Sigil - City of Doors (SCoD) has largely unrestricted rest. No alterations to in the manner of gaining health, spells nor any requirements for consumption of food or substances to be able to rest.
There however will be some areas and dungeons where resting is impossible. In these areas you may be required to spend consumable items such as potions or scrolls to survive and to think ahead while using your spells and talents in moderation as not to run out too soon.
Exception: During Events
During events players should ask first from the Dungeon Master (DM) or Event Master (EM) handling the event if it is alright to rest. Sometimes a DM or EM will wish to restrict it.