Express.js, or simply Express, is a back end

web application framework A web framework (WF) or web application framework (WAF) is a software framework that is designed to support the development of web applications including web services, web resources, and web APIs. Web frameworks provide a standard way to build an ...

for building

REST Rest or REST may refer to: Relief from activity * Sleep ** Bed rest * Kneeling * Lying (position) * Sitting * Squatting position Structural support * Structural support ** Rest (cue sports) ** Armrest ** Headrest ** Footrest Arts and enter ...

ful APIs with

Node.js Node.js is an open-source server environment. Node.js is cross-platform and runs on Windows, Linux, Unix, and macOS. Node.js is a back-end JavaScript runtime environment. Node.js runs on the V8 JavaScript Engine and executes JavaScript code o ...

, released as free and open-source software under the

MIT License The MIT License is a permissive free software license originating at the Massachusetts Institute of Technology (MIT) in the late 1980s. As a permissive license, it puts only very limited restriction on reuse and has, therefore, high license comp ...

. It is designed for building

web application A web application (or web app) is application software that is accessed using a web browser. Web applications are delivered on the World Wide Web to users with an active network connection. History In earlier computing models like client-serv ...

s and

API An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how ...

s. It has been called the

de facto standard A ''de facto'' standard is a custom or convention that has achieved a dominant position by public acceptance or market forces (for example, by early entrance to the market). is a Latin phrase (literally " in fact"), here meaning "in practice b ...

server framework for

. The original author, TJ Holowaychuk, described it as a

Sinatra Francis Albert Sinatra (; December 12, 1915 – May 14, 1998) was an American singer and actor. Nicknamed the "Chairman of the Board" and later called "Ol' Blue Eyes", Sinatra was one of the most popular entertainers of the 1940s, 1950s, and ...

-inspired server, meaning that it is relatively minimal with many features available as plugins. Express is the back-end component of popular development stacks like the

MEAN There are several kinds of mean in mathematics, especially in statistics. Each mean serves to summarize a given group of data, often to better understand the overall value (magnitude and sign) of a given data set. For a data set, the '' ari ...

, MERN or MEVN stack, together with the

MongoDB MongoDB is a source-available cross-platform document-oriented database program. Classified as a NoSQL database program, MongoDB uses JSON-like documents with optional schemas. MongoDB is developed by MongoDB Inc. and licensed under the Ser ...

database software and a

JavaScript JavaScript (), often abbreviated as JS, is a programming language that is one of the core technologies of the World Wide Web, alongside HTML and CSS. As of 2022, 98% of websites use JavaScript on the client side for webpage behavior, of ...

front-end framework or library.

History

Express.js was founded by TJ Holowaychuk. The first release, according to Express.js's

GitHub GitHub, Inc. () is an Internet hosting service for software development and version control using Git. It provides the distributed version control of Git plus access control, bug tracking, software feature requests, task management, continu ...

repository, was on 22 May 2010. Version 0.12 In June 2014, rights to manage the project were acquired by StrongLoop. StrongLoop was acquired by IBM in September 2015; in January 2016, IBM announced that it would place Express.js under the stewardship of the Node.js Foundation incubator.

Features

* Robust routing * Concentrate on high-performance * HTTP helpers (redirection, caching, etc)

Popularity

Express.js is used by

Fox Sports Fox Sports is the brand name for a number of sports channels, broadcast divisions, programming, and other media around the world. The ''Fox Sports'' name has since been used for other sports media assets. These assets are held mainly by the F ...

PayPal PayPal Holdings, Inc. is an American multinational financial technology company operating an online payments system in the majority of countries that support online money transfers, and serves as an electronic alternative to traditional paper ...

Uber Uber Technologies, Inc. (Uber), based in San Francisco, provides mobility as a service, ride-hailing (allowing users to book a car and driver to transport them in a way similar to a taxi), food delivery (Uber Eats and Postmates), packa ...

and IBM.

Example

The following program will respond to

HTTP GET The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, w ...

requests with the text 'Hi, your request has been received', and listen to the port the program is running on; Port 2000, in this case. // Import the Express library. const express = require('express'); // Initializing the app. const app = express(); // Getting the path request and sending the response with text app.get('/', (req,res) => ); // Listen on port 2000 app.listen(2000, () => );

References

External links