Axios Interceptors – Pros and common use cases


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Making HTTP requests and handling responses in modern web development is a common task. Axios is a good js library, that simplifies the process by providing a clean API. Interceptors are one of the powerful features offered by Axios. In this blog post, we will explore the need for interceptors for adding JWT token in the request header. On scrolling you can see demonstration and usage of axios interceptors with sample code. Axios interceptors consist of two types: request interceptors and response interceptors. Request interceptors intercept outgoing requests before they are sent to the server, allowing developers to modify the request configuration. This includes adding custom headers, handling authentication, or preprocessing request data.

Why do we need Interceptors?

Interceptors facilitates for handling authentication and authorization mechanisms. It’s viable to connect headers or tokens to every request, making sure that the necessary authentication is blanketed without repetitive manual coding using Interceptors. In case of error dealing with, interceptors will save you repetitive mistakes coping with code in more than one locations. Interceptors can help you rework request facts or response data. You can exchange request payloads, manage response facts codecs, or take care of serialization/deserialization obligations easily. To installation interceptors, developers can define them in an Axios example or globally for all requests. Request interceptors may be applied the usage of the interceptors.request.use technique, which allows developers to intercept and change the request configuration before it is sent. This is mainly useful for including headers, remodeling facts, or injecting authentication tokens.

Notable feature of Axios is its capability to address request and reaction interceptors. Interceptors act as middleware, allowing developers to intercept and regulate requests and responses before they’re sent or obtained. This characteristic is in particular beneficial for responsibilities like adding custom headers, transforming request or response information, or dealing with mistakes in a centralized manner.

Axios supports the cancellation of requests, that’s crucial in situations wherein a request will become needless or needs to be aborted. It offers a easy API for canceling ongoing requests, stopping needless community traffic and liberating up resources.

Furthermore, Axios has integrated guide for coping with response records in various formats, which include JSON, XML, and FormData. It can robotically parse the response records and offer it in a convenient layout for similarly processing.

With its simplicity, flexibility, and substantial feature set, Axios has come to be a popular desire for developers in terms of managing HTTP requests in web development. Whether operating on browser-primarily based programs or server-aspect Node.Js projects, Axios gives a regular and dependable solution for efficient communique with servers.

How to setup a request interceptor in a project:

Installation of Axios bundle is achieved with the aid of running the npm command in the terminal.

npm i axios

After a success installation, dependency assets is appears with a brand new belongings in it as:

"axios": "^1.4.0"

Let’s recall an instance of the usage of Axios interceptors to handle authentication tokens for API requests. For lessen repetation and neet code right here we create seperate file that introduce interceptors to other documents. Consider file path as


In side the ts file

import axios from 'axios';

  (config) => {
    const token = localStorage.getItem('token');
    if (token) {
      config.headers['Authorization'] = `Bearer ${token}`;
    return config;
  (error) => {
    return Promise.reject(error);

export default axios;

This code snippet can be used within the login authentication system of an application. It demonstrates the usage of Axios interceptors to enhance the functionality of outgoing requests in an internet application. By putting in place a request interceptor, the code intercepts each outgoing request earlier than it’s far sent and modifies it by including an authorization header. This header consists of a token retrieved from the nearby storage, taking into account authentication and authorization of the request. The interceptor feature exams if a token exists, and if so, it provides the authorization header with the token value in the standardized “Bearer token” format. This method gives a continuing way to encompass authentication information in each request, ensuring that authorized requests can get admission to covered assets at the server. By centralizing this logic within the interceptor, developers can keep their codebase easy and organized, while additionally reaching steady and secure communication with the server. For instance, When a person logs in to the application, a JWT token is created and saved inside the neighborhood storage. This stored token is then appended to every request as a header assets. By the usage of interceptors, any unauthorized get admission to the API from other programs may be rejected based on the absence of the bearer token within the header.

Once the code has been done. This identical code can be use unique pages by means of importing this as

import axios from "../plugins/axios.ts";

// Usage example: Making an API request
  .then(response => {
	console.log('API Response:', response.data);
  .catch(error => {
	console.log('API Error:', error);

Real-World Use Cases

Authentication and authorization are critical additives of maximum internet programs. Intercepting requests the usage of Axios interceptors permits developers to add authentication headers, control access tokens, and deal with unauthorized requests. By mechanically injecting the essential authentication facts, interceptors make certain that every request is authorized and secure. This centralized technique simplifies the implementation of authentication-related good judgment and complements the overall security of the utility.

Furthermore, interceptors facilitate API logging and debugging. By taking pictures request and reaction details, developers gain treasured insights into community visitors, which aids in studying mistakes, troubleshooting issues, and optimizing overall performance. Intercepting requests allows for custom logging, allowing developers to song and screen API utilization, hit upon anomalies, and make certain compliance with installed suggestions.

Limitations and Drawbacks

While Axios interceptors offer a effective mechanism for handling and enhancing requests and responses in web programs, they also have a few limitations and disadvantages that developers should be privy to. Understanding these barriers can assist in making informed decisions and enforcing suitable answers when working with interceptors. Let’s discover some of the not unusual obstacles and drawbacks of Axios interceptors:

  1. Global Scope: Intercepting requests and responses the use of Axios interceptors applies globally to all requests made via Axios. This manner that interceptors can affect all requests in an utility, even if they are no longer supposed to be intercepted or modified. This global scope can cause sudden behavior and ability conflicts whilst multiple interceptors are in use, even though you can exempt certain requests.
  1. Order of Execution: Axios interceptors are carried out within the order they’re defined. This order of execution may be significant, in particular when multiple interceptors are concerned. It is crucial to don’t forget the sequence of interceptors to make sure that they are carried out within the favored order.

For instance, if an interceptor modifies a request based totally on a few condition and another interceptor is predicated on the modified request, the order of execution becomes critical. If the interceptors are not prepared properly, the conduct of the software may not align with the meant common sense.

To address this hindrance, developers need to carefully plan and define the order of interceptors. They need to remember dependencies among interceptors and design them for that reason to make sure the expected conduct.

  1. Lack of Fine-Grained Control: Axios interceptors perform at a high degree and provide restricted great-grained manipulate over specific parts of requests and responses. While interceptors can adjust headers, request records, and reaction records, they may now not provide granular manipulate over character fields or elements within the requests or responses.

In a few cases, developers may additionally require greater specific manipulate over precise elements of the request or reaction that can’t be finished totally via interceptors. In such eventualities, additional customization or coping with can be essential outside the scope of interceptors.

To conquer this drawback, developers can integrate interceptors with other strategies or mechanisms to reap the preferred stage of manipulate. This may also involve guide manipulation of the request or reaction records after interception or using more particular libraries or gear for high-quality-grained adjustments.

  1. Error Handling Challenges: Intercepting mistakes with Axios interceptors can every now and then present challenges. While interceptors can deal with errors in a centralized manner, they’ll no longer continually capture all possible blunders eventualities or provide targeted information approximately the specific mistakes that happened.

For example, interceptors won’t have get admission to to the total blunders stack hint or specific errors messages which could help with debugging and troubleshooting. This can make it extra challenging to perceive and deal with precise mistakes in the application.

To mitigate this obstacle, developers can combine interceptors with dedicated error coping with mechanisms and logging equipment. This permits for shooting and logging specified errors information outdoor of the interceptors, offering higher insights into the specific errors scenarios.

  1. Compatibility with Third-Party Libraries: Axios is a extensively used library, but it is able to no longer usually be completely compatible with different third-party libraries or frameworks. When integrating Axios interceptors into an existing codebase or operating with different libraries, conflicts or compatibility problems can stand up.

It is vital to thoroughly check the combination of Axios interceptors with different libraries and frameworks to ensure seamless capability. Additionally, staying updated with the ultra-modern variations of Axios and different associated libraries can assist deal with any compatibility issues that can arise.


With the capacity to feature authentication headers, manipulate get entry to tokens, and handle unauthorized requests seamlessly, interceptors play a crucial role in enhancing protection and user experience. As developers include Axios and its effective interceptors, they unlock a world of possibilities for green and strong request dealing with of their net packages.

If you have got any doubts inside the JWT token era and validation, then test and make clear the technique in JWT Authentication in Node.js with Middleware: A Secure Approach for Web Applications – Journals (zweck.io)

Happy coding with Axios and revel in the benefits of interceptors to your next web improvement project!😊

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