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Vaadin for low bandwidth web apps
I live in area where majority of the people access the internet from dial-up modems mostly provided by the loca telcos running EDGE and 3G networks. I'm contemplating building my app using Vaadin due to the fact that I'm good at Java.
My predicament: Is Vaadin good for low bandwidth web apps?
Vaadin load page + default widget set + reindeer theme = about 250 kB. EDGE is 236 kbit/s, so it would take some 10 seconds to load the widget set and other stuff. EDGE also has pretty high latences, around 600 ms I think. Vaadin startup typically requires some 5-10 sequential requests, so that makes 3-6 seconds. So, application start should take around 15 seconds. It's a bit slow but manageable.
The widget set is the biggest file and takes almost 10 seconds to load with EDGE, but it is possible to optimize its size by including only the widgets that you actually use.
With HSDPA, the speeds nowadays usually start from around 2 Mbps and the latencies are around 100-200 ms I think, so the speed is quite sufficient for Vaadin apps.
Notice that, while startup time is longer than with HTML web apps, after that a Vaadin app should need less network bandwidth as it only loads changes to the page.
And note that the initial load size Marko mentioned depends on compression being enabled on the server.