diff --git a/oparl-server/src/main/java/de/twomartens/oparlservice/control/OParlController.java b/oparl-server/src/main/java/de/twomartens/oparlservice/control/OParlController.java
index 068f20e..a8a137a 100644
--- a/oparl-server/src/main/java/de/twomartens/oparlservice/control/OParlController.java
+++ b/oparl-server/src/main/java/de/twomartens/oparlservice/control/OParlController.java
@@ -6,10 +6,9 @@ import de.twomartens.oparlservice.service.OParlService;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
 import lombok.extern.slf4j.Slf4j;
-import org.springframework.web.bind.annotation.GetMapping;
-import org.springframework.web.bind.annotation.PathVariable;
-import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.bind.annotation.RestController;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.*;
+import org.springframework.web.server.ResponseStatusException;
 
 import java.util.List;
 
@@ -44,7 +43,9 @@ public class OParlController {
             @Parameter(description = "body ID", example = "0")
                     String id) {
         log.info("method invoked /v1.1/body/{}", id);
-        return service.getBody(id);
+        return service.getBody(id).orElseThrow(() -> {
+            throw new ResponseStatusException(HttpStatus.NOT_FOUND, "Körperschaft mit angefragter ID existiert nicht");
+        });
     }
 
     @GetMapping("/term/{id}")
@@ -54,7 +55,9 @@ public class OParlController {
             @Parameter(description = "legislative term ID", example = "21")
                     String id) {
         log.info("method invoked /v1.1/term/{}", id);
-        return service.getLegislativeTerm(id);
+        return service.getLegislativeTerm(id).orElseThrow(() -> {
+            throw new ResponseStatusException(HttpStatus.NOT_FOUND, "Legislaturperiode mit angefragter ID existiert nicht");
+        });
     }
 
     @GetMapping("/body/{id}/organizations")
@@ -64,7 +67,9 @@ public class OParlController {
             @Parameter(description = "body ID", example = "0")
                     String id) {
         log.info("invoked method /v1.1/body/{}/organizations", id);
-        return service.getOrganizationsInBody(id);
+        return service.getOrganizationsInBody(id).orElseThrow(() -> {
+            throw new ResponseStatusException(HttpStatus.NOT_FOUND, "Keine Körperschaft mit angefragter ID existiert");
+        });
     }
 
     @GetMapping("/organization/{id}")
@@ -74,7 +79,9 @@ public class OParlController {
             @Parameter(description = "organization ID", example = "0")
                     String id) {
         log.info("invoked method /v1.1/organization/{}", id);
-        return service.getOrganization(id);
+        return service.getOrganization(id).orElseThrow(() -> {
+            throw new ResponseStatusException(HttpStatus.NOT_FOUND, "Keine Organisation mit angefragter ID existiert");
+        });
     }
 
     @GetMapping("/body/{id}/persons")
@@ -84,7 +91,9 @@ public class OParlController {
             @Parameter(description = "body ID", example = "0")
                     String id) {
         log.info("invoked method /v1.1/body/{}/persons", id);
-        return service.getPersonsInBody(id);
+        return service.getPersonsInBody(id).orElseThrow(() -> {
+            throw new ResponseStatusException(HttpStatus.NOT_FOUND, "Keine Körperschaft mit angefragter ID existiert");
+        });
     }
 
     @GetMapping("/person/{id}")
@@ -94,7 +103,9 @@ public class OParlController {
             @Parameter(description = "person ID", example = "0")
                     String id) {
         log.info("invoked method /v1.1/person/{}", id);
-        return service.getPerson(id);
+        return service.getPerson(id).orElseThrow(() -> {
+            throw new ResponseStatusException(HttpStatus.NOT_FOUND, "Keine Person mit angefragter ID existiert");
+        });
     }
 
     @GetMapping("/body/{id}/memberships")
@@ -104,7 +115,9 @@ public class OParlController {
             @Parameter(description = "body ID", example = "0")
                     String id) {
         log.info("invoked method /v1.1/body/{}/memberships", id);
-        return service.getMembershipsInBody(id);
+        return service.getMembershipsInBody(id).orElseThrow(() -> {
+            throw new ResponseStatusException(HttpStatus.NOT_FOUND, "Keine Körperschaft mit angefragter ID existiert");
+        });
     }
 
     @GetMapping("/organization/{id}/memberships")
@@ -114,7 +127,9 @@ public class OParlController {
             @Parameter(description = "organization ID", example = "0")
                     String id) {
         log.info("invoked method /v1.1/organization/{}/memberships", id);
-        return service.getMembershipsInOrganization(id);
+        return service.getMembershipsInOrganization(id).orElseThrow(() -> {
+            throw new ResponseStatusException(HttpStatus.NOT_FOUND, "Keine Organisation mit angefragter ID existiert");
+        });
     }
 
     @GetMapping("/membership/{id}")
@@ -124,7 +139,9 @@ public class OParlController {
             @Parameter(description = "membership ID", example = "0")
                     String id) {
         log.info("invoked method /v1.1/membership/{}", id);
-        return service.getMembership(id);
+        return service.getMembership(id).orElseThrow(() -> {
+            throw new ResponseStatusException(HttpStatus.NOT_FOUND, "Keine Mitgliedschaft mit angefragter ID existiert");
+        });
     }
 
     @GetMapping("/body/{id}/meetings")
@@ -134,7 +151,9 @@ public class OParlController {
             @Parameter(description = "body ID", example = "0")
                     String id) {
         log.info("invoked method /v1.1/body/{}/meetings", id);
-        return service.getMeetingsInBody(id);
+        return service.getMeetingsInBody(id).orElseThrow(() -> {
+            throw new ResponseStatusException(HttpStatus.NOT_FOUND, "Keine Körperschaft mit angefragter ID existiert");
+        });
     }
 
     @GetMapping("/organization/{id}/meetings")
@@ -144,7 +163,9 @@ public class OParlController {
             @Parameter(description = "organization ID", example = "0")
                     String id) {
         log.info("invoked method /v1.1/organization/{}/meetings", id);
-        return service.getMeetingsInOrganization(id);
+        return service.getMeetingsInOrganization(id).orElseThrow(() -> {
+            throw new ResponseStatusException(HttpStatus.NOT_FOUND, "Keine Organisation mit angefragter ID existiert");
+        });
     }
 
     @GetMapping("/meeting/{id}")
@@ -154,7 +175,9 @@ public class OParlController {
             @Parameter(description = "meeting ID", example = "0")
                     String id) {
         log.info("invoked method /v1.1/meeting/{}", id);
-        return service.getMeeting(id);
+        return service.getMeeting(id).orElseThrow(() -> {
+            throw new ResponseStatusException(HttpStatus.NOT_FOUND, "Keine Sitzung mit angefragter ID existiert");
+        });
     }
 
     @GetMapping("/agendaItem/{id}")
@@ -164,6 +187,17 @@ public class OParlController {
             @Parameter(description = "agendaItem ID", example = "0")
                     String id) {
         log.info("invoked method /v1.1/agendaItem/{}", id);
-        return service.getAgendaItem(id);
+        return service.getAgendaItem(id).orElseThrow(() -> {
+            throw new ResponseStatusException(HttpStatus.NOT_FOUND, "Kein Tagesordnungspunkt mit angefragter ID existiert");
+        });
+    }
+
+    @ExceptionHandler({ResponseStatusException.class})
+    @ResponseStatus(HttpStatus.NOT_FOUND)
+    public ErrorObject notFound(ResponseStatusException exception) {
+        return ErrorObject.builder()
+                .message(exception.getReason())
+                .debug(exception.getLocalizedMessage())
+                .build();
     }
 }
diff --git a/oparl-server/src/main/java/de/twomartens/oparlservice/entity/ErrorObject.java b/oparl-server/src/main/java/de/twomartens/oparlservice/entity/ErrorObject.java
new file mode 100644
index 0000000..4b32a34
--- /dev/null
+++ b/oparl-server/src/main/java/de/twomartens/oparlservice/entity/ErrorObject.java
@@ -0,0 +1,23 @@
+package de.twomartens.oparlservice.entity;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import io.swagger.v3.oas.annotations.media.Schema;
+import lombok.*;
+
+@Builder
+@Getter
+@ToString
+@EqualsAndHashCode
+@AllArgsConstructor(access = AccessLevel.PRIVATE)
+@NoArgsConstructor(force = true, access = AccessLevel.PRIVATE)
+@JsonInclude(JsonInclude.Include.NON_NULL)
+public class ErrorObject {
+    @Schema(description = "URL to type specification")
+    private final String type = "https://schema.oparl.org/1.1/Error";
+
+    @Schema(description = "message for display to the user")
+    private final String message;
+
+    @Schema(description = "additional information about the error")
+    private final String debug;
+}
diff --git a/oparl-server/src/main/java/de/twomartens/oparlservice/service/OParlService.java b/oparl-server/src/main/java/de/twomartens/oparlservice/service/OParlService.java
index d49a5f7..1f58295 100644
--- a/oparl-server/src/main/java/de/twomartens/oparlservice/service/OParlService.java
+++ b/oparl-server/src/main/java/de/twomartens/oparlservice/service/OParlService.java
@@ -5,130 +5,74 @@ import de.twomartens.oparlservice.entity.System;
 import de.twomartens.oparlservice.entity.*;
 import org.springframework.stereotype.Service;
 
-import java.time.LocalDate;
-import java.time.ZonedDateTime;
-import java.util.List;
+import java.util.Optional;
 
 @Service
 public class OParlService {
 
     private final OParlServiceProperties properties;
-    private final Body exampleBody;
-    private final LegislativeTerm exampleTerm;
-    private final System system;
 
     public OParlService(OParlServiceProperties properties) {
         this.properties = properties;
-
-        this.exampleTerm = LegislativeTerm.builder()
-                .id(properties.getUrl() + "/v1.1/term/21")
-                .type("https://schema.oparl.org/1.1/LegislativeTerm")
-                .body(properties.getUrl() + "/v1.1/body/0")
-                .name("21. Wahlperiode")
-                .startDate(LocalDate.parse("2019-05-27"))
-                .endDate(LocalDate.parse("2024-05-26"))
-                .created(ZonedDateTime.now())
-                .modified(ZonedDateTime.now())
-                .build();
-        this.exampleBody = Body.builder()
-                .id(properties.getUrl() + "/v1.1/body/0")
-                .type("https://schema.oparl.org/1.1/Body")
-                .created(ZonedDateTime.now())
-                .modified(ZonedDateTime.now())
-                .shortName("Hamburg")
-                .name("Bezirk Eimsbüttel")
-                .system(properties.getUrl() + "/v1.1")
-                .legislativeTerm(List.of(exampleTerm))
-                .website("https://www.hamburg.de/eimsbuettel")
-                .ags("02000000")
-                .rgs("020000000000")
-                .equivalent(List.of("http://dbpedia.org/page/Eimsb%C3%BCttel", "http://d-nb.info/1208293575"))
-                .organization(properties.getUrl() + "/v1.1/organizations/0")
-                .person(properties.getUrl() + "/v1.1/persons/0")
-                .meeting(properties.getUrl() + "/v1.1/meetings/0")
-                .paper(properties.getUrl() + "/v1.1/papers/0")
-                .agendaItem(properties.getUrl() + "/v1.1/agendaItems/0")
-                .consultation(properties.getUrl() + "/v1.1/consultations/0")
-                .file(properties.getUrl() + "/v1.1/files/0")
-                .locationList(properties.getUrl() + "/v1.1/locations/0")
-                .legislativeTermList(properties.getUrl() + "/v1.1/terms")
-                .membership(properties.getUrl() + "/v1.1/memberships/0")
-                .classification("Bezirk")
-                .build();
-        this.system = System.builder()
-                .id(properties.getUrl() + "/v1.1")
-                .type("https://schema.oparl.org/1.1/System")
-                .license("https://www.govdata.de/dl-de/by-2-0")
-                .created(ZonedDateTime.now())
-                .modified(ZonedDateTime.now())
-                .oparlVersion("https://schema.oparl.org/1.1/")
-                .name("OParl interface for ALLRIS of Hamburg Eimsbüttel")
-                .contactEmail("github@2martens.de")
-                .contactName("Jim Martens")
-                .website("https://sitzungsdienst-eimsbuettel.hamburg.de/bi/")
-                .vendor("https://2martens.de")
-                .product("https://git.2martens.de/2martens/oparl-service")
-                .body(properties.getUrl() + "/bodies")
-                .build();
     }
 
-    public AgendaItem getAgendaItem(String id) {
-        return null;
+    public Optional<AgendaItem> getAgendaItem(String id) {
+        return Optional.empty();
     }
 
     public ObjectList<Body> getBodies() {
         return null;
     }
 
-    public Body getBody(String id) {
-        return exampleBody;
+    public Optional<Body> getBody(String id) {
+        return Optional.empty();
     }
 
-    public LegislativeTerm getLegislativeTerm(String id) {
-        return exampleTerm;
+    public Optional<LegislativeTerm> getLegislativeTerm(String id) {
+        return Optional.empty();
     }
 
-    public Meeting getMeeting(String id) {
-        return null;
+    public Optional<Meeting> getMeeting(String id) {
+        return Optional.empty();
     }
 
-    public ObjectList<Meeting> getMeetingsInBody(String bodyID) {
-        return null;
+    public Optional<ObjectList<Meeting>> getMeetingsInBody(String bodyID) {
+        return Optional.empty();
     }
 
-    public ObjectList<Meeting> getMeetingsInOrganization(String organizationID) {
-        return null;
+    public Optional<ObjectList<Meeting>> getMeetingsInOrganization(String organizationID) {
+        return Optional.empty();
     }
 
-    public Membership getMembership(String id) {
-        return null;
+    public Optional<Membership> getMembership(String id) {
+        return Optional.empty();
     }
 
-    public ObjectList<Membership> getMembershipsInBody(String bodyID) {
-        return null;
+    public Optional<ObjectList<Membership>> getMembershipsInBody(String bodyID) {
+        return Optional.empty();
     }
 
-    public ObjectList<Membership> getMembershipsInOrganization(String organizationID) {
-        return null;
+    public Optional<ObjectList<Membership>> getMembershipsInOrganization(String organizationID) {
+        return Optional.empty();
     }
 
-    public ObjectList<Organization> getOrganizationsInBody(String bodyID) {
-        return null;
+    public Optional<ObjectList<Organization>> getOrganizationsInBody(String bodyID) {
+        return Optional.empty();
     }
 
-    public Organization getOrganization(String id) {
-        return null;
+    public Optional<Organization> getOrganization(String id) {
+        return Optional.empty();
     }
 
-    public ObjectList<Person> getPersonsInBody(String bodyID) {
-        return null;
+    public Optional<ObjectList<Person>> getPersonsInBody(String bodyID) {
+        return Optional.empty();
     }
 
-    public Person getPerson(String id) {
-        return null;
+    public Optional<Person> getPerson(String id) {
+        return Optional.empty();
     }
 
     public System getSystem() {
-        return system;
+        return null;
     }
 }
diff --git a/oparl-server/src/test/java/de/twomartens/oparlservice/control/OParlControllerTest.java b/oparl-server/src/test/java/de/twomartens/oparlservice/control/OParlControllerTest.java
index e0b02cf..a0e999b 100644
--- a/oparl-server/src/test/java/de/twomartens/oparlservice/control/OParlControllerTest.java
+++ b/oparl-server/src/test/java/de/twomartens/oparlservice/control/OParlControllerTest.java
@@ -19,6 +19,7 @@ import java.time.LocalDate;
 import java.time.ZonedDateTime;
 import java.util.Collections;
 import java.util.List;
+import java.util.Optional;
 
 @WebMvcTest(OParlController.class)
 class OParlControllerTest {
@@ -50,6 +51,29 @@ class OParlControllerTest {
         initializeTestValues();
     }
 
+    @Test
+    void shouldReturnErrorObject_WhenInvalidIDPassed() throws Exception {
+        BDDMockito.given(service.getBody("2"))
+                .willReturn(Optional.empty());
+
+        BDDMockito.given(service.getMembershipsInBody("2"))
+                .willReturn(Optional.empty());
+
+        mvc.perform(MockMvcRequestBuilders.get("/v1.1/body/2")
+                .contentType(MediaType.APPLICATION_JSON))
+                .andExpect(MockMvcResultMatchers.status().is4xxClientError())
+                .andExpect(MockMvcResultMatchers.jsonPath("$", Matchers.aMapWithSize(3)))
+                .andExpect(MockMvcResultMatchers.jsonPath("$.type", Matchers.equalTo("https://schema.oparl.org/1.1/Error")))
+                .andReturn();
+
+        mvc.perform(MockMvcRequestBuilders.get("/v1.1/body/2/memberships")
+                .contentType(MediaType.APPLICATION_JSON))
+                .andExpect(MockMvcResultMatchers.status().is4xxClientError())
+                .andExpect(MockMvcResultMatchers.jsonPath("$", Matchers.aMapWithSize(3)))
+                .andExpect(MockMvcResultMatchers.jsonPath("$.type", Matchers.equalTo("https://schema.oparl.org/1.1/Error")))
+                .andReturn();
+    }
+
     @Test
     void shouldReturnSystemInfo() throws Exception {
         BDDMockito.given(service.getSystem())
@@ -88,7 +112,7 @@ class OParlControllerTest {
     @Test
     void shouldReturnBody() throws Exception {
         BDDMockito.given(service.getBody("0"))
-                .willReturn(testBody);
+                .willReturn(Optional.of(testBody));
 
         mvc.perform(MockMvcRequestBuilders.get("/v1.1/body/0")
                 .contentType(MediaType.APPLICATION_JSON))
@@ -102,7 +126,7 @@ class OParlControllerTest {
     @Test
     void shouldReturnLegislativeTerm() throws Exception {
         BDDMockito.given(service.getLegislativeTerm("21"))
-                .willReturn(testTerm);
+                .willReturn(Optional.of(testTerm));
 
         mvc.perform(MockMvcRequestBuilders.get("/v1.1/term/21")
                 .contentType(MediaType.APPLICATION_JSON))
@@ -117,7 +141,9 @@ class OParlControllerTest {
     @Test
     void shouldReturnOrganizationsInBody() throws Exception {
         BDDMockito.given(service.getOrganizationsInBody("0"))
-                .willReturn(ObjectList.<Organization>builder().data(List.of(testOrganization, testPartyOrganization)).pagination(testPagination).links(testLinks).build());
+                .willReturn(Optional.of(
+                        ObjectList.<Organization>builder().data(List.of(testOrganization, testPartyOrganization)).pagination(testPagination).links(testLinks).build()
+                ));
 
         mvc.perform(MockMvcRequestBuilders.get("/v1.1/body/0/organizations")
                 .contentType(MediaType.APPLICATION_JSON))
@@ -133,7 +159,7 @@ class OParlControllerTest {
     @Test
     void shouldReturnOrganization() throws Exception {
         BDDMockito.given(service.getOrganization("0"))
-                .willReturn(testOrganization);
+                .willReturn(Optional.of(testOrganization));
 
         mvc.perform(MockMvcRequestBuilders.get("/v1.1/organization/0")
                 .contentType(MediaType.APPLICATION_JSON))
@@ -147,7 +173,9 @@ class OParlControllerTest {
     @Test
     void shouldReturnPersonsInBody() throws Exception {
         BDDMockito.given(service.getPersonsInBody("0"))
-                .willReturn(ObjectList.<Person>builder().data(List.of(testPerson)).pagination(testPagination).links(testLinks).build());
+                .willReturn(Optional.of(
+                        ObjectList.<Person>builder().data(List.of(testPerson)).pagination(testPagination).links(testLinks).build()
+                ));
 
         mvc.perform(MockMvcRequestBuilders.get("/v1.1/body/0/persons")
                 .contentType(MediaType.APPLICATION_JSON))
@@ -163,7 +191,7 @@ class OParlControllerTest {
     @Test
     void shouldReturnPerson() throws Exception {
         BDDMockito.given(service.getPerson("0"))
-                .willReturn(testPerson);
+                .willReturn(Optional.of(testPerson));
 
         mvc.perform(MockMvcRequestBuilders.get("/v1.1/person/0")
                 .contentType(MediaType.APPLICATION_JSON))
@@ -177,7 +205,9 @@ class OParlControllerTest {
     @Test
     void shouldReturnMembershipsInBody() throws Exception {
         BDDMockito.given(service.getMembershipsInBody("0"))
-                .willReturn(ObjectList.<Membership>builder().data(List.of(testMembership)).pagination(testPagination).links(testLinks).build());
+                .willReturn(Optional.of(
+                        ObjectList.<Membership>builder().data(List.of(testMembership)).pagination(testPagination).links(testLinks).build()
+                ));
 
         mvc.perform(MockMvcRequestBuilders.get("/v1.1/body/0/memberships")
                 .contentType(MediaType.APPLICATION_JSON))
@@ -193,7 +223,9 @@ class OParlControllerTest {
     @Test
     void shouldReturnMembershipsInOrganization() throws Exception {
         BDDMockito.given(service.getMembershipsInOrganization("0"))
-                .willReturn(ObjectList.<Membership>builder().data(List.of(testMembership)).pagination(testPagination).links(testLinks).build());
+                .willReturn(Optional.of(
+                        ObjectList.<Membership>builder().data(List.of(testMembership)).pagination(testPagination).links(testLinks).build()
+                ));
 
         mvc.perform(MockMvcRequestBuilders.get("/v1.1/organization/0/memberships")
                 .contentType(MediaType.APPLICATION_JSON))
@@ -209,7 +241,7 @@ class OParlControllerTest {
     @Test
     void shouldReturnMembership() throws Exception {
         BDDMockito.given(service.getMembership("0"))
-                .willReturn(testMembership);
+                .willReturn(Optional.of(testMembership));
 
         mvc.perform(MockMvcRequestBuilders.get("/v1.1/membership/0")
                 .contentType(MediaType.APPLICATION_JSON))
@@ -224,7 +256,9 @@ class OParlControllerTest {
     @Test
     void shouldReturnMeetingsInBody() throws Exception {
         BDDMockito.given(service.getMeetingsInBody("0"))
-                .willReturn(ObjectList.<Meeting>builder().data(List.of(testMeeting)).pagination(testPagination).links(testLinks).build());
+                .willReturn(Optional.of(
+                        ObjectList.<Meeting>builder().data(List.of(testMeeting)).pagination(testPagination).links(testLinks).build()
+                ));
 
         mvc.perform(MockMvcRequestBuilders.get("/v1.1/body/0/meetings")
                 .contentType(MediaType.APPLICATION_JSON))
@@ -240,7 +274,9 @@ class OParlControllerTest {
     @Test
     void shouldReturnMeetingsInOrganization() throws Exception {
         BDDMockito.given(service.getMeetingsInOrganization("0"))
-                .willReturn(ObjectList.<Meeting>builder().data(List.of(testMeeting)).pagination(testPagination).links(testLinks).build());
+                .willReturn(Optional.of(
+                        ObjectList.<Meeting>builder().data(List.of(testMeeting)).pagination(testPagination).links(testLinks).build()
+                ));
 
         mvc.perform(MockMvcRequestBuilders.get("/v1.1/organization/0/meetings")
                 .contentType(MediaType.APPLICATION_JSON))
@@ -256,7 +292,7 @@ class OParlControllerTest {
     @Test
     void shouldReturnMeeting() throws Exception {
         BDDMockito.given(service.getMeeting("0"))
-                .willReturn(testMeeting);
+                .willReturn(Optional.of(testMeeting));
 
         mvc.perform(MockMvcRequestBuilders.get("/v1.1/meeting/0")
                 .contentType(MediaType.APPLICATION_JSON))
@@ -270,7 +306,7 @@ class OParlControllerTest {
     @Test
     void shouldReturnAgendaItem() throws Exception {
         BDDMockito.given(service.getAgendaItem("0"))
-                .willReturn(testItem);
+                .willReturn(Optional.of(testItem));
 
         mvc.perform(MockMvcRequestBuilders.get("/v1.1/agendaItem/0")
                 .contentType(MediaType.APPLICATION_JSON))