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Test CORS

See if CORS requests is allowed or blocked in your browser?
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About

Cross-Origin Resource Sharing or CORS is a technique to tell the browser whether a web website/application can fetch resources from a different domain or not. Whether you are testing a web app or developing a website, CORS may be needed. Use this website to see if CORS is allowed in your browser or not.

Test CORS requests in your browser

Click the below buttons to test whether CORS requests is allowed or blocked in your browser.
Note: available methods are GET, PUT, POST, HEAD, DELETE and OPTIONS.
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Description

What is Test CORS?

Test CORS is a web app to tell you whether cross-origin resource sharing is allowed in your browser or not. It simply fetched the "example.com" page from the current domain with several XMLHttpRequest methods and checks whether the fetch request has been successful or not. CORS can be set for methods such as GET, PUT, POST, HEAD, DELETE and OPTIONS. Simply click on the desired method from the above table and wait to see the results.

What is CORS?

CORS stands for Cross-Origin Resource Sharing. It tells your browser whether it can load data from a different domain or not (different from top domain). For example, if your top domain is domain-a.com, and you have a resource within the page from domain-b.com, the CORS policy will tell your browser whether resources from domain-b.com should be loaded or not. In general, many websites have strict CORS policies that tell browsers to block loading their resources in different domains. But, in some situations, for example in web development or app testing, you may need to test something in cross domains. Therefore, the CORS policy needs to be enabled temporarily.

How can I allow CORS in my browser?

Many addons/plugins allow you to enable CORS requests in your browser. Please head to Chrome, Firefox or Opera add-on stores and search for the - allow cors - keyword. Choose a desired extension from the list, and then add it to your browser. Then click on a test CORS button above. Repeat this procedure once the addon is disabled as well and compare the results. Please note that try to keep the CORS add-on disabled all the time and only use it once you need it; because many websites may encounter errors or facing problems if CORS is enabled in your browser.

More about CORS

Often on web pages, we observe the requests made by servers along with the load resources on other servers. The third-party requests may have permission to load the page’s assets such as images, any special fonts, videos, etc. that might be originated from another server. These requests should not be ignored and should never be let go unchecked as these are often corrupted with security errors and viruses dangerous for your computer or program. Another thing to keep in mind is to be aware of some webpages that allow blind download of malicious code which can be a high-security breach in your program and can induce many dangerous problems. Often these resources are not from the main server, but third-party servers that get called when you are connected to a server.

What do we understand by a Security Policy?

Security Policies are designed to reduce the risk of malicious interruption of code through webpages and blind viruses. Usually, servers host the webpages and applications as well as load assets like images, etc. Using a browser not only makes you vulnerable to the risks of security breaches but also involves the risk of requests from hosted-resources that are from different unknown servers. What security policies do is protect you from any risky servers and possible malicious code coming in from another server. It is important to understand that the absence of a security policy header since the server is allowed to load any sort of resources from other domains, it could result in many risks. These risks can damage the entire code of a program, invade your privacy of data among many other unfortunate possibilities. The best and most recommended security policies are the ones that provide the users with a combination of the same origin access only as well as being not excessively limited. Cross-origin resource sharing standard is the keyword that is used for limiting security policies; often abbreviated as CORS.

Cross-Origin Resource Sharing

To understand CORS, it is important to know first about a cross-origin request. This is the request made for a resource outside of an origin usually involving images, fonts, etc. CORS is responsible for the management of all cross-origin requests, protecting your security while dealing with requests.

Importance of CORS

CORS is necessary for connecting to servers and loading resources because it saves your assets from any malicious interruption, as well as provides you easy access to multiple sources across the internet. Most websites these days load their resources using different sites and servers, which makes the use of CORS important. CORS allows the servers to identify and separate the safe origins, who can have access to the server besides other elements of server connectivity.

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