categories: Affordability, Customer Service, Rate Transparency, Loan Options, and Additional Benefits. Lenders are rated on a scale of 1 to 5 stars, with 5 being the highest score. The final score is an average of the scores in each category. Yahoo Finance also considers factors such as interest rates, loan costs, customer reviews, and overall reputation when determining the best online mortgage lenders. It is important for borrowers to compare multiple lenders and consider their individual needs and preferences before choosing a mortgage lender.