diff --git a/src/main/java/de/ids_mannheim/korap/KrillCollection.java b/src/main/java/de/ids_mannheim/korap/KrillCollection.java
index 38b0a48..58761d7 100644
--- a/src/main/java/de/ids_mannheim/korap/KrillCollection.java
+++ b/src/main/java/de/ids_mannheim/korap/KrillCollection.java
@@ -1,12 +1,11 @@
 package de.ids_mannheim.korap;
 
-import java.util.*;
 import java.io.IOException;
 
 import de.ids_mannheim.korap.collection.CollectionBuilder;
 import de.ids_mannheim.korap.response.Notifications;
 import de.ids_mannheim.korap.util.QueryException;
-import de.ids_mannheim.korap.response.Result;
+import de.ids_mannheim.korap.util.StatusCode;
 
 import org.apache.lucene.search.*;
 import org.apache.lucene.index.*;
@@ -86,13 +85,20 @@
         ObjectMapper mapper = new ObjectMapper();
         try {
             JsonNode json = mapper.readTree(jsonString);
-
-            if (json.has("collection"))
+ 
+            if (json.has("errors") & json.get("errors").size()>0){
+                this.addError(StatusCode.INVALID_QUERY,"Json has errors.");
+            }
+            else if (json.has("collection")){
                 this.fromKoral(json.get("collection"));
-
-            else if (json.has("collections"))
+            }
+            else if (json.has("collections")){
                 this.addError(899,
                         "Collections are not supported anymore in favour of a single collection");
+            }
+            else{
+                this.addError(StatusCode.MISSING_COLLECTION, "Collection is not found.");
+            }
         }
 
         // Query Exception
diff --git a/src/main/java/de/ids_mannheim/korap/response/Notifications.java b/src/main/java/de/ids_mannheim/korap/response/Notifications.java
index bc4091d..274ca09 100644
--- a/src/main/java/de/ids_mannheim/korap/response/Notifications.java
+++ b/src/main/java/de/ids_mannheim/korap/response/Notifications.java
@@ -13,6 +13,7 @@
 import de.ids_mannheim.korap.response.Message;
 import de.ids_mannheim.korap.response.Messages;
 import de.ids_mannheim.korap.util.QueryException;
+import de.ids_mannheim.korap.util.StatusCode;
 
 /**
  * A unified notification class for KorAP related errors,
@@ -237,6 +238,13 @@
         this.errors.add(code, msg, terms);
         return this;
     };
+    
+    public Notifications addError (StatusCode status, String msg, String ... terms) {
+        if (this.errors == null)
+            this.errors = new Messages();
+        this.errors.add(status.getCode(), msg, terms);
+        return this;
+    };
 
 
     /**
diff --git a/src/main/java/de/ids_mannheim/korap/util/StatusCode.java b/src/main/java/de/ids_mannheim/korap/util/StatusCode.java
new file mode 100644
index 0000000..fda3a86
--- /dev/null
+++ b/src/main/java/de/ids_mannheim/korap/util/StatusCode.java
@@ -0,0 +1,90 @@
+package de.ids_mannheim.korap.util;
+
+public enum StatusCode {
+    // 600 - 699 - Krill server error codes
+    UNABLE_TO_READ_INDEX(600), 
+    UNABLE_TO_FIND_INDEX(601),
+    UNABLE_TO_ADD_DOC_TO_INDEX(602),
+    UNABLE_TP_COMMIT_STAGED_DATA_TO_INDEX(603),
+    UNABLE_TO_CONNECT_TO_DB(604),
+    MISSING_REQUEST_PARAMETER(610),
+    ARBITRARY_DESERIALIZATION_ERROR(613),
+    UNABLE_TO_GENERATE_JSON(620),
+    UNABLE_TO_PARSE_JSON(621),
+    DOCUMENT_NOT_FOUND(630),
+    UNABLE_TO_EXTEND_CONTEXT(651),
+    SERVER_IS_RUNNING(680),
+    DOC_ADDED(681),
+    RESPONSE_TIME_EXCEEDED(682),
+    STAGED_DATA_COMMITTED(683),
+    
+//    700 - 799 - KoralQuery Deserialization errors
+    NO_QUERY_GIVEN(700),
+    MISSING_TYPE(701),
+    INVALID_BOUNDARY(702),
+    MISSING_OPERATION(703),
+    MISSING_OPERAND_LIST(704),
+    NUMBER_OF_OPERAND_NOT_ACCEPTABLE(705),
+    UNKNOWN_FRAME_TYPE(706),
+    INVALID_DISTANCE_CONSTRAINTS(707),
+    MISSING_DISTANCE(708),
+    VALID_CLASS_NUMBER_EXCEEDED(709),
+    MISSING_CLASS_ATTRIBUTE(710),
+    UNKNOWN_GROUP_OPERATION(711),
+    UNKNOWN_REFERENCE_OPERATION(712),
+    UNSUPPORTED_QUERY(713),
+    INVALID_SPAN_REFERENCE_PARAMETER(714),
+    UNSUPPORTED_ATTRIBUTE_TYPE(715),
+    UNKNOWN_RELATION(716),
+    MISSING_RELATION_NODE(717),
+    MISSING_RELATION_TERM(718),
+    INVALID_QUERY(719),
+    INVALID_MATCH_ID(730),
+    MISSING_KEY(740),
+    UNKNOWN_MATCH_RELATION(741),
+    MISSING_TERM_RELATION(743),
+    UNSUPPORTED_OPERAND(744),
+    UNSUPPORTED_TOKEN_TYPE(745),
+    UNSUPPORTED_TERM_TYPE(746),
+    NULL_ATTRIBUTE(747),
+    UNKNOWN_FLAG(748),
+    NON_WELL_FORMED_NOTIFICATION(750),
+    UNSUPPORTED_OPERATION(760),
+    UNSUPPORTED_OPERATOR(761),
+    QUERY_MATCH_EVERYWHERE(780),
+    IGNORE_OPTIONALITY(781),
+    IGNORE_EXCLUSIVITY(782),
+    QUERY_CANNOT_MATCH_ANYWHERE(783),
+    UNKNOWN_QUERY_SERIALIZATION_MESSAGE(799),
+
+//    800 - 899 - Virtual Collection Messages
+    MISSING_COLLECTION(800),
+    UNSUPPORTED_MATCH_TYPE(802),
+    UNKNOWN_VALUE_TYPE(804),
+    INVALID_VALUE(805),
+    INVALID_DATE_STRING(806),
+    INVALID_REGEX(807),
+    UNKNOWN_REWRITE_OPERATION(814),
+    MISSING_SOURCE(815),
+    MISSING_VALUE(820),
+    EMPTY_FILTER(830),
+    UNWRAPPABLE_FILTER(831),
+    INVALID_FILTER_OPERATION(832),
+    UNSUPPORTED_TYPE(843),
+    COLLECTIONS_UNSUPPORTED(850),
+    
+    
+//    900 - 999 - Corpus Data errors 
+    INVALID_OFFSET(952),
+    INCOMPLETE_OFFSET(953),
+    INVALID_FOUNDRY(970);
+
+    private int code;
+    StatusCode (int code) {
+        this.code = code;
+    }
+   
+    public int getCode () {
+        return code;
+    }
+}