How to Avoid CORS Issues when Calling Suitelet Endpoint for External Applications

Introduction: When developing applications that interact with Netsuite Suitelet endpoints from external sources, you may encounter Cross-Origin Resource Sharing (CORS) issues. CORS is a security mechanism implemented by web browsers to restrict cross-origin HTTP requests. By default, browsers enforce the same-origin policy, which prevents requests from different origins. However, you can overcome these CORS restrictions by using the “no-cors” method. In this article, we will explore how to avoid CORS issues when calling a Suitelet endpoint for external applications by utilizing the “no-cors” method.

Step 1: Understand CORS and Its Limitations: Before diving into the solution, it’s essential to understand CORS and its limitations. CORS is designed to protect users from malicious requests by restricting cross-origin requests. However, it can sometimes pose challenges when integrating external applications with Suitelet endpoints. The “no-cors” method is a way to bypass CORS restrictions, but it comes with limitations. With “no-cors,” the response from the server is not accessible, and certain headers may be restricted.

Step 2: Implementing the “no-cors” Method: To avoid CORS issues, you can utilize the “no-cors” method when making requests to Suitelet endpoints from external applications. The “no-cors” method allows the request to be made without triggering CORS checks by the browser. Here’s an example code snippet using JavaScript’s Fetch API:

fetch('https://your-suitelet-endpoint-url', {
  method: 'GET',
  mode: 'no-cors'
})
  .then(response => {
    // Handle the response
    // Please note that with "no-cors" mode, the response cannot be accessed directly
    // You can check the response status or perform any necessary actions
    console.log('Request sent successfully.');
  })
  .catch(error => {
    // Handle the error
    console.log('Error occurred:', error);
  });