Programming Tutorials

  If you are developing a Chrome Extension using Manifest V3, you have almost certainly encountered this error in your extension management console: Unchecked runtime.lastError: The message port closed before a response was received. This error is frustrating because it often occurs silently in the background, causing your popup or content script to hang indefinitely while waiting for a response that never comes. It usually happens when you try to perform an asynchronous operation (like a  fetch  request or database lookup) inside the  chrome.runtime.onMessage  listener. Here is the root cause analysis, the technical breakdown of the message channel lifecycle, and the robust solution to fix it permanently. The Root Cause: Synchronous Expectations in an Async World To understand the error, you must understand how the Chrome Messaging API manages memory and resources. When a message is sent via  chrome.runtime.sendMessage , Chrome opens a communication port. ...