diff --git a/code/API_definitions/kyc-match.yaml b/code/API_definitions/kyc-match.yaml
index 26474e5..2d654fc 100644
--- a/code/API_definitions/kyc-match.yaml
+++ b/code/API_definitions/kyc-match.yaml
@@ -213,7 +213,8 @@ components:
         phoneNumber:
           type: string
           description: A public identifier addressing a telephone subscription. In mobile networks it corresponds to the MSISDN (Mobile Station International Subscriber Directory Number). In order to be globally unique it has to be formatted in international format, according to E.164 standard, prefixed with '+'.
-
+          pattern: '^\+[1-9][0-9]{4,14}$'
+          example: "+123456789"
 
         idDocument:
           type: string