There shouldn't be more than one active case open at once for a single contact. user should be able to raise another case when there is no active case.
Could anyone help me with this using plugin.

There shouldn't be more than one active case open at once for a single contact. user should be able to raise another case when there is no active case.
Could anyone help me with this using plugin.
Hi Tanvi,
There is no need to create one plugin, you can create one rollup field and workflow to achieve it.
1.Creating rollup field to count related active case in the contact:
2.Then create one real-time workflow:
--check the rollup field value when creating new cases.
Save and active it.
Test:
Creating one new case related to the 02 contact: