JIRA API and CORS Troubleshooting

Other Questions Jira
1

Using JavaScript fetch to access the JIRA API triggers CORS errors while direct URL, Postman, and curl calls work. Sample code:

const configOptions = {
  method: 'GET',
  headers: {
    'Content-Type': 'application/json',
    'Auth': 'Basic newEncodedValue'
  }
};
fetch('https://jira-example.com/api/issues', configOptions);

Any ideas?

2

Based on my previous experience with JIRA APIs, the problem is almost certainly coming from the server not including the required CORS headers in its response. When I encountered similar issues, none of the changes on the client side were able to overcome the browser-enforcement of CORS policies. I ended up setting up a small server-side proxy that made the requests to the API and then served the results to the client with the appropriate headers. Additionally, reviewing the authentication method used in the headers helped ensure no conflict that might trigger the CORS errors.

3

In my experience, the issue stems from the fact that browsers enforce CORS, and server responses without the necessary headers will always be blocked even if tools like curl or Postman work perfectly. I had a similar problem once where adjusting client-side headers didn’t help because the server wasn’t configured to allow cross-origin requests. After verifying that the JIRA instance supports preflight and proper CORS headers, I switched to a setup using a device-proxy which relays requests and injects the required CORS headers. This approach ultimately resolved the browser error while maintaining API security.

4

hey, i’ve been in the same boat. mine turned out to be a server side config problem. even with proper headers in fetch, if jira doesn’t allow the origin, it fails. figured a local proxy solved it for me. hope it gives you a lead!

5

My experience with similar issues led me to reexamine both the client and server setups. I discovered that even a minor misconfiguration on the server can result in missing or incorrect CORS headers. In my case, after confirming that my fetch request was properly formed, I worked with our backend team to adjust the middleware settings so that the API correctly handled preflight requests and returned the necessary Access-Control-Allow-Origin header. Simultaneously, I verified that our encoded authentication token was correctly applied, which helped eliminate any additional interference with CORS behavior.