While it may be technically possible to use it for a DEV environment (we don't use it), it is not usable for a PROD or TEST System.
These are the licensing terms for Express Edition:
Oracle Express Edition
Oracle XE is a free version of Oracle that is limited to 1 processor, 1 GB RAM and 4 GB of data. It is also limited to 1 database on a computer, since the database must be named XE which must be unique.
Oracle Standard Edition One is the cheapest route
Rgds
Gary