Access Control Origin Header error using Axios

I'm making an API call using Axios in a React Web app. However, I'm getting this error in Chrome:

> none > XMLHttpRequest cannot load > https://example.restdb.io/rest/mock-data. No > 'Access-Control-Allow-Origin' header is present on the requested > resource. Origin 'http://localhost:8080' is therefore not allowed > access. >

{
    axios
      .get("https://example.restdb.io/rest/mock-data", {
        headers: {
          "x-apikey": "API_KEY",
        },
        responseType: "json",
      })
      .then((response) => {
        this.setState({ tableData: response.data });
      });
}

I have also read several answers on Stack Overflow about the same issue, titled Access-Control-Allow-Origin but still couldn't figure out how to solve this. I don't want to use an extension in Chrome or use a temporary hack to solve this. Please suggest the standard way of solving the above issue.

After trying out few answers I have tried with this,

headers: { 
  'x-apikey': '59a7ad19f5a9fa0808f11931',
  'Access-Control-Allow-Origin' : '*',
  'Access-Control-Allow-Methods':'GET,PUT,POST,DELETE,PATCH,OPTIONS',
},

Now I get the error as,

> none >Request header field Access-Control-Allow-Origin is not > allowed by Access-Control-Allow-Headers in preflight response >

I'll have a go at this complicated subject.

What is origin?

The origin itself is the name of a host (scheme, hostname, and port) i.g. https://www.google.com or could be a locally opened file file:// etc.. It is where something (i.g. a web page) originated from. When you open your web browser and go to https://www.google.com, the origin of the web page that is displayed to you is https://www.google.com. You can see this in Chrome Dev Tools under Security:

The same applies for if you open a local HTML file via your file explorer (which is not served via a server):

What has this got to do with CORS issues?

When you open your browser and go to https://website.com, that website will have the origin of https://website.com. This website will most likely only fetch images, icons, js files and do API calls towards https://website.com, basically it is calling the same server as it was served from. It is doing calls to the same origin.

If you open your web browser and open a local HTML file and in that html file there is javascript which wants to do a request to google for example, you get the following error:

The same-origin policy tells the browser to block cross-origin requests. In this instance origin null is trying to do a request to https://www.google.com (a cross-origin request). The browser will not allow this because of the CORS Policy which is set and that policy is that cross-origin requests is not allowed.

Same applies for if my page was served from a server on localhost:

Localhost server example

If we host our own localhost API server running on localhost:3000 with the following code:

const express = require('express')
const app = express()
 
app.use(express.static('public'))

app.get('/hello', function (req, res) {
    // res.header("Access-Control-Allow-Origin", "*");
    res.send('Hello World');
})
 
app.listen(3000, () => {
    console.log('alive');
})

And open a HTML file (that does a request to the localhost:3000 server) directory from the file explorer the following error will happen:

Since the web page was not served from the localhost server on localhost:3000 and via the file explorer the origin is not the same as the server API origin, hence a cross-origin request is being attempted. The browser is stopping this attempt due to CORS Policy.

But if we uncomment the commented line:

const express = require('express')
const app = express()
 
app.use(express.static('public'))

app.get('/hello', function (req, res) {
    res.header("Access-Control-Allow-Origin", "*");
    res.send('Hello World');
})
 
app.listen(3000, () => {
    console.log('alive');
})

And now try again:

It works, because the server which sends the HTTP response included now a header stating that it is ok for cross-origin requests to happen to the server, this means the browser will let it happen, hence no error.

How to fix things (One of the following)

• Serve the page from the same origin as where the requests you are making reside (same host).
• Allow the server to receive cross-origin requests by explicitly stating it in the response headers.
• If using a reverse proxy such as NGINX, configure NGINX to send response headers that allow CORS.
• Don't use a browser. Use cURL for example, it doesn't care about CORS Policies like browsers do and will get you what you want.

Example flow

Following is taken from: https://web.dev/cross-origin-resource-sharing/#how-does-cors-work

Remember, the same-origin policy tells the browser to block cross-origin requests. When you want to get a public resource from a different origin, the resource-providing server needs to tell the browser "This origin where the request is coming from can access my resource". The browser remembers that and allows cross-origin resource sharing.

• Step 1: client (browser) request When the browser is making a cross-origin request, the browser adds an Origin header with the current origin (scheme, host, and port).

• Step 2: server response On the server side, when a server sees this header, and wants to allow access, it needs to add an Access-Control-Allow-Origin header to the response specifying the requesting origin (or * to allow any origin.)

• Step 3: browser receives response When the browser sees this response with an appropriate Access-Control-Allow-Origin header, the browser allows the response data to be shared with the client site.

More links

Here is another good answer, more detailed as to what is happening: https://stackoverflow.com/a/10636765/1137669

If your backend support CORS, you probably need to add to your request this header:

headers: {"Access-Control-Allow-Origin": "*"}

[Update] Access-Control-Allow-Origin is a response header - so in order to enable CORS - you need to add this header to the response from your server.

But for the most cases better solution would be configuring the reverse proxy, so that your server would be able to redirect requests from the frontend to backend, without enabling CORS.

You can find documentation about CORS mechanism here: https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS

I had a similar problem and I found that in my case the withCredentials: true in the request was activating the CORS check while issuing the same in the header would avoid the check:

Reason: expected ‘true’ in CORS header ‘Access-Control-Allow-Credentials’

Do not use

withCredentials: true

but set

'Access-Control-Allow-Credentials':true

in the headers.

I had the same error. I solved it by installing CORS in my backend using npm i cors. You'll then need to add this to your code:

const cors = require('cors');
app.use(cors());

This fixed it for me; now I can post my forms using AJAX and without needing to add any customized headers.

For Spring Boot - React js apps I added @CrssOrigin annotation on the controller and it works:

@CrossOrigin(origins = {"http://localhost:3000"})
@RestController
@RequestMapping("/api")

But take care to add localhost correct => 'http://localhost:3000';, not with '/' at the end => 'http://localhost:3000/';, this was my problem.

Using the Access-Control-Allow-Origin header to the request won't help you in that case while this header can only be used on the response...

To make it work you should probably add this header to your response.You can also try to add the header crossorigin:true to your request.

First of all, CORS is definitely a server-side problem and not client-side but I was more than sure that server code was correct in my case since other apps were working using the same server on different domains. The solution for this described in more details in other answers.

My problem started when I started using axios with my custom instance. In my case, it was a very specific problem when we use a baseURL in axios instance and then try to make GET or POST calls from anywhere, axios adds a slash / between baseURL and request URL. This makes sense too, but it was the hidden problem. My Laravel server was redirecting to remove the trailing slash which was causing this problem.

In general, the pre-flight OPTIONS request doesn't like redirects. If your server is redirecting with 301 status code, it might be cached at different levels. So, definitely check for that and avoid it.

You can create a new instance of axios with a custom config, and then use this new configured instance,
create a file with axios-configure.js, add this sharable exported method and use this preconfigured import, rather importing axios directly like we use traditionally,

import axios from 'axios';
import baseUrl from './data-service';

const app = axios.create({
    baseURL: baseUrl,
    headers: {
        'Access-Control-Allow-Origin': '*',
        'Content-Type': 'application/json',
    },
    withCredentials: true
})

export default app;

use this exported function like,

import axios from '../YOUR_DIRECTORY/axios-configure';
axios.get();// wont throw cors

dont import axios from axios;
then use axios.get() it will dont throw cors worked for us,

NOTE this solution will work for them who facing CORS at local environment as local starts at 5000 and backend at 8080, but in production, build gets deployed from java 8080 no CORS in productions (Facing CORS at only local environment)

I had a similar problem when I tried to create the React Axios instance.

I resolved it using the below approach.

const instance = axios.create({
  baseURL: "https://jsonplaceholder.typicode.com/",
  withCredentials: false,
  headers: {
    'Access-Control-Allow-Origin' : '*',
    'Access-Control-Allow-Methods':'GET,PUT,POST,DELETE,PATCH,OPTIONS',
    }
});

npm i cors
const app = require('express')()
app.use(cors())

Above code worked for me.

I imagine everyone knows what cors is and what it is for. In a simple way and for example if you use nodejs and express for the management, enable it is like this

Dependency:

https://www.npmjs.com/package/cors

app.use (
   cors ({
     origin: "*",
    ... more
   })
);

And for the problem of browser requests locally, it is only to install this extension of google chrome.

Name: Allow CORS: Access-Control-Allow-Origin

https://chrome.google.com/webstore/detail/allow-cors-access-control/lhobafahddgcelffkeicbaginigeejlf?hl=es

This allows you to enable and disable cros in local, and problem solved.

After a long time of trying to figure out how CORS works. I tried many way to fix it in my FE and BE code. Some ways CORS errors appearance, some ways the server didn't receive body from client, and other errors...

And finally got this way. I'm hoping this can help someone:

BE code (NodeJS + Express)

var express = require("express");
const cors = require("cors");

var app = express();
app.use(
  cors({
    origin: "*",
  })
);

app.use(function (req, res, next) {
  res.header("Access-Control-Allow-Origin", "*");
  next();
});

// your routers and codes 

My FE code (JS):

fetch(url, {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      Connection: 'Keep-Alive',
      Authorization: `Bearer test`,
    },
    body: JSON.stringify(data),
  });

For any one who used cors package change

 const cors = require('cors');    
 app.use(cors());

to

const cors = require('cors');  
app.use(cors({credentials: true, origin: 'http://localhost:5003'}));

change http://localhost:5003 to your client domain

As I understand the problem is that request is sent from localhost:3000 to localhost:8080 and browser rejects such requests as CORS. So solution was to create proxy

My solution was :

import proxy from 'http-proxy-middleware'
app.use('/api/**', proxy({ target: "http://localhost:8080" }));

$ npm install cors

After installing cors from npm add the code below to your node app file. It solved my problem.

var express = require('express')
var cors = require('cors')
var app = express()
 
app.use(cors())

try it proxy package.json add code:

"proxy":"https://localhost:port"

and restart npm enjoy

same code

const instance = axios.create({
  baseURL: "/api/list", 
 
});

In node js(backend), Use cors npm module

$ npm install cors

Then add these lines to support Access-Control-Allow-Origin,

const express = require('express')
const app = express()
app.use(cors())
app.get('/products/:id', cors(), function (req, res, next) {
            res.json({msg: 'This is CORS-enabled for a Single Route'});
});

You can achieve the same, without requiring any external module

app.use(function(req, res, next) {
            res.header("Access-Control-Allow-Origin", "*");
            res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
            next();
});

 },
  "proxy": "http://localhost:8080",
  "devDependencies": {

use proxy in package.json