How to get a faster Pre-approval Letter from lenders?

[Kal Wol]

Hello awesome BPs

I am trying to have a pre-approval letter prepared as quick as possible as it is a requirement for the offer, that is what I have been told. Looking around redfin have lending product and they can make it faster on such cases, anyone who have used them in the past and how was it?

With the big banks, I think it might take a bit longer time and I am wondering if there is any other way to put the offer. I have suggested a bit higher Earnest money but I doubt if the seller would like that idea. I should not have any problem getting the letter, it is just I wanted it faster.

Thank you all.