How does a bridge loan or rent-back work?

A bridge loan lets a homeowner borrow against equity in their current home to fund a down payment on the next one before the first home actually sells, then gets repaid once that sale closes. A rent-back does something similar without new debt: the seller stays in the home after closing and pays the buyer rent for an agreed period, buying time to move. Both tools solve the same timing problem between selling one home and buying another, just through different mechanics.