Test all your code in production using “feature flags”

(written by lawrence krubner, however indented passages are often quotes). You can contact lawrence at: lawrence@krubner.com

I was talking to someone at Viacom, and he told me they were doing something very clever: they use feature flags to limit who can see new features, and in fact, all new features are at first limited to the QA team. Because of this, they have no development servers — everything is tested in production. This allows the testing to be much more realistic.

Feature flag libraries in Ruby and Clojure:

Ruby: rollout

Clojure: shoutout

Source