Software developers code programs based on an engineer or architects specs. They normally come from a scale up coding facility. Don't not all think about future selves but how to get things done right now. Usually understand business goals pretty well.
Software engineers have a deep knowledge for common design patterns, probabilistic programming, and semi-fast prototyping. They also shine bright when data mining or artifical intelegence comes into play. Not normally very focused on the business goals, but strive to know more. Normally hired directly out of college or after 5+ years experience as a normal developer.
Software architects do little coding but are normally software engineers on steroids. They have a vast knowledge and understanding for how systems work together along with having around 15 years of SEexperience. Normally they have a good understanding and connection to the businesses success.