Yes, you can link joint bank accounts to Cheddar. However, only one account holder can link the joint account to their Cheddar profile.
For instance, if Mr. and Mrs. Smith have a joint account, only Mr. Smith or Mrs. Smith can link it to their respective Cheddar profile.
Note: in this scenario, any purchases made by Mrs. Smith with her individual card, (which is still linked to the joint account) will earn cashback but only at the rate applicable to Mr. Smith’s profile.