Several great web frameworks have been introduced over the years. Among them are Svelte and Solid.js. The former was created by Ryan Carniato on November 29, 2016, whereas the latter was created by Rich Harris on October 18, 2020. The commonality between them is that they have challenged traditional web development. However, there are substantial differences between the two. Let's dive into it.

Solid.js is a declarative library that doesn't need the use of a virtual DOM. It is somewhat similar to React and has a unidirectional data flow. But, contrary to React, it provides more control over-reactivity and performance. How? Well, it uses custom hooks and functions. Since Solid.js is built on top of a reactive system, its components only render once. Keep in mind that Solid.js components contain JavaScript functions.

In contrast, Svelte components are made of reusable, self-contained code blocks. Svelte also incorporates reactivity, but its reactivity is built-in and updates automatically. There's no need for manual rendering here.

Now, as far as speed is concerned, Solid.js is faster than Svelte. Why? Well, because of its techniques like optimized DOM list reconciliation. Though Svelte isn't faster, it still outperforms React, Angular, and Vue.

Which one is easier for you to learn? Well, if you already know HTML, CSS, and JavaScript, you won't have difficulty learning Svelte. That's not the case with Solid.js. It's only easy for those web developers who are already familiar with React, as Solid.js is built on almost the same principles and structures. However, when it comes to popularity, Svelte is more popular than Solid.js due to its simplicity, ease of use, and other performance-related advantages. In contrast, Solid.js has a small user base. Nevertheless, it seems that among web developers, Solid.js is gaining popularity. React developers are trying to learn and use Solid.js because of its reactive and lightweight approach.

And even though both frameworks have good documentation, Svelte documentation includes lengthy explanations and examples. It also contains numerous plugins and tools. Companies like Netflix and The New York Times use Svelte, whereas Solid.js is employed by lesser-known companies like Astro. build and Mozilla. However, I am not entirely sure which technology will gain more popularity in the future. Currently, due to its simple syntax and extensive features, Svelte is becoming more popular than Solid.js.