Financial technology has reshaped commercial banking. It has the potential to radically alter the transmission of monetary policy by lowering search costs and expanding banking markets. This paper studies the reaction of online banks to changes in federal fund rates. We find that these banks increase rates that they offer on deposits significantly more than traditional banks do. A 100 basis points increase in the federal fund rate leads to a 30 basis points larger in rates of online banks relative to traditional banks. Consistent with the rate movements, online bank deposits experience inflows, while traditional banks experience outflows during monetary tightening in 2022. Results are similar across banking markets of different competitiveness and demographics, but they vary with the stickiness of banking relationships. Our findings shed new light on the role of online banks in interest rate passthrough and the deposit channel of monetary policy.