Kiva does that [https://www.kiva.org].

Kiva is a lending platform focused on micro-finance. All the money you lend directly goes to the borrowers(via its lending partners), and once the lender returns the money, you can recycle the amount to another borrower on the website.

They do have suggested donations to Kiva, usually 10%/15%/20%/self-specify of the loan amount.