Rails core validations Client-side validates_acceptance_of – except: :on, :if/:unless validates_confirmation_of – except: :on, :if/:unless validates_exclusion_of – except: :on, :if/:unless validates_format_of – except: :on, :if/:unless validates_inclusion_of – except: :on, :if/:unless validates_length_of – except: :on, :if/:unless validates_numericality_of – except: :on, :if/:unless validates_pres