Devil's in the details - Idioms by The Free Dictionary
the devil is in the detail (redirected from devil's in the details)
the devil is in the detail(s)
Plans, actions, or situations that seem sound must be carefully examined, because minor details can end up causing major, unforeseen problems. Double check your code—with software, the devil is in the details.
the ˌdevil is in the ˈdetail(s) used to say that it is the small individual parts of a task, a written document, a design, etc. that may cause most problems and difficulties: In any negotiation, the devil is in the detail.
References in periodicals archive
Let's just say that the devil's in the details
and screenwriters Erik Jendresen and Jeremy Leven (adapting Leven's 1982 novel, ``Satan: His Psychotherapy and Cure by the Unfortunate Dr.