can omit setting the attribute's ApiKey property if you have your API key in an app setting named "AzureWebJobsSendGridApiKey".

The following example shows a SendGrid output binding in a function.json file and a JavaScript function that uses the binding.

Here's the binding data in the function.json file:

{
    "bindings": [
        {
            "name": "$return",
            "type": "sendGrid",
            "direction": "out",
            "apiKey" : "MySendGridKey",
            "to": "{ToEmail}",
            "from": "{FromEmail}",
            "subject": "SendGrid output bindings"
        }
    ]
}

The configuration section explains these properties.

Here's the JavaScript code:

module.exports = function (context, input) {
    var message = {
        "personalizations": [ { "to": [ { "email": "sample@sample.com" } ] } ],
        from: { email: "sender@contoso.com" },
        subject: "Azure news",
        content: [{
            type: 'text/plain',
            value: input
        }]
    };

    return message;
};

Complete PowerShell examples aren't currently available for SendGrid bindings.

The following example shows an HTTP-triggered function that sends an email using the SendGrid binding. You can provide default values in the binding configuration. For instance, the from email address is configured in function.json.

{
  "scriptFile": "__init__.py",
  "bindings": [
    {
      "type": "httpTrigger",
      "authLevel": "function",
      "direction": "in",
      "name": "req",
      "methods": ["get", "post"]
    },
    {
      "type": "http",
      "direction": "out",
      "name": "$return"
    },
    {
      "type": "sendGrid",
      "name": "sendGridMessage",
      "direction": "out",
      "apiKey": "SendGrid_API_Key",
      "from": "sender@contoso.com"
    }
  ]
}

The following function shows how you can provide custom values for optional properties.

import logging
import json
import azure.functions as func

def main(req: func.HttpRequest, sendGridMessage: func.Out[str]) -> func.HttpResponse:

    value = "Sent from Azure Functions"

    message = {
        "personalizations": [ {
          "to": [{
            "email": "user@contoso.com"
            }]}],
        "subject": "Azure Functions email with SendGrid",
        "content": [{
            "type": "text/plain",
            "value": value }]}

    sendGridMessage.set(json.dumps(message))

    return func.HttpResponse(f"Sent")

The following example uses the @SendGridOutput annotation from the Java functions runtime library to send an email using the SendGrid output binding.

package com.function;

import java.util.*;
import com.microsoft.azure.functions.annotation.*;
import com.microsoft.azure.functions.*;

public class HttpTriggerSendGrid {

    @FunctionName("HttpTriggerSendGrid")
    public HttpResponseMessage run(

        @HttpTrigger(
            name = "req",
            methods = { HttpMethod.GET, HttpMethod.POST },
            authLevel = AuthorizationLevel.FUNCTION)
                HttpRequestMessage<Optional<String>> request,

        @SendGridOutput(
            name = "message",
            dataType = "String",
            apiKey = "SendGrid_API_Key",
            to = "user@contoso.com",
            from = "sender@contoso.com",
            subject = "Azure Functions email with SendGrid",
            text = "Sent from Azure Functions")
                OutputBinding<String> message,

        final ExecutionContext context) {

        final String toAddress = "user@contoso.com";
        final String value = "Sent from Azure Functions";

        StringBuilder builder = new StringBuilder()
            .append("{")
            .append("\"personalizations\": [{ \"to\": [{ \"email\": \"%s\"}]}],")
            .append("\"content\": [{\"type\": \"text/plain\", \"value\": \"%s\"}]")
            .append("}");

        final String body = String.format(builder.toString(), toAddress, value);

        message.setValue(body);

        return request.createResponseBuilder(HttpStatus.OK).body("Sent").build();
    }
}

Attributes

Both in-process and isolated process C# libraries use attributes to define the output binding. C# script instead uses a function.json configuration file.

In in-process function apps, use the SendGridAttribute, which supports the following parameters.

Attribute/annotation property Description
ApiKey The name of an app setting that contains your API key. If not set, the default app setting name is AzureWebJobsSendGridApiKey.
To (Optional) The recipient's email address.
From (Optional) The sender's email address.
Subject (Optional) The subject of the email.
Text (Optional) The email content.

Annotations

The SendGridOutput annotation allows you to declaratively configure the SendGrid binding by providing the following configuration values.

Configuration

The following table lists the binding configuration properties available in the function.json file and the SendGrid attribute/annotation.

function.json property Description
type Must be set to sendGrid.
direction Must be set to out.
name The variable name used in function code for the request or request body. This value is $return when there is only one return value.
apiKey The name of an app setting that contains your API key. If not set, the default app setting name is AzureWebJobsSendGridApiKey.
to (Optional) The recipient's email address.
from (Optional) The sender's email address.
subject (Optional) The subject of the email.
text (Optional) The email content.

Optional properties may have default values defined in the binding and either added or overridden programmatically.

When you're developing locally, add your application settings in the local.settings.json file in the Values collection.

host.json settings

This section describes the configuration settings available for this binding in versions 2.x and higher. Settings in the host.json file apply to all functions in a function app instance. The example host.json file below contains only the version 2.x+ settings for this binding. For more information about function app configuration settings in versions 2.x and later versions, see host.json reference for Azure Functions.

Note

For a reference of host.json in Functions 1.x, see host.json reference for Azure Functions 1.x.

{
    "version": "2.0",
    "extensions": {
        "sendGrid": {
            "from": "Azure Functions <samples@functions.com>"
        }
    }
}
Property Default Description
from n/a The sender's email address across all functions.

Next steps