How to add issues using Backlog API

Hi @rvpandya93

I checked with our Backlog Tech Support team, the issue is you’re trying to post parameters in JSON.

But as written in the API reference, parameters should be posted in the context of form parameters.

I think perhaps can you try similar to this format?
from https://reqbin.com/req/c-sma2qrvp/curl-post-form-example

curl -X POST https://[spaceid].backlog.com/api/v2/issues?apiKey=[yourAPIkey]
   -H "Content-Type: application/x-www-form-urlencoded" 
   -d "param1=value1&param2=value2" 

Thus, adding issue with custom field:

curl -X POST https://[spaceid].backlog.com/api/v2/issues?apiKey=[yourAPIkey]
   -H 'Content-Type:application/x-www-form-urlencoded'
   -d 'projectId=58693&summary=”This is the title/subject of the issue"&issueTypeId=248839&priorityId=3&customField_6680=[yourvalue]'

Another syntax:

curl https://[spaceid].backlog.com/api/v2/issues?apiKey=[yourAPIkey]
   -d 'projectId=58693&summary=”This is the title/subject of the issue"&issueTypeId=248839&priorityId=3&customField_6680=[yourvalue]'

My earlier example of using JSON for adding issue works only for adding issues without custom fields, but the correct format should be using form parameters. So I’ve corrected it above.