Svelte vs Polymer: A Detailed Comparison

In this tutorial, we will compare two popular JavaScript frameworks, SvelteJS and Polymer, and discuss their differences in terms of syntax, performance, component architecture, data binding, tooling, and community and ecosystem. By the end of this tutorial, you will have a clear understanding of the strengths and weaknesses of each framework, allowing you to make an informed decision when choosing between SvelteJS and Polymer for your web development projects.

sveltejs polymer detailed comparison


SvelteJS and Polymer are both JavaScript frameworks used for building web applications. While they share some similarities, they have distinct differences in terms of syntax, performance, and component architecture.

What is SvelteJS?

SvelteJS is a modern JavaScript framework that focuses on compiling your application at build time to highly optimized, vanilla JavaScript code. This means that instead of shipping a bulky framework to the client's browser, SvelteJS compiles your components into efficient JavaScript code, resulting in faster load times and improved performance.

What is Polymer?

Polymer, on the other hand, is a JavaScript library that allows you to build reusable web components. It provides a set of tools and guidelines to create custom elements that can be used across different web applications. Polymer follows the Web Components standard, making it compatible with modern browsers.


The syntax of a framework plays a crucial role in developer productivity and ease of use. Let's compare the syntax of SvelteJS and Polymer.

SvelteJS Syntax

SvelteJS uses a declarative syntax, similar to HTML, to define components. Here's an example of a simple SvelteJS component:

  let name = 'World';

<h1>Hello {name}!</h1>

<button on:click={() => { name = 'SvelteJS' }}>Change Name</button>

In the above code, we define a component with a reactive variable name and render it inside an <h1> tag. Clicking the button changes the value of name to 'SvelteJS'. The use of curly braces {} allows us to interpolate JavaScript expressions within the HTML-like template.

Polymer Syntax

Polymer also uses a declarative syntax, but it is based on a custom template syntax called Template Binding. Here's an example of a simple Polymer component:

<dom-module id="my-element">
    <h1>Hello {{name}}!</h1>
    <button on-click="changeName">Change Name</button>
    class MyElement extends Polymer.Element {
      static get is() { return 'my-element'; }
      static get properties() {
        return {
          name: {
            type: String,
            value: 'World'
      changeName() { = 'Polymer';
    customElements.define(, MyElement);

In the above code, we define a Polymer element using the <dom-module> tag. The element's template contains the HTML markup, and the associated JavaScript class defines the element's behavior and properties. The name property is defined with a default value of 'World' and is bound to the rendered template. Clicking the button triggers the changeName method, which updates the value of name to 'Polymer'.


Performance is a critical factor in web development, as it directly impacts the user experience. Let's compare the performance of SvelteJS and Polymer.

SvelteJS Performance

SvelteJS's unique approach of compiling components into highly optimized JavaScript code results in excellent performance. Since the framework generates minimal JavaScript code during the build process, the final output is smaller and loads faster. Additionally, SvelteJS leverages fine-grained reactivity, updating only the necessary parts of the DOM when a state change occurs, further improving performance.

Polymer Performance

Polymer's performance depends on the browser's native support for Web Components. While modern browsers have improved their support, there is still some overhead involved in rendering and updating Web Components. Polymer relies on the browser's native capabilities to handle these operations efficiently, which may vary across different browsers. However, Polymer provides polyfills for older browsers to ensure compatibility.

Component Architecture

The component architecture of a framework determines how components are structured and composed. Let's compare the component architecture of SvelteJS and Polymer.

SvelteJS Component Architecture

SvelteJS follows a component-based architecture where each component is self-contained and can be easily composed with other components. Components in SvelteJS consist of a template, JavaScript logic, and styles, all defined within a single file. This approach simplifies component management and encourages reusability.

Polymer Component Architecture

Polymer also follows a component-based architecture, leveraging the Web Components standard. Components in Polymer are defined using the <dom-module> tag, which encapsulates the component's template, JavaScript, and styles. The use of Shadow DOM ensures proper encapsulation and isolation of component styles and behavior.

Data Binding

Data binding allows you to establish relationships between different parts of your application, ensuring that changes in one area automatically reflect in others. Let's compare the data binding capabilities of SvelteJS and Polymer.

SvelteJS Data Binding

SvelteJS supports two-way data binding, which means changes in the data propagate both from the parent component to the child component and vice versa. This is achieved through the use of the bind: directive. Here's an example:

  let name = 'World';

<input bind:value={name} />

<p>Hello {name}!</p>

In the above code, the bind:value directive binds the value of the input field to the name variable. Any changes in the input field will be reflected in the paragraph below.

Polymer Data Binding

Polymer also supports data binding, but it follows a different syntax. Data binding in Polymer is achieved using the double curly braces {{}}. Here's an example:

<dom-module id="my-element">
    <input value="{{name::input}}" />
    <p>Hello {{name}}!</p>
    // ...

In the above code, the value="{{name::input}}" expression establishes a two-way data binding between the input field and the name property. Any changes in the input field will be reflected in the paragraph below, and vice versa.


Tooling plays a crucial role in developer productivity and efficiency. Let's compare the tooling support for SvelteJS and Polymer.

SvelteJS Tooling

SvelteJS provides an official command-line interface (CLI) tool called SvelteKit, which offers a modern development experience. It includes features like hot module reloading, code splitting, server-side rendering, and more. Additionally, SvelteJS has excellent integration with popular editors and IDEs, providing autocompletion, linting, and debugging capabilities.

Polymer Tooling

Polymer does not have an official CLI tool, but it provides a set of tools to aid development. The Polymer CLI allows you to scaffold and build Polymer projects, and it also provides a development server for testing your components. Additionally, Polymer has good editor support, with plugins available for popular editors like Visual Studio Code.

Community and Ecosystem

The community and ecosystem surrounding a framework can greatly impact its adoption and support. Let's compare the community and ecosystem of SvelteJS and Polymer.

SvelteJS Community and Ecosystem

SvelteJS has gained significant popularity in recent years, with a growing community of developers. It has an active ecosystem with numerous libraries and tools being developed by the community. Additionally, SvelteJS has official documentation, tutorials, and a dedicated forum for community support.

Polymer Community and Ecosystem

Polymer has a mature community, although it may not be as active as some other frameworks. It has been around for several years and has a stable ecosystem with various libraries and tools available. Polymer has official documentation, tutorials, and a vibrant community forum to seek help and share knowledge.


In this tutorial, we compared SvelteJS and Polymer in terms of syntax, performance, component architecture, data binding, tooling, and community and ecosystem. Both frameworks have their strengths and weaknesses, and the choice between them depends on your specific requirements and preferences.

SvelteJS stands out for its efficient compilation process, resulting in excellent performance. It also provides a straightforward component architecture and supports two-way data binding. The SvelteJS community is growing rapidly, with an active ecosystem and great tooling support.

Polymer, on the other hand, follows the Web Components standard and provides a solid foundation for building reusable web components. It has good performance, although it depends on the browser's native support for Web Components. Polymer has a mature community and ecosystem, making it a solid choice for web development projects.

Ultimately, the decision between SvelteJS and Polymer should be based on your project's specific requirements, your familiarity with the frameworks, and your development team's preferences.