Both MEAN and MERN are full-stack frameworks that have Java-coded components. The common technologies in both the stacks are Mongo DB, ExpressJS and NodeJS. The obvious difference that’s evident from the names is in the third letter of each acronym. MEAN makes use of Angular JS which is developed by Google whereas MERN uses the React JS developed by Facebook. Both aid developers to create reactive and intuitive UI.
MEAN is a JavaScript framework that is used to build dynamic web applications or websites. The same programming language can be used to build both server-side as well as client-side applications. This is because all the MEAN stack components support JavaScript.
On the other hand, MERN is an open-source JavaScript library. It is a group of JavaScript-based frameworks, databases, and runtime environments. It is created to provide a smoother development process. This tech stack provides an end-to-end framework to developers, as the front end or the UI is developed using React framework.
MEAN uses Typescript language while MERN uses JavaScript or JSX. Popularity-wise, Angular has been popular for the past few years but React is taking over.
