The top 5 most popular programming languages for web app development are Java, PHP, Python, JavaScript, and Ruby. The robust security features of Java make it a good choice for building banking and fintech web applications. While PHP is suitable for building static and dynamic web projects. Owing to the simplicity of Python code that reduces the development time considerably, this programming language is one of the most preferred options for custom web app development. JavaScript allows the creation of interactive web pages. Finally, Ruby works best for creating e-commerce web applications and minimum viable products.