JavaScript Frameworks

What Are JavaScript Frameworks?

Every web application has to solve the same groundwork before it can do anything specific to its business, such as keeping the screen in sync with data and moving between pages without a full reload. A framework solves that groundwork once, so a team spends its time on the features no one else has built.

JavaScript is the language browsers run, and 66% of respondents to Stack Overflow's 2025 Developer Survey reported using it, more than any other language. That reach is why its frameworks now extend well past the browser. React and Vue build user interfaces, Express and NestJS run server code on Node.js, React Native builds mobile apps, and Electron packages web code as desktop apps.

The term covers tools of very different sizes. Angular ships with routing and form handling built in. React handles only the interface layer and leaves the rest to separate packages, which is why its own documentation calls it a library. In everyday use, most teams call both frameworks, and this entry follows that usage.

Why Does the Choice of JavaScript Framework Matter?

• The choice outlasts the people who made it. A framework sets the structure of every file in the codebase, so switching later usually means a rewrite. Teams that built on AngularJS faced exactly that when Google ended its support on December 31, 2021, because modern Angular is a separate framework with no direct upgrade path.

• It decides who you can hire. Developers specialize by framework. A team on React draws from the largest pool of experienced developers, while a team on a niche framework may wait longer to fill each role.

How Do JavaScript Frameworks Work?

• Inversion of control. With a library, your code calls the library when it needs something. With a framework, the framework runs the application and calls your code at defined points, such as when a page loads or a user clicks a button.

• Components. Interface frameworks split the screen into self-contained components, each holding its own markup and logic. A product page might combine a gallery component with a checkout button component, and both can be reused on other pages.

• Reactivity. When data changes, the framework works out which parts of the screen depend on it and updates only those. React does this by comparing a virtual copy of the page against the previous one, while Svelte compiles components into code that updates the page directly.

• Routing. The framework maps URLs to screens, so moving between pages happens in the browser without reloading the whole page. This is the basis of a single page application.

• Server-side rendering. Meta-frameworks like Next.js and Nuxt run the same components on a server to send finished HTML first, which speeds up the first load and helps search engines index the page.

• Build step. Most frameworks need a build tool to turn component files into plain JavaScript the browser can run, compressing the code along the way.

Which JavaScript Frameworks Do Teams Use?

Figures below are the share of respondents to Stack Overflow's 2025 Developer Survey who used each tool in the past year.

User interface frameworks. React (44.7%), Angular (18.2%), and Vue.js (17.6%) lead this category. Svelte (7.2%) is a smaller alternative that compiles components into optimized JavaScript ahead of time, so less framework code ships to the browser.

Meta-frameworks. Next.js (20.8%) builds on React and Nuxt (4%) builds on Vue. Both add routing and server-side rendering on top of the interface framework.

Server-side frameworks. Express (19.9%) is a minimal web framework for Node.js. NestJS (6.7%) adds an Angular-style structure that suits larger backend codebases.

What Are the Key Characteristics of JavaScript Frameworks?

• Opinionated or flexible. Angular and NestJS prescribe how an application should be structured. React and Express leave most of those decisions to the team. Opinionated frameworks keep large teams consistent, while flexible ones adapt more easily to unusual requirements.

• Fixed support windows. Major versions retire on a schedule. Vue 2 reached end of life on December 31, 2023, and teams still running it stopped receiving security fixes from that date.

• Open source with corporate backing. The leading frameworks are free and open source. Meta maintains React and Google maintains Angular, while Vue is led by its creator Evan You and funded by sponsors.

• Built on the npm registry. Frameworks are installed from npm along with their dependencies, so a typical project pulls in many third-party packages the team never reviews line by line.

What Are the Benefits of Using a JavaScript Framework?

• Faster first release. Routing and state handling come ready-made, so a team starts on product features instead of rebuilding groundwork every project needs.

• Shared conventions. A developer who knows the framework can find their way around an unfamiliar codebase quickly, because files and patterns follow the same rules.

• Safer defaults. React and Angular escape text before inserting it into the page, which blocks a common class of cross-site scripting attacks without extra code.

• Tested at scale. A widely adopted framework has most of its bugs found and fixed by other teams first, so a team inherits fixes it never had to discover.

• One language across the stack. With React on the client and Express or NestJS on the server, a team writes both sides in JavaScript or TypeScript and can share validation code between them.

What Are the Challenges of Using a JavaScript Framework?

• Lock-in. Business logic tends to get tangled with framework code over time. Keeping core logic in plain TypeScript modules makes a future migration cheaper, but adds layers that slow down early development.

• Forced upgrades. Support windows close whether a team is ready or not. Staying current means scheduling upgrade work as a regular cost, and paying for extended commercial support is the main alternative to doing that work.

• Bundle size. Framework code downloads to every user before the app can start. Lighter frameworks or server rendering reduce that cost, but narrow the choice of compatible libraries or add server infrastructure to run.

• Dependency risk. Every package a framework pulls in is code the team did not write. Automated scanning catches known vulnerabilities, but adds alert triage to the team's regular workload.

What Is the Difference Between a JavaScript Framework and a JavaScript Library?

The practical test is replacement cost: if removing a tool would mean rewriting most of the codebase, the team is using it as a framework, whatever its documentation calls it.