Authentication is at the heart of most web development, yet it is difficult to get right. In this article, Diogo Souza discusses common security problems with authentication systems and how you can resolve them. Even if you never build an authentication system from scratch (you shouldn't), understanding these security concerns will help you make sure whatever authentication system you use is doing its job.

Tests are an integral part of most well-working Rails applications where maintenance isn’t a nightmare and new features are consistently added, or existing ones are improved. Unfortunately, for many applications, a production environment is where they are put under heavy workload or significant traffic for the first time. This is understandable as such tests are costly.