Internet in Iran is expensive, unstable and regulated. 10 mbps of home unlimited internet will cost you around 70$. It's even more expensive for business, though in all the trendy cafes listed here internet is good enough to work comfortably.
It's possible to stumble upon good coffee in Tehran even unintentionally. Most of all coffee shops are also the destination for good food, it's difficult to separate coffee shops and restaurants.
The best new cafe in town popped up in fall 2015. All the young professionals gather here, every evening I met people from startup-scene, architects, designers and other creatives here. Everyone speaks decent English. Coffee is good. Food is great and portions are huge, but not so many vegetarian options.
I'm coming back to Tehran in February 2016 to work with Iranian tech start-ups. Any suggestions to make this article better are highly appreciated, feel free to drop me a line.