This disclosure describes techniques implemented partly by a service provider network for containerizing applications. In an example, the techniques may include determining one or more processes to be included in a containerized version of an application, preparing and initializing a sandbox including at least executable files of the one or more determined processes, monitoring the execution of a particular process of the one or more determined processes in the sandbox to determine one or more dependencies of the particular process, and selecting the one or more dependencies of the particular process to be components of the containerized version of the application.