How to prevent duplicate records insertion with salesforce and jira two way integration

Hi Mates,

I have a requirement of two way integration of salesforce and jira through REST API,
when case is created/edited/deleted in salesforce and issue is created/edited/deleted in jira vice versa..

for this i did below code for first creation part

from sf to jira
created webservice callout to push records from salesforce to jira with trigger and prevented recusrtion with static varibale

from jira to sf
created webhook to call salesforce public class to insert record from jira to sf

now i can able to push records from sf to jira and jira to sf, But duplicate records inserting in sf and jira

How to prevent this , can any one help me on this..