I like SaveBetter, but their process for maturing CD's is different and could lead to a renewal that you did not want.
Most banks that I have dealt with have a grace period of 7-14 days after the maturity date where you can close or renew the CD.
SaveBetter (as I understand it) will renew your CD on the maturity date so if you are expecting a grace period you might be out of luck (e.g., have to pay a Early Withdrawal penalty if you don't want the renewal).
There is an option on a SaveBetter CD to specify on maturity date to either 1) renew the CD for the same length or 2) transfer funds to your linked bank account). THE DEFAULT is option 1 (renew). You can change that to option 2 (transfer funds out). I have done this on my CD's.