Not able to create issue with customfields

I’m facing a problem, when I’m trying to create an issue through JIRA API.
I have to send some customfields, but whenever I send values, I receive errors.

“customfield_10324”:[“test1”]
If I send it like this, I get ‘expected Object’ back.

“customfield_10324”:[{“value”:“test1”}]
If I send it like this, I get fields are required back, so basically it doesn’t recognize as the intended customfield.

“customfield_10324”:{“value”:“test1”}
If I send it like this, I get ‘data was not an array’ back.

Can you help me out here?