wow...so is this going to stay up or be C&Ded... any bets...
It's using the basic rules only so should be fine.
Have the basic rules been released as OGL? If not, just because something is distributed freely, doesn't mean it suddenly becomes exempt from Copyright protection.
There is no safety net of the OGL, but previous 5e character generators were hit with C&Ds until they removed all non-Basic Rules material, after which they were okay.