diff --git a/app/src/main/java/ru/dragonestia/picker/controller/NodeController.java b/app/src/main/java/ru/dragonestia/picker/controller/NodeController.java
index 9c45ade..fa3a4df 100644
--- a/app/src/main/java/ru/dragonestia/picker/controller/NodeController.java
+++ b/app/src/main/java/ru/dragonestia/picker/controller/NodeController.java
@@ -8,16 +8,23 @@ import ru.dragonestia.picker.controller.response.NodeDetailsResponse;
 import ru.dragonestia.picker.controller.response.NodeListResponse;
 import ru.dragonestia.picker.controller.response.NodeRegisterResponse;
 import ru.dragonestia.picker.model.Node;
+import ru.dragonestia.picker.model.Room;
+import ru.dragonestia.picker.model.User;
 import ru.dragonestia.picker.model.type.PickingMode;
 import ru.dragonestia.picker.service.NodeService;
+import ru.dragonestia.picker.service.RoomService;
 import ru.dragonestia.picker.util.NamingValidator;
 
+import java.util.LinkedList;
+import java.util.Optional;
+
 @RestController
 @RequestMapping("/nodes")
 @RequiredArgsConstructor
 public class NodeController {
 
     private final NodeService nodeService;
+    private final RoomService roomService;
 
     @GetMapping
     NodeListResponse allNodes() {
@@ -61,4 +68,36 @@ public class NodeController {
 
         return ResponseEntity.ok().build();
     }
+
+    @PostMapping("/{nodeId}/pick")
+    ResponseEntity<?> pickRoom(@PathVariable("nodeId") String nodeId,
+                               @RequestParam(name = "userIds") String userIds) {
+
+        if (!NamingValidator.validateNodeId(nodeId)) {
+            return new ResponseEntity<>(HttpStatusCode.valueOf(404));
+        }
+
+        var nodeOpt = nodeService.find(nodeId);
+        if (nodeOpt.isEmpty()) {
+            return new ResponseEntity<>(HttpStatusCode.valueOf(404));
+        }
+
+        var node = nodeOpt.get();
+
+        var list = new LinkedList<User>();
+        for (var username: userIds.split(",")) { // TODO: create warnings about invalid usernames
+            if (!NamingValidator.validateUserId(username)) continue;
+
+            list.add(new User(username));
+        }
+
+        Room room;
+        try {
+            room = roomService.pickAvailable(node, list);
+        } catch (RuntimeException ex) {
+            return new ResponseEntity<>(HttpStatusCode.valueOf(409));
+        }
+
+        return ResponseEntity.ok(room); // TODO: make other json schema
+    }
 }
diff --git a/app/src/main/java/ru/dragonestia/picker/service/impl/RoomServiceImpl.java b/app/src/main/java/ru/dragonestia/picker/service/impl/RoomServiceImpl.java
index e5fb7ea..76cbe50 100644
--- a/app/src/main/java/ru/dragonestia/picker/service/impl/RoomServiceImpl.java
+++ b/app/src/main/java/ru/dragonestia/picker/service/impl/RoomServiceImpl.java
@@ -49,6 +49,7 @@ public class RoomServiceImpl implements RoomService {
 
     @Override
     public Room pickAvailable(Node node, List<User> users) {
-        throw new RuntimeException("Not implemented");
+        return roomRepository.pickFree(node, users)
+                .orElseThrow(() -> new RuntimeException("There are no rooms available"));
     }
 }