Before interacting with a web application, it asks a question “who you are?” and to answer this question authentication plays the role. Authentication provides us security and security are one of the most important factors to consider when building a successful web application or web API. You might have developed a beautiful UI for your application, but it doesn’t make sense if you can’t secure your application. Authentication serves to secure a web application layer from attacks by unauthorized users. This paper examines the diverse approaches to implementing authentication in web application and the varying levels at which web application security can be fortified. This paper discusses the weakness in authentication programs of a web application.