What it is
Axios is a library for HTTP requests from browsers and Node.js. It appeared before `fetch` became the familiar standard and remains useful when requests need to be centrally configured rather than simply sent.
The library is promise-based, can create separate client instances, supports request and response interceptors, cancellation through AbortController, data transforms, file uploads, progress, and detailed header configuration.
How it appeared and why it stuck
In large JavaScript applications, HTTP requests quickly turn into repeated code: base URLs, tokens, error handling, timeouts, and repeated headers. Axios became popular because it wrapped that routine in a convenient API.
Even after `fetch` became common, Axios kept a place. It provides one API for browser and Node.js usage, a familiar response shape, interceptors, and many patterns teams have used for years.
What is inside
The repository contains the client source, adapters, types, tests, and documentation for request configuration, error handling, cancellation, form serialization, and HTTP/2.
Client instance with an interceptor
This example shows a common pattern: one client stores the base URL, while an interceptor adds a header before each request.
import axios from "axios";
const api = axios.create({
baseURL: "https://api.example.com",
timeout: 5000
});
api.interceptors.request.use((config) => {
config.headers.Authorization = `Bearer ${localStorage.getItem("token")}`;
return config;
});
const { data } = await api.get("/profile");Where it helps
Axios helps in applications with many requests and shared behavior: authorization, error handling, retries, timeouts, file uploads, and forms.
If an app makes one simple GET request, standard `fetch` is enough. But when requests become part of application architecture, a separately configured client is often cleaner.
Strengths and limits
The strength is a mature API and predictable HTTP wrapper. Teams get one way to describe requests and responses across environments.
The limitation is that it is an extra dependency on top of the platform. New projects should compare Axios with `fetch` deliberately: sometimes the library is justified, sometimes the standard API is enough.