Rocket Cos. said Monday it would pay $1.8 billion in stock for the online real-estate agency Redfin Corp. in an effort to make it easier for customers to buy property using their mobile devices. “We want a customer to be able to check her phone to find out what she can afford,

The mortgage giant Rocket Cos. has agreed to buy Redfin in an all-stock deal valuing the online real-estate brokerage at $1.75 billion.

Rocket Companies agreed to acquire Seattle-based Redfin in a $1.75 billion deal that will bring together the nation's largest mortgage