A customer can be created using the /customer/{customer_id}/create endpoint on CustomerEntity:

curl localhost:8080/customer/abc123/create \
  --header "Content-Type: application/json" \
  -XPOST \
  --data '{
    "email": "someone@example.com",
    "name": "Someone",
    "address": {
      "street": "123 Some Street",
      "city": "Somewhere"
    }
  }'

The /customer/abc123 endpoint can be used to retrieve this customer:

curl localhost:8080/customer/abc123