"Best tech" depends on your requirements. Ease of development, speed, scalability, community? I would go with Python 3 (yes, use 3 when starting a new project)

"Best tech" depends on your requirements. Ease of development, speed, scalability, community? I would go with Python 3 (yes, use 3 when starting a new project) and Flask & Co. because you write less boilerplate code and have a big community. Go is interesting but you might end up with more dead ends and more boilerplate code than Python 3 (yes I know, it's faster than Python but Python has more/bigger [proven to work] libraries/community). If you like Java or Scala go with the Play Framework. Most beautiful documentation of all 3 and it covers more of your "requirements" with its base than Flask (which is a micro framework).