diff --git a/de.srsoftware.cal.api/build.gradle.kts b/de.srsoftware.cal.api/build.gradle.kts
index cd74b64..871543f 100644
--- a/de.srsoftware.cal.api/build.gradle.kts
+++ b/de.srsoftware.cal.api/build.gradle.kts
@@ -1,4 +1,5 @@
 description = "OpenCloudCal : API"
 
 dependencies {
+    implementation("de.srsoftware:tools.util:1.1.1")
 }
diff --git a/de.srsoftware.cal.api/src/main/java/de/srsoftware/cal/api/Appointment.java b/de.srsoftware.cal.api/src/main/java/de/srsoftware/cal/api/Appointment.java
index 0517ae8..00add6c 100644
--- a/de.srsoftware.cal.api/src/main/java/de/srsoftware/cal/api/Appointment.java
+++ b/de.srsoftware.cal.api/src/main/java/de/srsoftware/cal/api/Appointment.java
@@ -60,6 +60,13 @@ public interface Appointment {
 	 */
 	Set<String> tags();
 
+
+	/**
+	 * the title of the appointment
+	 * @return the title
+	 */
+	String title();
+
 	/**
 	 * set of Links that point to related information
 	 * @return set of links
diff --git a/de.srsoftware.cal.api/src/main/java/de/srsoftware/cal/api/Importer.java b/de.srsoftware.cal.api/src/main/java/de/srsoftware/cal/api/Importer.java
index ab98ae3..463eda4 100644
--- a/de.srsoftware.cal.api/src/main/java/de/srsoftware/cal/api/Importer.java
+++ b/de.srsoftware.cal.api/src/main/java/de/srsoftware/cal/api/Importer.java
@@ -1,8 +1,9 @@
 /* © SRSoftware 2024 */
 package de.srsoftware.cal.api;
 
+import de.srsoftware.tools.Result;
 import java.io.IOException;
-import java.util.List;
+import java.util.stream.Stream;
 
 /**
  * Instances of this class can be used to read Appointments from various sources
@@ -18,5 +19,5 @@ public interface Importer {
 	 * get the list of appointments from the source associated with this importer
 	 * @return a list of appointments
 	 */
-	List<Appointment> fetch() throws IOException;
+	Stream<Result<Appointment>> fetch() throws IOException;
 }
diff --git a/de.srsoftware.cal.app/build.gradle.kts b/de.srsoftware.cal.app/build.gradle.kts
index 01c6283..935fcef 100644
--- a/de.srsoftware.cal.app/build.gradle.kts
+++ b/de.srsoftware.cal.app/build.gradle.kts
@@ -3,4 +3,5 @@ description = "OpenCloudCal : Application"
 dependencies {
     implementation(project(":de.srsoftware.cal.api"))
     implementation(project(":de.srsoftware.cal.importer"))
+    implementation("de.srsoftware:tools.util:1.1.1")
 }
diff --git a/de.srsoftware.cal.app/src/main/java/de/srsoftware/cal/app/Application.java b/de.srsoftware.cal.app/src/main/java/de/srsoftware/cal/app/Application.java
index 9729a43..2848d4f 100644
--- a/de.srsoftware.cal.app/src/main/java/de/srsoftware/cal/app/Application.java
+++ b/de.srsoftware.cal.app/src/main/java/de/srsoftware/cal/app/Application.java
@@ -1,12 +1,23 @@
 /* © SRSoftware 2024 */
 package de.srsoftware.cal.app;
 
+import de.srsoftware.cal.api.Appointment;
 import de.srsoftware.cal.importer.JenaRosenkeller;
+import de.srsoftware.tools.Payload;
 import java.io.IOException;
 
 public class Application {
 	public static void main(String[] args) throws IOException {
-		var rosenkeller = new JenaRosenkeller();
-		rosenkeller.fetch();
+		var rosenkeller	 = new JenaRosenkeller();
+		var appointments = rosenkeller.fetch();
+		appointments.forEach(res -> {
+			System.out.printf("class: %s%n", res.getClass());
+			if (res instanceof Payload<Appointment> payload) {
+				System.out.printf("payload: %s%n", payload.get().getClass());
+				System.out.println(payload.get());
+			} else {
+				System.err.println(res);
+			}
+		});
 	}
 }
diff --git a/de.srsoftware.cal.importer/build.gradle.kts b/de.srsoftware.cal.importer/build.gradle.kts
index 1456989..91dda1d 100644
--- a/de.srsoftware.cal.importer/build.gradle.kts
+++ b/de.srsoftware.cal.importer/build.gradle.kts
@@ -3,6 +3,6 @@ description = "OpenCloudCal : Importers"
 dependencies {
     implementation(project(":de.srsoftware.cal.api"))
     implementation("de.srsoftware:tools.optionals:1.0.0")
-    implementation("de.srsoftware:tools.util:1.1.0")
-    implementation("de.srsoftware:tools.web:1.2.1")
+    implementation("de.srsoftware:tools.util:1.1.1")
+    implementation("de.srsoftware:tools.web:1.2.2")
 }
diff --git a/de.srsoftware.cal.importer/src/main/java/de/srsoftware/cal/importer/JenaRosenkeller.java b/de.srsoftware.cal.importer/src/main/java/de/srsoftware/cal/importer/JenaRosenkeller.java
index 5304393..c310974 100644
--- a/de.srsoftware.cal.importer/src/main/java/de/srsoftware/cal/importer/JenaRosenkeller.java
+++ b/de.srsoftware.cal.importer/src/main/java/de/srsoftware/cal/importer/JenaRosenkeller.java
@@ -1,59 +1,192 @@
 /* © SRSoftware 2024 */
 package de.srsoftware.cal.importer;
 
-import static de.srsoftware.tools.Optionals.nullable;
 import static java.util.Optional.empty;
 import static java.util.function.Predicate.not;
 
-import de.srsoftware.cal.api.Appointment;
-import de.srsoftware.cal.api.Importer;
+import de.srsoftware.cal.api.*;
+import de.srsoftware.tools.Error;
 import de.srsoftware.tools.Payload;
+import de.srsoftware.tools.Result;
 import de.srsoftware.tools.Tag;
 import de.srsoftware.tools.XMLParser;
 import java.io.IOException;
+import java.io.InputStream;
 import java.net.MalformedURLException;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.net.URL;
+import java.time.LocalDateTime;
 import java.util.List;
 import java.util.Optional;
+import java.util.Set;
 import java.util.stream.Stream;
 
 public class JenaRosenkeller implements Importer {
+	private static class EmptyAppointment implements Appointment {
+		@Override
+		public Set<Attachment> attachments() {
+			return Set.of();
+		}
+
+		@Override
+		public Optional<Coords> coords() {
+			return empty();
+		}
+
+		@Override
+		public String description() {
+			return null;
+		}
+
+		@Override
+		public Optional<LocalDateTime> end() {
+			return empty();
+		}
+
+		@Override
+		public long id() {
+			return 0;
+		}
+
+		@Override
+		public String location() {
+			return null;
+		}
+
+		@Override
+		public LocalDateTime start() {
+			return null;
+		}
+
+		@Override
+		public Set<String> tags() {
+			return Set.of();
+		}
+
+		@Override
+		public String title() {
+			return null;
+		}
+
+		@Override
+		public String toString() {
+			return "%s (%s)".formatted(title(), EmptyAppointment.class.getSimpleName());
+		}
+
+		@Override
+		public Set<Link> urls() {
+			return Set.of();
+		}
+	}
+
 	@Override
 	public String description() {
 		return "Events von der Seite rosenkeller.org importieren";
 	}
 
 	@Override
-	public List<Appointment> fetch() throws IOException {
-		var url     = "https://rosenkeller.org/de/programm";
-		var listUrl = url(url);
-		if (listUrl.isEmpty()) throw new RuntimeException("Failed to fetch %s".formatted(url));
-
-		var input  = listUrl.get().openConnection().getInputStream();
-		input      = XMLParser.preload(input);
-		var result = XMLParser.parse(input);
-		input.close();
-		List<Appointment> appointments = nullable(result)  //
-				     .filter(o -> o instanceof Payload<Tag>)
-				     .map(o -> (Payload<Tag>)o)
-				     .map(Payload::get)
-				     .stream()
-				     .flatMap(JenaRosenkeller::findEventUrls)
-				     .map(JenaRosenkeller::url)
-				     .filter(Optional::isPresent)
-				     .map(Optional::get)
-				     .map(JenaRosenkeller::loadEvent)
-				     .filter(Optional::isPresent)
-				     .map(Optional::get)
-				     .toList();
-
-		System.out.println(appointments);
-		return appointments;
+	public Stream<Result<Appointment>> fetch() throws IOException {
+		var	       url    = Payload.of("https://rosenkeller.org/de/programm");
+		Stream<Result<String>> stream = url(url)
+				    .map(JenaRosenkeller::open)	 //
+				    .map(JenaRosenkeller::preload)
+				    .map(JenaRosenkeller::parse)
+				    .map(JenaRosenkeller::findEventUrls)
+				    .stream();
+		return stream  //
+		    .map(JenaRosenkeller::url)
+		    .map(JenaRosenkeller::open)
+		    .map(JenaRosenkeller::preload)
+		    .map(JenaRosenkeller::parse)
+		    .map(JenaRosenkeller::loadEvent);
+	}
+
+	private static Result<List<String>> findEventUrls(Result<Tag> tagResult) {
+		return switch (tagResult) {
+			case Payload<Tag> payload -> {
+				List<String> urls = payload // find tag with event-id
+						.get()
+						.find("id", val -> val.startsWith("event-"))
+						.stream()
+						.map(t -> t.find("class", "ect-event-url"::equals))
+						.flatMap(List::stream)
+						.map(t -> t.get("href"))
+						.toList();
+				yield Payload.of(urls);
+			}
+			case Error<Tag> error -> error.transform();
+			default -> Error.format("Invalid parameter: %s", tagResult.getClass().getSimpleName());
+		};
+	}
+
+	private static Result<Tag> parse(Result<InputStream> inputStream) {
+		return switch (inputStream) {
+			case Payload<InputStream> payload -> XMLParser.parse(payload.get());
+			case Error<InputStream> error -> error.transform();
+			default -> Error.of("Invalid parameter: %s".formatted(inputStream.getClass().getSimpleName()));
+		};
+	}
+
+	private static Result<InputStream> preload(Result<InputStream> inputStream) {
+		switch (inputStream){
+			case Payload<InputStream> payload:
+				try {
+					return Payload.of(XMLParser.preload(payload.get()));
+				} catch (IOException e) {
+					return Error.of("Failed to buffer data from %s".formatted(payload), e);
+				}
+			case Error<InputStream> error:
+				return error.transform();
+			default:
+				return Error.format("Invalid parameter: %s", inputStream.getClass().getSimpleName());
+		}
 	}
 
-	private static Optional<Appointment> loadEvent(URL url) {
+	private static Result<InputStream> open(Result<URL> url) {
+		switch (url) {
+			case Payload<URL> payload:
+				try {
+					return Payload.of(payload.get().openConnection().getInputStream());
+				} catch (IOException e) {
+					return Error.of("Failed to open %s".formatted(payload), e);
+				}
+			case Error<URL> error:
+				return error.transform();
+			default:
+				return Error.format("Invalid parameter: %s", url.getClass().getSimpleName());
+		}
+	}
+
+	private static Result<Appointment> loadEvent(Result<Tag> domResult) {
+		switch (domResult) {
+			case Payload<Tag> payload:
+				var	 tag   = payload.get();
+				Optional<String> title = tag.find("class", s -> s.endsWith("single-event-title"))  //
+					             .stream()
+					             .map(Tag::children)
+					             .filter(not(List::isEmpty))
+					             .map(List::getFirst)
+					             .map(Tag::toString)
+					             .findAny();
+				if (title.isPresent()) {
+					var appointment = new EmptyAppointment() {
+						@Override
+						public String title() {
+							return title.get();
+						}
+					};
+					return Payload.of(appointment);
+				}
+				return Error.of("Could not find appointment title");
+			case Error<Tag> err:
+				return err.transform();
+			default:
+				return Error.format("Invalid parameter: %s", domResult.getClass().getSimpleName());
+		}
+	}
+
+	private static Optional<Appointment> nope(URL url) {
 		try {
 			var input  = url.openConnection().getInputStream();
 			input      = XMLParser.preload(input);
@@ -76,16 +209,19 @@ public class JenaRosenkeller implements Importer {
 		}
 	}
 
-	private static Stream<String> findEventUrls(Tag tag) {
-		return tag.find("id", val -> val.startsWith("event-")).stream().map(t -> t.find("class", "ect-event-url" ::equals)).flatMap(List::stream).map(t -> t.get("href"));
-	}
-
-	private static Optional<URL> url(String url) {
-		try {
-			return Optional.of(new URI(url).toURL());
-		} catch (MalformedURLException | URISyntaxException e) {
-			e.printStackTrace();
-			return empty();
+	private static Result<URL> url(Result<String> urls) {
+		switch (urls) {
+			case Payload<String> payload:
+				var url = payload.get();
+				try {
+					return Payload.of(new URI(url).toURL());
+				} catch (MalformedURLException | URISyntaxException e) {
+					return Error.of("Failed to create URL of %s".formatted(url), e);
+				}
+			case Error<String> err:
+				return err.transform();
+			default:
+				return Error.format("Invalid parameter: %s", urls.getClass().getSimpleName());
 		}
 	}
 }
\ No newline at end of file
diff --git a/doc/database.dia b/doc/database.dia
index be90534..a85241f 100644
--- a/doc/database.dia
+++ b/doc/database.dia
@@ -88,6 +88,7 @@
       </dia:composite>
     </dia:attribute>
   </dia:diagramdata>
+  <dia:layer name="Hintergrund" visible="true" connectable="false"/>
   <dia:layer name="Hintergrund" visible="true" connectable="true" active="true">
     <dia:object type="Flowchart - Box" version="0" id="O0">
       <dia:attribute name="obj_pos">
@@ -181,13 +182,13 @@
     </dia:object>
     <dia:object type="Flowchart - Box" version="0" id="O2">
       <dia:attribute name="obj_pos">
-        <dia:point val="11,9"/>
+        <dia:point val="11,11"/>
       </dia:attribute>
       <dia:attribute name="obj_bb">
-        <dia:rectangle val="10.95,8.95;16.05,11.05"/>
+        <dia:rectangle val="10.95,10.95;16.05,13.05"/>
       </dia:attribute>
       <dia:attribute name="elem_corner">
-        <dia:point val="11,9"/>
+        <dia:point val="11,11"/>
       </dia:attribute>
       <dia:attribute name="elem_width">
         <dia:real val="5"/>
@@ -213,7 +214,7 @@
             <dia:real val="0.80000000000000004"/>
           </dia:attribute>
           <dia:attribute name="pos">
-            <dia:point val="13.5,10.195"/>
+            <dia:point val="13.5,12.195"/>
           </dia:attribute>
           <dia:attribute name="color">
             <dia:color val="#000000ff"/>
@@ -226,13 +227,13 @@
     </dia:object>
     <dia:object type="Flowchart - Box" version="0" id="O3">
       <dia:attribute name="obj_pos">
-        <dia:point val="11,11"/>
+        <dia:point val="11,13"/>
       </dia:attribute>
       <dia:attribute name="obj_bb">
-        <dia:rectangle val="10.95,10.95;16.05,13.05"/>
+        <dia:rectangle val="10.95,12.95;16.05,15.05"/>
       </dia:attribute>
       <dia:attribute name="elem_corner">
-        <dia:point val="11,11"/>
+        <dia:point val="11,13"/>
       </dia:attribute>
       <dia:attribute name="elem_width">
         <dia:real val="5"/>
@@ -258,7 +259,7 @@
             <dia:real val="0.80000000000000004"/>
           </dia:attribute>
           <dia:attribute name="pos">
-            <dia:point val="13.5,12.195"/>
+            <dia:point val="13.5,14.195"/>
           </dia:attribute>
           <dia:attribute name="color">
             <dia:color val="#000000ff"/>
@@ -271,13 +272,13 @@
     </dia:object>
     <dia:object type="Flowchart - Box" version="0" id="O4">
       <dia:attribute name="obj_pos">
-        <dia:point val="11,13"/>
+        <dia:point val="11,15"/>
       </dia:attribute>
       <dia:attribute name="obj_bb">
-        <dia:rectangle val="10.95,12.95;16.05,15.05"/>
+        <dia:rectangle val="10.95,14.95;16.05,17.05"/>
       </dia:attribute>
       <dia:attribute name="elem_corner">
-        <dia:point val="11,13"/>
+        <dia:point val="11,15"/>
       </dia:attribute>
       <dia:attribute name="elem_width">
         <dia:real val="5"/>
@@ -303,7 +304,7 @@
             <dia:real val="0.80000000000000004"/>
           </dia:attribute>
           <dia:attribute name="pos">
-            <dia:point val="13.5,14.195"/>
+            <dia:point val="13.5,16.195"/>
           </dia:attribute>
           <dia:attribute name="color">
             <dia:color val="#000000ff"/>
@@ -316,13 +317,13 @@
     </dia:object>
     <dia:object type="Flowchart - Box" version="0" id="O5">
       <dia:attribute name="obj_pos">
-        <dia:point val="11,15"/>
+        <dia:point val="11,17"/>
       </dia:attribute>
       <dia:attribute name="obj_bb">
-        <dia:rectangle val="10.95,14.95;16.05,17.05"/>
+        <dia:rectangle val="10.95,16.95;16.05,19.05"/>
       </dia:attribute>
       <dia:attribute name="elem_corner">
-        <dia:point val="11,15"/>
+        <dia:point val="11,17"/>
       </dia:attribute>
       <dia:attribute name="elem_width">
         <dia:real val="5"/>
@@ -348,7 +349,7 @@
             <dia:real val="0.80000000000000004"/>
           </dia:attribute>
           <dia:attribute name="pos">
-            <dia:point val="13.5,16.195"/>
+            <dia:point val="13.5,18.195"/>
           </dia:attribute>
           <dia:attribute name="color">
             <dia:color val="#000000ff"/>
@@ -361,13 +362,13 @@
     </dia:object>
     <dia:object type="Flowchart - Box" version="0" id="O6">
       <dia:attribute name="obj_pos">
-        <dia:point val="11,17"/>
+        <dia:point val="11,19"/>
       </dia:attribute>
       <dia:attribute name="obj_bb">
-        <dia:rectangle val="10.95,16.95;16.05,19.05"/>
+        <dia:rectangle val="10.95,18.95;16.05,21.05"/>
       </dia:attribute>
       <dia:attribute name="elem_corner">
-        <dia:point val="11,17"/>
+        <dia:point val="11,19"/>
       </dia:attribute>
       <dia:attribute name="elem_width">
         <dia:real val="5"/>
@@ -393,7 +394,7 @@
             <dia:real val="0.80000000000000004"/>
           </dia:attribute>
           <dia:attribute name="pos">
-            <dia:point val="13.5,18.195"/>
+            <dia:point val="13.5,20.195"/>
           </dia:attribute>
           <dia:attribute name="color">
             <dia:color val="#000000ff"/>
@@ -1596,16 +1597,16 @@
     </dia:object>
     <dia:object type="Flowchart - Box" version="0" id="O35">
       <dia:attribute name="obj_pos">
-        <dia:point val="12,27"/>
+        <dia:point val="11.9962,27"/>
       </dia:attribute>
       <dia:attribute name="obj_bb">
-        <dia:rectangle val="11.95,26.95;16.08,29.05"/>
+        <dia:rectangle val="11.9462,26.95;16.0837,29.05"/>
       </dia:attribute>
       <dia:attribute name="elem_corner">
-        <dia:point val="12,27"/>
+        <dia:point val="11.9962,27"/>
       </dia:attribute>
       <dia:attribute name="elem_width">
-        <dia:real val="4.0300000000000002"/>
+        <dia:real val="4.0374999999999996"/>
       </dia:attribute>
       <dia:attribute name="elem_height">
         <dia:real val="2"/>
@@ -1684,5 +1685,50 @@
         </dia:composite>
       </dia:attribute>
     </dia:object>
+    <dia:object type="Flowchart - Box" version="0" id="O37">
+      <dia:attribute name="obj_pos">
+        <dia:point val="11,9"/>
+      </dia:attribute>
+      <dia:attribute name="obj_bb">
+        <dia:rectangle val="10.95,8.95;16.05,11.05"/>
+      </dia:attribute>
+      <dia:attribute name="elem_corner">
+        <dia:point val="11,9"/>
+      </dia:attribute>
+      <dia:attribute name="elem_width">
+        <dia:real val="5"/>
+      </dia:attribute>
+      <dia:attribute name="elem_height">
+        <dia:real val="2"/>
+      </dia:attribute>
+      <dia:attribute name="show_background">
+        <dia:boolean val="true"/>
+      </dia:attribute>
+      <dia:attribute name="padding">
+        <dia:real val="0.5"/>
+      </dia:attribute>
+      <dia:attribute name="text">
+        <dia:composite type="text">
+          <dia:attribute name="string">
+            <dia:string>#title#</dia:string>
+          </dia:attribute>
+          <dia:attribute name="font">
+            <dia:font family="sans" style="0" name="Helvetica"/>
+          </dia:attribute>
+          <dia:attribute name="height">
+            <dia:real val="0.80000000000000004"/>
+          </dia:attribute>
+          <dia:attribute name="pos">
+            <dia:point val="13.5,10.195"/>
+          </dia:attribute>
+          <dia:attribute name="color">
+            <dia:color val="#000000ff"/>
+          </dia:attribute>
+          <dia:attribute name="alignment">
+            <dia:enum val="1"/>
+          </dia:attribute>
+        </dia:composite>
+      </dia:attribute>
+    </dia:object>
   </dia:layer>
 </dia:diagram>