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Email with Attachments (Java)

Use the ACS Email SDK when you need to send receipts, reports, or screenshots.

Attachment limits

ACS email supports up to 10 attachments per message and 10 MB per attachment.

This recipe walks these steps in order:

flowchart TD
    START["Email with Attachments (Java)"]
    N1["Setup"]
    N2["Build the message"]
    N3["Multiple attachment types"]
    N4["Practical notes"]
    START --> N1
    N1 --> N2
    N2 --> N3
    N3 --> N4

Setup

Create an EmailClient from the connection string stored in Key Vault or App Configuration.

Item Value
SDK com.azure:azure-communication-email
Auth Connection string
Attachment data BinaryData from file bytes

Build the message

Create an EmailMessage, then add EmailAttachment instances for each file.

import com.azure.communication.email.EmailClient;
import com.azure.communication.email.EmailClientBuilder;
import com.azure.communication.email.models.EmailAttachment;
import com.azure.communication.email.models.EmailMessage;
import com.azure.communication.email.models.EmailRecipients;
import com.azure.communication.email.models.EmailAddress;
import com.azure.communication.email.models.EmailContent;
import com.azure.core.util.BinaryData;

import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Base64;

public class EmailWithAttachmentsExample {
    public static void main(String[] args) throws Exception {
        String connectionString = System.getenv("ACS_EMAIL_CONNECTION_STRING");
        String sender = "DoNotReply@contoso.com";
        String recipient = "user@contoso.com";

        EmailClient client = new EmailClientBuilder()
            .connectionString(connectionString)
            .buildClient();

        byte[] invoiceBytes = Files.readAllBytes(Path.of("invoice.pdf"));
        byte[] logoBytes = Files.readAllBytes(Path.of("logo.png"));

        // Base64 is useful when you need to inspect or forward the payload yourself.
        String invoiceBase64 = Base64.getEncoder().encodeToString(invoiceBytes);
        System.out.println("Invoice bytes (base64 preview): " + invoiceBase64.substring(0, 24) + "...");

        EmailAttachment invoice = new EmailAttachment(
            "invoice.pdf",
            "application/pdf",
            BinaryData.fromBytes(invoiceBytes));

        EmailAttachment logo = new EmailAttachment(
            "logo.png",
            "image/png",
            BinaryData.fromBytes(logoBytes));

        EmailAttachment csv = new EmailAttachment(
            "summary.csv",
            "text/csv",
            BinaryData.fromBytes(Files.readAllBytes(Path.of("summary.csv"))));

        EmailMessage message = new EmailMessage()
            .setSenderAddress(sender)
            .setRecipients(new EmailRecipients().setTo(List.of(new EmailAddress(recipient))))
            .setContent(new EmailContent()
                .setSubject("Monthly package")
                .setPlainText("Attached are the invoice, logo, and summary.")
                .setHtml("<p>Attached are the invoice, logo, and summary.</p>"));

        message.getAttachments().add(invoice);
        message.getAttachments().add(logo);
        message.getAttachments().add(csv);

        client.send(message);
        System.out.println("Message queued.");
    }
}

Multiple attachment types

  • application/pdf for invoices and statements
  • image/png or image/jpeg for screenshots
  • text/csv for exports and reports
  • application/zip for bundles

Practical notes

Keep attachments small

Large files slow down delivery and increase the chance of transient failures. Prefer links for oversized artifacts.

If you need to attach generated content, write it to disk or bytes first, then wrap it with BinaryData.fromBytes(...).

See Also

Sources

  • https://learn.microsoft.com/en-us/azure/communication-services/quickstarts/email/send-email-advanced/send-email-with-attachments
  • https://learn.microsoft.com/en-us/azure/communication-services/concepts/email/email-attachment