Customer is using below REST API to create project:

curl -X POST -u 'bpmsAdmin:admin12@' -H 'Content-type: application/json' 'http://localhost:8080/business-central/rest/spaces/MySpace/projects' --data '{"name": "SampleProject", "groupId": "com.sample", "version": "1.0.0-SNAPSHOT", "description": "SampleProject"}'

If project with same name already available in space then '-1' is appended to project name. There is no way we can identify it from response.  Ideally, REST API should throw exception if project with same name is available or it should include project name in the response of above REST API.