diff --git a/bundles/org.openhab.core.automation.rest/src/main/java/org/openhab/core/automation/rest/internal/RuleResource.java b/bundles/org.openhab.core.automation.rest/src/main/java/org/openhab/core/automation/rest/internal/RuleResource.java
index 29a60c5dc3f..7fe1cada47c 100644
--- a/bundles/org.openhab.core.automation.rest/src/main/java/org/openhab/core/automation/rest/internal/RuleResource.java
+++ b/bundles/org.openhab.core.automation.rest/src/main/java/org/openhab/core/automation/rest/internal/RuleResource.java
@@ -214,7 +214,7 @@ public Response getByUID(@PathParam("ruleUID") @Parameter(description = "ruleUID
     @Path("/{ruleUID}")
     @Produces(MediaType.APPLICATION_JSON)
     @Operation(operationId = "deleteRule", summary = "Removes an existing rule corresponding to the given UID.", responses = {
-            @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = String.class))),
+            @ApiResponse(responseCode = "200", description = "OK"),
             @ApiResponse(responseCode = "404", description = "Rule corresponding to the given UID does not found.") })
     public Response remove(@PathParam("ruleUID") @Parameter(description = "ruleUID") String ruleUID) {
         Rule removedRule = ruleRegistry.remove(ruleUID);
diff --git a/bundles/org.openhab.core.io.rest.auth/src/main/java/org/openhab/core/io/rest/auth/internal/TokenResource.java b/bundles/org.openhab.core.io.rest.auth/src/main/java/org/openhab/core/io/rest/auth/internal/TokenResource.java
index 4590bd1665b..22bf7c2758b 100644
--- a/bundles/org.openhab.core.io.rest.auth/src/main/java/org/openhab/core/io/rest/auth/internal/TokenResource.java
+++ b/bundles/org.openhab.core.io.rest.auth/src/main/java/org/openhab/core/io/rest/auth/internal/TokenResource.java
@@ -66,6 +66,7 @@
 import org.slf4j.LoggerFactory;
 
 import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.media.ArraySchema;
 import io.swagger.v3.oas.annotations.media.Content;
 import io.swagger.v3.oas.annotations.media.Schema;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
@@ -115,7 +116,7 @@ public TokenResource(final @Reference UserRegistry userRegistry, final @Referenc
     @Produces({ MediaType.APPLICATION_JSON })
     @Consumes({ MediaType.APPLICATION_FORM_URLENCODED })
     @Operation(operationId = "getOAuthToken", summary = "Get access and refresh tokens.", responses = {
-            @ApiResponse(responseCode = "200", description = "OK"),
+            @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = TokenResponseDTO.class))),
             @ApiResponse(responseCode = "400", description = "Invalid request parameters") })
     public Response getToken(@FormParam("grant_type") String grantType, @FormParam("code") String code,
             @FormParam("redirect_uri") String redirectUri, @FormParam("client_id") String clientId,
@@ -145,7 +146,7 @@ public Response getToken(@FormParam("grant_type") String grantType, @FormParam("
     @GET
     @Path("/sessions")
     @Operation(operationId = "getSessionsForCurrentUser", summary = "List the sessions associated to the authenticated user.", responses = {
-            @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = UserSessionDTO.class))),
+            @ApiResponse(responseCode = "200", description = "OK", content = @Content(array = @ArraySchema(schema = @Schema(implementation = UserSessionDTO.class)))),
             @ApiResponse(responseCode = "401", description = "User is not authenticated"),
             @ApiResponse(responseCode = "404", description = "User not found") })
     @Produces({ MediaType.APPLICATION_JSON })
@@ -165,8 +166,8 @@ public Response getSessions(@Context SecurityContext securityContext) {
 
     @GET
     @Path("/apitokens")
-    @Operation(operationId = "getApiToken", summary = "List the API tokens associated to the authenticated user.", responses = {
-            @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = UserApiTokenDTO.class))),
+    @Operation(operationId = "getApiTokens", summary = "List the API tokens associated to the authenticated user.", responses = {
+            @ApiResponse(responseCode = "200", description = "OK", content = @Content(array = @ArraySchema(schema = @Schema(implementation = UserApiTokenDTO.class)))),
             @ApiResponse(responseCode = "401", description = "User is not authenticated"),
             @ApiResponse(responseCode = "404", description = "User not found") })
     @Produces({ MediaType.APPLICATION_JSON })
@@ -244,9 +245,8 @@ public Response deleteSession(@Nullable @FormParam("refresh_token") String refre
         ResponseBuilder response = Response.ok();
 
         if (sessionCookie != null && sessionCookie.getValue().equals(session.get().getSessionId())) {
-            URI domainUri;
             try {
-                domainUri = new URI(session.get().getRedirectUri());
+                URI domainUri = new URI(session.get().getRedirectUri());
                 NewCookie newCookie = new NewCookie(SESSIONID_COOKIE_NAME, null, "/", domainUri.getHost(), null, 0,
                         false, true);
                 response.cookie(newCookie);
diff --git a/bundles/org.openhab.core.io.rest.auth/src/main/java/org/openhab/core/io/rest/auth/internal/UserApiTokenDTO.java b/bundles/org.openhab.core.io.rest.auth/src/main/java/org/openhab/core/io/rest/auth/internal/UserApiTokenDTO.java
index cc0d18c467a..e8cfff4e02f 100644
--- a/bundles/org.openhab.core.io.rest.auth/src/main/java/org/openhab/core/io/rest/auth/internal/UserApiTokenDTO.java
+++ b/bundles/org.openhab.core.io.rest.auth/src/main/java/org/openhab/core/io/rest/auth/internal/UserApiTokenDTO.java
@@ -20,9 +20,9 @@
  * @author Yannick Schaus - initial contribution
  */
 public class UserApiTokenDTO {
-    String name;
-    Date createdTime;
-    String scope;
+    public String name;
+    public Date createdTime;
+    public String scope;
 
     public UserApiTokenDTO(String name, Date createdTime, String scope) {
         super();
diff --git a/bundles/org.openhab.core.io.rest.auth/src/main/java/org/openhab/core/io/rest/auth/internal/UserDTO.java b/bundles/org.openhab.core.io.rest.auth/src/main/java/org/openhab/core/io/rest/auth/internal/UserDTO.java
index 289d68946fd..f23623c9046 100644
--- a/bundles/org.openhab.core.io.rest.auth/src/main/java/org/openhab/core/io/rest/auth/internal/UserDTO.java
+++ b/bundles/org.openhab.core.io.rest.auth/src/main/java/org/openhab/core/io/rest/auth/internal/UserDTO.java
@@ -22,8 +22,8 @@
  * @author Yannick Schaus - initial contribution
  */
 public class UserDTO {
-    String name;
-    Collection<String> roles;
+    public String name;
+    public Collection<String> roles;
 
     public UserDTO(User user) {
         super();
diff --git a/bundles/org.openhab.core.io.rest.auth/src/main/java/org/openhab/core/io/rest/auth/internal/UserSessionDTO.java b/bundles/org.openhab.core.io.rest.auth/src/main/java/org/openhab/core/io/rest/auth/internal/UserSessionDTO.java
index 0e71f4e82de..21444def8f6 100644
--- a/bundles/org.openhab.core.io.rest.auth/src/main/java/org/openhab/core/io/rest/auth/internal/UserSessionDTO.java
+++ b/bundles/org.openhab.core.io.rest.auth/src/main/java/org/openhab/core/io/rest/auth/internal/UserSessionDTO.java
@@ -20,11 +20,11 @@
  * @author Yannick Schaus - initial contribution
  */
 public class UserSessionDTO {
-    String sessionId;
-    Date createdTime;
-    Date lastRefreshTime;
-    String clientId;
-    String scope;
+    public String sessionId;
+    public Date createdTime;
+    public Date lastRefreshTime;
+    public String clientId;
+    public String scope;
 
     public UserSessionDTO(String sessionId, Date createdTime, Date lastRefreshTime, String clientId, String scope) {
         super();
diff --git a/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/addons/AddonResource.java b/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/addons/AddonResource.java
index 1178ff764fd..9d4a90bb5b7 100644
--- a/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/addons/AddonResource.java
+++ b/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/addons/AddonResource.java
@@ -65,6 +65,7 @@
 
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
+import io.swagger.v3.oas.annotations.media.ArraySchema;
 import io.swagger.v3.oas.annotations.media.Content;
 import io.swagger.v3.oas.annotations.media.Schema;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
@@ -120,7 +121,7 @@ protected void removeAddonService(AddonService featureService) {
     @GET
     @Produces(MediaType.APPLICATION_JSON)
     @Operation(operationId = "getAddons", summary = "Get all add-ons.", responses = {
-            @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = String.class))) })
+            @ApiResponse(responseCode = "200", description = "OK", content = @Content(array = @ArraySchema(schema = @Schema(implementation = Addon.class)))) })
     public Response getAddon(
             @HeaderParam("Accept-Language") @Parameter(description = "language") @Nullable String language) {
         logger.debug("Received HTTP GET request at '{}'", uriInfo.getPath());
@@ -132,7 +133,7 @@ public Response getAddon(
     @Path("/types")
     @Produces(MediaType.APPLICATION_JSON)
     @Operation(operationId = "getAddonTypes", summary = "Get all add-on types.", responses = {
-            @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = String.class))) })
+            @ApiResponse(responseCode = "200", description = "OK", content = @Content(array = @ArraySchema(schema = @Schema(implementation = AddonType.class)))) })
     public Response getTypes(
             @HeaderParam("Accept-Language") @Parameter(description = "language") @Nullable String language) {
         logger.debug("Received HTTP GET request at '{}'", uriInfo.getPath());
@@ -145,7 +146,7 @@ public Response getTypes(
     @Path("/{addonId: [a-zA-Z_0-9-:]+}")
     @Produces(MediaType.APPLICATION_JSON)
     @Operation(operationId = "getAddonById", summary = "Get add-on with given ID.", responses = {
-            @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = String.class))),
+            @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = Addon.class))),
             @ApiResponse(responseCode = "404", description = "Not found") })
     public Response getById(
             @HeaderParam("Accept-Language") @Parameter(description = "language") @Nullable String language,
diff --git a/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/item/ItemResource.java b/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/item/ItemResource.java
index d31ae8f9baf..739bbb85b5c 100644
--- a/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/item/ItemResource.java
+++ b/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/item/ItemResource.java
@@ -574,7 +574,7 @@ public Response removeMetadata(@PathParam("itemname") @Parameter(description = "
     @Consumes(MediaType.APPLICATION_JSON)
     @Operation(operationId = "addOrUpdateItemInRegistry", summary = "Adds a new item to the registry or updates the existing item.", security = {
             @SecurityRequirement(name = "oauth2", scopes = { "admin" }) }, responses = {
-                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = String.class))),
+                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = EnrichedItemDTO.class))),
                     @ApiResponse(responseCode = "201", description = "Item created."),
                     @ApiResponse(responseCode = "400", description = "Payload invalid."),
                     @ApiResponse(responseCode = "404", description = "Item not found or name in path invalid."),
diff --git a/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/link/ItemChannelLinkResource.java b/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/link/ItemChannelLinkResource.java
index 0401e60d7fb..e59061046d8 100644
--- a/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/link/ItemChannelLinkResource.java
+++ b/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/link/ItemChannelLinkResource.java
@@ -114,7 +114,7 @@ public Response getAll(
     @GET
     @Path("/{itemName}/{channelUID}")
     @Operation(operationId = "getItemLink", summary = "Retrieves an individual link.", responses = {
-            @ApiResponse(responseCode = "200", description = "OK"),
+            @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = ItemChannelLinkDTO.class))),
             @ApiResponse(responseCode = "404", description = "Content does not match the path") })
     public Response getLink(@PathParam("itemName") @Parameter(description = "itemName") String itemName,
             @PathParam("channelUID") @Parameter(description = "channelUID") String channelUid) {
diff --git a/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/persistence/PersistenceResource.java b/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/persistence/PersistenceResource.java
index cb2da517d1e..21ae1196745 100644
--- a/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/persistence/PersistenceResource.java
+++ b/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/persistence/PersistenceResource.java
@@ -53,6 +53,7 @@
 import org.openhab.core.persistence.FilterCriteria.Ordering;
 import org.openhab.core.persistence.HistoricItem;
 import org.openhab.core.persistence.ModifiablePersistenceService;
+import org.openhab.core.persistence.PersistenceItemInfo;
 import org.openhab.core.persistence.PersistenceService;
 import org.openhab.core.persistence.PersistenceServiceRegistry;
 import org.openhab.core.persistence.QueryablePersistenceService;
@@ -133,7 +134,7 @@ public PersistenceResource( //
     @Produces({ MediaType.APPLICATION_JSON })
     @Operation(operationId = "getPersistenceServices", summary = "Gets a list of persistence services.", security = {
             @SecurityRequirement(name = "oauth2", scopes = { "admin" }) }, responses = {
-                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(array = @ArraySchema(schema = @Schema(implementation = String.class)))) })
+                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(array = @ArraySchema(schema = @Schema(implementation = PersistenceServiceDTO.class)))) })
     public Response httpGetPersistenceServices(@Context HttpHeaders headers,
             @HeaderParam(HttpHeaders.ACCEPT_LANGUAGE) @Parameter(description = "language") @Nullable String language) {
         Locale locale = localeService.getLocale(language);
@@ -148,7 +149,7 @@ public Response httpGetPersistenceServices(@Context HttpHeaders headers,
     @Produces({ MediaType.APPLICATION_JSON })
     @Operation(operationId = "getItemsForPersistenceService", summary = "Gets a list of items available via a specific persistence service.", security = {
             @SecurityRequirement(name = "oauth2", scopes = { "admin" }) }, responses = {
-                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(array = @ArraySchema(schema = @Schema(implementation = String.class)))) })
+                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(array = @ArraySchema(schema = @Schema(implementation = PersistenceItemInfo.class), uniqueItems = true))) })
     public Response httpGetPersistenceServiceItems(@Context HttpHeaders headers,
             @Parameter(description = "Id of the persistence service. If not provided the default service will be used") @QueryParam("serviceId") @Nullable String serviceId) {
         return getServiceItemList(serviceId);
@@ -199,7 +200,7 @@ public Response httpDeletePersistenceServiceItem(@Context HttpHeaders headers,
     @Path("/items/{itemname: [a-zA-Z_0-9]+}")
     @Produces({ MediaType.APPLICATION_JSON })
     @Operation(operationId = "storeItemDataInPersistenceService", summary = "Stores item persistence data into the persistence service.", responses = {
-            @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = ItemHistoryDTO.class))),
+            @ApiResponse(responseCode = "200", description = "OK"),
             @ApiResponse(responseCode = "404", description = "Unknown Item or persistence service") })
     public Response httpPutPersistenceItemData(@Context HttpHeaders headers,
             @Parameter(description = "Id of the persistence service. If not provided the default service will be used") @QueryParam("serviceId") @Nullable String serviceId,
diff --git a/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/service/ConfigurableServiceResource.java b/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/service/ConfigurableServiceResource.java
index bf0b0998a7c..2172d16078a 100644
--- a/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/service/ConfigurableServiceResource.java
+++ b/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/service/ConfigurableServiceResource.java
@@ -121,8 +121,7 @@ public ConfigurableServiceResource( //
     @Operation(operationId = "getServices", summary = "Get all configurable services.", responses = {
             @ApiResponse(responseCode = "200", description = "OK", content = @Content(array = @ArraySchema(schema = @Schema(implementation = ConfigurableServiceDTO.class)))) })
     public List<ConfigurableServiceDTO> getAll() {
-        List<ConfigurableServiceDTO> services = getConfigurableServices();
-        return services;
+        return getConfigurableServices();
     }
 
     @GET
@@ -172,8 +171,7 @@ public Response getById(@PathParam("serviceId") @Parameter(description = "servic
             @ApiResponse(responseCode = "200", description = "OK", content = @Content(array = @ArraySchema(schema = @Schema(implementation = ConfigurableServiceDTO.class)))) })
     public List<ConfigurableServiceDTO> getMultiConfigServicesByFactoryPid(
             @PathParam("serviceId") @Parameter(description = "service ID") String serviceId) {
-        List<ConfigurableServiceDTO> services = collectServicesById(serviceId);
-        return services;
+        return collectServicesById(serviceId);
     }
 
     private List<ConfigurableServiceDTO> collectServicesById(String serviceId) {
diff --git a/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/thing/ThingResource.java b/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/thing/ThingResource.java
index 5306b4314a2..d594ff0b5bc 100644
--- a/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/thing/ThingResource.java
+++ b/bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/thing/ThingResource.java
@@ -54,6 +54,7 @@
 import org.openhab.core.config.core.ConfigUtil;
 import org.openhab.core.config.core.Configuration;
 import org.openhab.core.config.core.status.ConfigStatusInfo;
+import org.openhab.core.config.core.status.ConfigStatusMessage;
 import org.openhab.core.config.core.status.ConfigStatusService;
 import org.openhab.core.config.core.validation.ConfigValidationException;
 import org.openhab.core.io.rest.DTOMapper;
@@ -217,7 +218,7 @@ public ThingResource( //
     @Consumes(MediaType.APPLICATION_JSON)
     @Operation(operationId = "createThingInRegistry", summary = "Creates a new thing and adds it to the registry.", security = {
             @SecurityRequirement(name = "oauth2", scopes = { "admin" }) }, responses = {
-                    @ApiResponse(responseCode = "201", description = "Created", content = @Content(schema = @Schema(implementation = String.class))),
+                    @ApiResponse(responseCode = "201", description = "Created", content = @Content(schema = @Schema(implementation = EnrichedThingDTO.class))),
                     @ApiResponse(responseCode = "400", description = "Thing uid does not match bridge uid."),
                     @ApiResponse(responseCode = "400", description = "A uid must be provided, if no binding can create a thing of this type."),
                     @ApiResponse(responseCode = "409", description = "A thing with the same uid already exists.") })
@@ -316,7 +317,7 @@ public Response getAll(
     @Produces(MediaType.APPLICATION_JSON)
     @Operation(operationId = "getThingById", summary = "Gets thing by UID.", security = {
             @SecurityRequirement(name = "oauth2", scopes = { "admin" }) }, responses = {
-                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = ThingDTO.class))),
+                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = EnrichedThingDTO.class))),
                     @ApiResponse(responseCode = "404", description = "Thing not found.") })
     public Response getByUID(
             @HeaderParam(HttpHeaders.ACCEPT_LANGUAGE) @Parameter(description = "language") @Nullable String language,
@@ -406,7 +407,7 @@ public Response remove(
     @Consumes(MediaType.APPLICATION_JSON)
     @Operation(operationId = "updateThing", summary = "Updates a thing.", security = {
             @SecurityRequirement(name = "oauth2", scopes = { "admin" }) }, responses = {
-                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = ThingDTO.class))),
+                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = EnrichedThingDTO.class))),
                     @ApiResponse(responseCode = "404", description = "Thing not found."),
                     @ApiResponse(responseCode = "409", description = "Thing could not be updated as it is not editable.") })
     public Response update(
@@ -466,7 +467,7 @@ public Response update(
     @Consumes(MediaType.APPLICATION_JSON)
     @Operation(operationId = "updateThingConfig", summary = "Updates thing's configuration.", security = {
             @SecurityRequirement(name = "oauth2", scopes = { "admin" }) }, responses = {
-                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = ThingDTO.class))),
+                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = EnrichedThingDTO.class))),
                     @ApiResponse(responseCode = "400", description = "Configuration of the thing is not valid."),
                     @ApiResponse(responseCode = "404", description = "Thing not found"),
                     @ApiResponse(responseCode = "409", description = "Thing could not be updated as it is not editable.") })
@@ -523,7 +524,7 @@ public Response updateConfiguration(
     @Produces(MediaType.APPLICATION_JSON)
     @Operation(operationId = "getThingStatus", summary = "Gets thing status.", security = {
             @SecurityRequirement(name = "oauth2", scopes = { "admin" }) }, responses = {
-                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = String.class))),
+                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = ThingStatusInfo.class))),
                     @ApiResponse(responseCode = "404", description = "Thing not found.") })
     public Response getStatus(
             @HeaderParam(HttpHeaders.ACCEPT_LANGUAGE) @Parameter(description = "language") @Nullable String language,
@@ -548,7 +549,7 @@ public Response getStatus(
     @Path("/{thingUID}/enable")
     @Operation(operationId = "enableThing", summary = "Sets the thing enabled status.", security = {
             @SecurityRequirement(name = "oauth2", scopes = { "admin" }) }, responses = {
-                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = String.class))),
+                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = EnrichedThingDTO.class))),
                     @ApiResponse(responseCode = "404", description = "Thing not found.") })
     public Response setEnabled(
             @HeaderParam(HttpHeaders.ACCEPT_LANGUAGE) @Parameter(description = "language") @Nullable String language,
@@ -578,7 +579,7 @@ public Response setEnabled(
     @Produces(MediaType.APPLICATION_JSON)
     @Operation(operationId = "getThingConfigStatus", summary = "Gets thing config status.", security = {
             @SecurityRequirement(name = "oauth2", scopes = { "admin" }) }, responses = {
-                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = String.class))),
+                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(array = @ArraySchema(schema = @Schema(implementation = ConfigStatusMessage.class)))),
                     @ApiResponse(responseCode = "404", description = "Thing not found.") })
     public Response getConfigStatus(
             @HeaderParam(HttpHeaders.ACCEPT_LANGUAGE) @Parameter(description = "language") String language,
@@ -643,7 +644,7 @@ public Response updateFirmware(
     @Path("/{thingUID}/firmware/status")
     @Operation(operationId = "getThingFirmwareStatus", summary = "Gets thing's firmware status.", security = {
             @SecurityRequirement(name = "oauth2", scopes = { "admin" }) }, responses = {
-                    @ApiResponse(responseCode = "200", description = "OK"),
+                    @ApiResponse(responseCode = "200", description = "OK", content = @Content(schema = @Schema(implementation = FirmwareStatusDTO.class))),
                     @ApiResponse(responseCode = "204", description = "No firmware status provided by this Thing.") })
     public Response getFirmwareStatus(
             @HeaderParam(HttpHeaders.ACCEPT_LANGUAGE) @Parameter(description = "language") @Nullable String language,
diff --git a/bundles/org.openhab.core.io.rest.sitemap/src/main/java/org/openhab/core/io/rest/sitemap/internal/SitemapResource.java b/bundles/org.openhab.core.io.rest.sitemap/src/main/java/org/openhab/core/io/rest/sitemap/internal/SitemapResource.java
index 01f9450ead5..0d18ffd787c 100644
--- a/bundles/org.openhab.core.io.rest.sitemap/src/main/java/org/openhab/core/io/rest/sitemap/internal/SitemapResource.java
+++ b/bundles/org.openhab.core.io.rest.sitemap/src/main/java/org/openhab/core/io/rest/sitemap/internal/SitemapResource.java
@@ -226,7 +226,7 @@ public void removeSitemapProvider(SitemapProvider provider) {
             @ApiResponse(responseCode = "200", description = "OK", content = @Content(array = @ArraySchema(schema = @Schema(implementation = SitemapDTO.class)))) })
     public Response getSitemaps() {
         logger.debug("Received HTTP GET request from IP {} at '{}'", request.getRemoteAddr(), uriInfo.getPath());
-        Object responseObject = getSitemapBeans(uriInfo.getAbsolutePathBuilder().build());
+        Collection<SitemapDTO> responseObject = getSitemapBeans(uriInfo.getAbsolutePathBuilder().build());
         return Response.ok(responseObject).build();
     }
 
@@ -243,7 +243,7 @@ public Response getSitemapData(@Context HttpHeaders headers,
         final Locale locale = localeService.getLocale(language);
         logger.debug("Received HTTP GET request from IP {} at '{}' for media type '{}'.", request.getRemoteAddr(),
                 uriInfo.getPath(), type);
-        Object responseObject = getSitemapBean(sitemapname, uriInfo.getBaseUriBuilder().build(), locale,
+        SitemapDTO responseObject = getSitemapBean(sitemapname, uriInfo.getBaseUriBuilder().build(), locale,
                 includeHiddenWidgets);
         return Response.ok(responseObject).build();
     }
diff --git a/bundles/org.openhab.core.ui.icon/src/main/java/org/openhab/core/ui/icon/internal/IconSetResource.java b/bundles/org.openhab.core.ui.icon/src/main/java/org/openhab/core/ui/icon/internal/IconSetResource.java
index 3e5e3e892f6..f9c7b8a6990 100644
--- a/bundles/org.openhab.core.ui.icon/src/main/java/org/openhab/core/ui/icon/internal/IconSetResource.java
+++ b/bundles/org.openhab.core.ui.icon/src/main/java/org/openhab/core/ui/icon/internal/IconSetResource.java
@@ -43,6 +43,9 @@
 
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
+import io.swagger.v3.oas.annotations.media.ArraySchema;
+import io.swagger.v3.oas.annotations.media.Content;
+import io.swagger.v3.oas.annotations.media.Schema;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import io.swagger.v3.oas.annotations.tags.Tag;
 
@@ -87,7 +90,7 @@ protected void removeIconProvider(IconProvider iconProvider) {
     @GET
     @Produces(MediaType.APPLICATION_JSON)
     @Operation(operationId = "getIconSets", summary = "Gets all icon sets.", responses = {
-            @ApiResponse(responseCode = "200", description = "OK") })
+            @ApiResponse(responseCode = "200", description = "OK", content = @Content(array = @ArraySchema(schema = @Schema(implementation = IconSet.class)))) })
     public Response getAll(
             @HeaderParam("Accept-Language") @Parameter(description = "language") @Nullable String language) {
         Locale locale = localeService.getLocale(language);