diff --git a/app/src/main/java/com/sun/mail/smtp/SMTPTransport.java b/app/src/main/java/com/sun/mail/smtp/SMTPTransport.java
index 2587cb652c..74e6555c62 100644
--- a/app/src/main/java/com/sun/mail/smtp/SMTPTransport.java
+++ b/app/src/main/java/com/sun/mail/smtp/SMTPTransport.java
@@ -1300,6 +1300,16 @@ public class SMTPTransport extends Transport {
 	try {
 	    mailFrom();
 	    rcptTo();
+	    eu.faircode.email.ObjectHolder<Integer> total = new eu.faircode.email.ObjectHolder<>();
+	    total.value = 0;
+	    this.message.writeTo(new OutputStream(){
+			@Override
+			public void write(int b) throws IOException {
+				total.value++;
+			}
+		});
+	    IProgress progress = (IProgress) session.getProperties()
+			.get("mail." + name + ".progress");
 	    if (chunkSize > 0 && supportsExtension("CHUNKING")) {
 		/*
 		 * Use BDAT to send the data in chunks.
@@ -1310,12 +1320,34 @@ public class SMTPTransport extends Transport {
 		 * from the message content, and b) the message content is
 		 * encoded before we even know that we can use BDAT.
 		 */
-		this.message.writeTo(bdat(), ignoreList);
+		this.message.writeTo(new FilterOutputStream(bdat()) {
+			private int size = 0;
+
+			@Override
+			public void write(int b) throws IOException {
+				super.write(b);
+				size++;
+				if (progress != null && (size % 1024) == 0)
+					progress.report(size, total.value);
+			}
+		}, ignoreList);
 		finishBdat();
 	    } else {
-		this.message.writeTo(data(), ignoreList);
+		this.message.writeTo(new FilterOutputStream(data()) {
+			private int size = 0;
+
+			@Override
+			public void write(int b) throws IOException {
+				super.write(b);
+				size++;
+				if (progress != null && (size % 1024) == 0)
+					progress.report(size, total.value);
+			}
+		}, ignoreList);
 		finishData();
 	    }
+	    if (progress != null)
+			progress.finished();
 	    if (sendPartiallyFailed) {
 		// throw the exception,
 		// fire TransportEvent.MESSAGE_PARTIALLY_DELIVERED event
@@ -1377,6 +1409,12 @@ public class SMTPTransport extends Transport {
 	sendMessageEnd();
     }
 
+    public interface IProgress {
+		void report(int size, int total);
+
+		void finished();
+	}
+
     /**
      * The send failed, fix the address arrays to report the failure correctly.
      */
diff --git a/app/src/main/java/eu/faircode/email/EmailService.java b/app/src/main/java/eu/faircode/email/EmailService.java
index fb413ee1bb..1c6f3afdf6 100644
--- a/app/src/main/java/eu/faircode/email/EmailService.java
+++ b/app/src/main/java/eu/faircode/email/EmailService.java
@@ -26,7 +26,6 @@ import android.content.Context;
 import android.content.SharedPreferences;
 import android.net.ConnectivityManager;
 import android.net.Network;
-import android.net.NetworkInfo;
 import android.os.Build;
 import android.os.ParcelFileDescriptor;
 import android.security.KeyChain;
@@ -301,6 +300,10 @@ public class EmailService implements AutoCloseable {
         properties.put("mail." + protocol + ".dsn.notify", what);
     }
 
+    void setProgress(SMTPTransport.IProgress listener) {
+        properties.put("mail." + protocol + ".progress", listener);
+    }
+
     void setListener(StoreListener listener) {
         this.listener = listener;
     }
diff --git a/app/src/main/java/eu/faircode/email/ServiceSend.java b/app/src/main/java/eu/faircode/email/ServiceSend.java
index 5b28bbc189..b988ae521b 100644
--- a/app/src/main/java/eu/faircode/email/ServiceSend.java
+++ b/app/src/main/java/eu/faircode/email/ServiceSend.java
@@ -32,6 +32,7 @@ import android.net.Network;
 import android.net.NetworkCapabilities;
 import android.net.NetworkRequest;
 import android.os.PowerManager;
+import android.os.SystemClock;
 import android.text.TextUtils;
 
 import androidx.annotation.NonNull;
@@ -41,6 +42,7 @@ import androidx.lifecycle.Observer;
 import androidx.preference.PreferenceManager;
 
 import com.sun.mail.smtp.SMTPSendFailedException;
+import com.sun.mail.smtp.SMTPTransport;
 
 import java.io.File;
 import java.io.FileNotFoundException;
@@ -67,6 +69,7 @@ public class ServiceSend extends ServiceBase implements SharedPreferences.OnShar
     private TupleUnsent lastUnsent = null;
     private Network lastActive = null;
     private boolean lastSuitable = false;
+    private int lastProgress = -1;
 
     private TwoStateOwner owner;
     private PowerManager.WakeLock wlOutbox;
@@ -76,6 +79,7 @@ public class ServiceSend extends ServiceBase implements SharedPreferences.OnShar
 
     private static final int RETRY_MAX = 3;
     private static final int CONNECTIVITY_DELAY = 5000; // milliseconds
+    private static final int PROGRESS_UPDATE_INTERVAL = 1000; // milliseconds
 
     static final int PI_SEND = 1;
 
@@ -232,6 +236,8 @@ public class ServiceSend extends ServiceBase implements SharedPreferences.OnShar
             builder.setSubText(getString(R.string.title_notification_idle));
         if (!lastSuitable)
             builder.setSubText(getString(R.string.title_notification_waiting));
+        if (lastProgress >= 0)
+            builder.setProgress(100, lastProgress, false);
 
         return builder;
     }
@@ -514,6 +520,9 @@ public class ServiceSend extends ServiceBase implements SharedPreferences.OnShar
             db.message().setMessageLastAttempt(message.id, message.last_attempt);
         }
 
+        NotificationManager nm =
+                (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
+
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
         boolean reply_move = prefs.getBoolean("reply_move", false);
         boolean debug = prefs.getBoolean("debug", false);
@@ -675,6 +684,30 @@ public class ServiceSend extends ServiceBase implements SharedPreferences.OnShar
             String via = "via " + ident.host + "/" + ident.user +
                     " to " + (to == null ? null : TextUtils.join(", ", to));
 
+            iservice.setProgress(new SMTPTransport.IProgress() {
+                private int progress = -1;
+                private long last = SystemClock.elapsedRealtime();
+
+                @Override
+                public void report(int size, int total) {
+                    int p = (total == 0 ? 0 : 100 * size / total);
+                    if (p > progress) {
+                        progress = p;
+                        long now = SystemClock.elapsedRealtime();
+                        if (now > last + PROGRESS_UPDATE_INTERVAL) {
+                            last = now;
+                            lastProgress = progress;
+                            nm.notify(NotificationHelper.NOTIFICATION_SEND, getNotificationService().build());
+                        }
+                    }
+                }
+
+                @Override
+                public void finished() {
+                    lastProgress = -1;
+                }
+            });
+
             // Send message
             EntityLog.log(this, "Sending " + via);
             start = new Date().getTime();
@@ -703,6 +736,10 @@ public class ServiceSend extends ServiceBase implements SharedPreferences.OnShar
 
             throw ex;
         } finally {
+            if (lastProgress >= 0) {
+                lastProgress = -1;
+                nm.notify(NotificationHelper.NOTIFICATION_SEND, getNotificationService().build());
+            }
             db.identity().setIdentityState(ident.id, null);
         }
 
@@ -745,8 +782,6 @@ public class ServiceSend extends ServiceBase implements SharedPreferences.OnShar
             db.endTransaction();
         }
 
-        NotificationManager nm =
-                (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
         nm.cancel("send:" + message.id, NotificationHelper.NOTIFICATION_TAGGED);
 
         // Check sent message