The stable assignment problem, introduced in the 1960s by David Gale and Lloyd Shapley, has recently elicited new interest due to its applications in public school assignment and a new, nonatomic framing that relates stable school assignments to market-clearing cutoff vectors. I introduce DeferredAcceptance, a Julia package for solving and analyzing school-choice problems. It provides several variations of the discrete Gale-Shapley and top-trading cycles algorithms, as well as a trio of memory-efficient algorithms for computing an equilibrium in nonatomic admissions markets. In the discrete case, while there are some open-source tools available for running the basic form of the Gale-Shapley algorithm, DeferredAcceptance enables seamless comparison of a variety of assignment procedures for given market data. In the nonatomic case, DeferredAcceptance provides school-demand functions based on the multinomial logit choice model and a variety of scoring schemes; it also permits a user-defined demand function, enabling simulation of a wide range of competitive scenarios.