postMessage-catcher

Name: postMessage-catcher
Rating: 3 (2 reviews)
Author: yangjin

A Chrome extension that captures the content of postMessage.

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postMessage-catcher is a Chrome extension designed to help developers capture the content of all messages posted and received via the postMessage API on the current webpage. It's an effective development tool that simplifies debugging tasks when working with communication between iframes.

With this extension, you can effortlessly monitor all message exchanges in real-time, offering clearer insights into iframe interactions and facilitating easier diagnosis of communication issues.

The project is open for contributions on GitHub, welcoming developers to enhance its functionality and usability.

Extension

By:

yangjin

Users:

970 17

Rating:

3.00

(2)

Version:

2.0.0 Last updated: 2025-04-30

Creation date:

2021-06-06

Risk:

Permissions:

storage

Size:

2.36M

Email:

ya*****@gmail.com

Full description:

Source:

Chrome Web Store

Updated:

20 hours ago

Ranking

# 30,628 ▲ 413

Other rankings

#1844 in Developer Tools ▲ 6

User reviews

Tried this in Jan 2023 to understand how the youtube javascript embed API interacts over postMessage. This extension doesn't catch or report any of the postMessages that may happen in sub-iframes (e.g. not in the top window). So if you prototype something in codepen or whatever you won't see the postMessages in this extension. It appears (limited testing) it only reports postMessages RECEIVED by the top window...so you don't even see postMessages sent by the top window to child iframes. This makes this extension pretty useless as you can add a single "message" listener that logs messages in the devtools console to accomplish the same thing.

Ma*****, 2023-01-20

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Extension safety

Risk impact

postMessage-catcher requires very minimum permissions.

Risk impact analysis details

High Injects scripts into web pages, which may alter or extract site contents, resulting in a substantial risk.

Risk likelihood

postMessage-catcher has earned a fairly good reputation and likely can be trusted.

Risk likelihood analysis details

High This extension has low user count. Unpopular extensions may not be stable or safe.
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