The 17 best web development frameworks for 2021 are discussed in this article. The top frontend frameworks include ReactJS, AngularJS, VueJS, Svelte, Preact, EmberJS, and LitElement, each with their own strengths and weaknesses. For backend development, the popular frameworks include ExpressJS, Next.js, Gatsby, Nuxt, Django, Koa, Nest, Meteor, and Hapi. The choice of framework depends on the project's nature, and it is recommended to consider factors such as performance, scalability, security, and ease of use when selecting a framework. Additionally, tools like LambdaTest can be used to test how websites and web apps render on multiple devices.