Useful at Night is a mobile guide for nightlife empowering real time discovery of cool locations, allowing nightlife players to identify opinion leaders. Through geo-location and data aggregation capabilities, the application allows useful exploration of cities, places and parties.
Evelin Velev was kind enough to share what technologies his team uses to run their star-up.
Main technologies used are Node.js, HTML 5 and NoSQL.
Their mobile front-end supports both iOS and Android platforms and is built using HTML5 and a homemade UI framework called RAPID. There are some native parts developed in Objective-C and Java respectively.
In addition Useful at Night uses MongoDB for metrics data with a custom metrics solution written in Node.js; Amazon S3 for storing different assets; and a custom storage solution called Divan (simple CouchDB like).
Why Not Something Else?
We chose Node.js for our application servers, because it enables us to build efficient distributed systems while sharing significant amounts of code between client and server. Things get really interesting when you couple Node.js with Redis for data structure sharing and message passing, as the two technologies play very well together.
We chose CouchDB as our main back-end because it is the most schema-less data-store that supports secondary indexing. Once you get fluent with its map-reduce views, you can compute an index out of practically anything. For comparison, even MongoDB requires that you design your documents as to enable certain indexing patterns. Put otherwise, we'd say CouchDB is a data-store that enables truly lean engineering - we have never had to re-bake or migrate our data since day one, while we're constantly experimenting with new ways to index, aggregate and query it.
We chose HTML5 as our front-end technology, because it's cross-platform and because we believe it's ... almost ready. Things are still really problematic on Android, but iOS boasts a gorgeous web presentation platform, and Windows 8 is also joining the game with a very good web engine. Obviously we're constantly running into issues and limitations, mostly related to the unfortunate fact that in spite of some recent developments, a web app is still mostly single threaded. However, we're getting there, and we're proud to say we're running a pretty graphically complex hybrid app with near-native GUI performance on the iPhone 4S and above.
Want More Info?
If you'd like to hear more from Useful at Night please comment below. I will ask them to follow this thread and reply to your questions.