I am currently looking at working as a Backend Developer for ClearScore (https://www.clearscore.com/) and was wondering if it is permissible for me to work there?
I think that, if you are involved in offering interest based credit offers, then it would be problematic from a shariah perspective.
I would need more information on what is it you are doing in terms of working towards the improvement of the credit score.
Nevertheless, given the first point and also the fact that these companies are receiving a commission for every interest based product they sell, I believe it is not correct to work in this role.
However, given the current economic climate, if you are in need of an income to afford the basic necessities of life, then take the job until you can find something more suitable inshaAllah.