diff --git a/plug-api/lib/query.ts b/plug-api/lib/query.ts
index a1613295..33a13455 100644
--- a/plug-api/lib/query.ts
+++ b/plug-api/lib/query.ts
@@ -25,6 +25,9 @@ export function evalQueryExpression(
     // Value types
     case "null":
       return null;
+    // TODO: Add this to the actualy query syntax
+    case "not":
+      return !evalQueryExpression(op1, obj, functionMap);
     case "number":
     case "string":
     case "boolean":
diff --git a/plug-api/types.ts b/plug-api/types.ts
index 2b2d439d..496c9f52 100644
--- a/plug-api/types.ts
+++ b/plug-api/types.ts
@@ -97,6 +97,7 @@ export type QueryExpression =
   | ["string", string]
   | ["boolean", boolean]
   | ["null"]
+  | ["not", QueryExpression]
   | ["array", QueryExpression[]]
   | ["object", Record<string, any>]
   | ["regexp", string, string] // regex, modifier
@@ -145,4 +146,4 @@ export type UploadFile = {
   name: string;
   contentType: string;
   content: Uint8Array;
-}
\ No newline at end of file
+};