diff --git a/app/src/main/java/com/wireguard/android/ConfigEditFragment.java b/app/src/main/java/com/wireguard/android/ConfigEditFragment.java
index ebebef42..1edae9cc 100644
--- a/app/src/main/java/com/wireguard/android/ConfigEditFragment.java
+++ b/app/src/main/java/com/wireguard/android/ConfigEditFragment.java
@@ -113,18 +113,13 @@ public class ConfigEditFragment extends BaseConfigFragment {
     }
 
     private void saveConfig() {
-        final String errorMessage = localConfig.validate();
         final VpnService service = VpnService.getInstance();
-        if (errorMessage != null) {
-            Toast.makeText(getActivity(), errorMessage, Toast.LENGTH_SHORT).show();
-            return;
-        }
         try {
             if (getCurrentConfig() != null)
                 service.update(getCurrentConfig().getName(), localConfig);
             else
                 service.add(localConfig);
-        } catch (final IllegalStateException e) {
+        } catch (final IllegalArgumentException | IllegalStateException e) {
             Toast.makeText(getActivity(), e.getMessage(), Toast.LENGTH_SHORT).show();
             return;
         }
diff --git a/app/src/main/java/com/wireguard/android/VpnService.java b/app/src/main/java/com/wireguard/android/VpnService.java
index ad8eb608..0fd67136 100644
--- a/app/src/main/java/com/wireguard/android/VpnService.java
+++ b/app/src/main/java/com/wireguard/android/VpnService.java
@@ -13,6 +13,7 @@ import android.service.quicksettings.TileService;
 import android.util.Log;
 
 import com.wireguard.config.Config;
+import com.wireguard.config.Peer;
 
 import java.io.File;
 import java.io.FileOutputStream;
@@ -367,8 +368,15 @@ public class VpnService extends Service
             // When adding a config, "old file" and "new file" are the same thing.
             oldName = knownConfig != null ? knownConfig.getName() : newName;
             this.shouldConnect = shouldConnect;
+            if (newName == null || !Config.isNameValid(newName))
+                throw new IllegalArgumentException("This configuration does not have a valid name");
             if (isAddOrRename() && configurations.containsKey(newName))
-                throw new IllegalStateException("Config " + newName + " already exists");
+                throw new IllegalStateException("Configuration " + newName + " already exists");
+            if (newConfig.getInterface().getPublicKey() == null)
+                throw new IllegalArgumentException("This configuration must have a valid keypair");
+            for (final Peer peer : newConfig.getPeers())
+                if (peer.getPublicKey() == null || peer.getPublicKey().isEmpty())
+                    throw new IllegalArgumentException("Each peer must have a valid public key");
         }
 
         @Override
diff --git a/app/src/main/java/com/wireguard/config/Config.java b/app/src/main/java/com/wireguard/config/Config.java
index cb9b7ed2..2a282d09 100644
--- a/app/src/main/java/com/wireguard/config/Config.java
+++ b/app/src/main/java/com/wireguard/config/Config.java
@@ -40,7 +40,7 @@ public class Config extends BaseObservable
     public static final int NAME_MAX_LENGTH = 16;
     private static final Pattern PATTERN = Pattern.compile("^[a-zA-Z0-9_=+.-]{1,16}$");
 
-    private static boolean isNameValid(final String name) {
+    public static boolean isNameValid(final String name) {
         return name.length() <= NAME_MAX_LENGTH && PATTERN.matcher(name).matches();
     }
 
@@ -180,14 +180,6 @@ public class Config extends BaseObservable
         return sb.toString();
     }
 
-    public String validate() {
-        if (name == null || !isNameValid(name))
-            return "This configuration does not have a valid name.";
-        if (iface.getPublicKey() == null)
-            return "This configuration does not have a valid keypair.";
-        return null;
-    }
-
     @Override
     public void writeToParcel(final Parcel dest, final int flags) {
         dest.writeParcelable(iface, flags);