postMessage debugger is a developer tools chrome extension. it's a free extension , it has 4,000+ active users since released its first version, it earns an average rating of 4.55 from 11 rated user, last update is 1987 days ago.
This chrome extension prints messages sent with postMessage to the console for debugging.
You could download the latest version crx file or older version files and install it.
English.
86% user give 5-star rating, 14% user give 4-star rating. Read reviews of postmessage debugger
You could find more help information from postmessage debugger support page.
You could send emails to publisher, or check publisher's website.
You could click to report abuse of postmessage debugger.
This extension is great! Use it a lot.
I was pleasantly surprised that this reports messages sent to iframes as well as messages received by the top frame as well. As others said, if you don't see anything in the devtools console, you probably need to pull out the sidebar to look at the verbose/debug log level. A good example case is the youtube embed API (you can find examples on codepen). It would be very helpful if this logged a bit more information about each MessageEvent rather than just the data...like the origin, source, ports and lastEventId. Currently it seems to log the window title, but perhaps the window url or origin would be more useful.
Very useful extension, but the thing about selecting 'verbose' in the Console's 'levels' box ought to be more prominent! It should be in the description of the Extension: "This extension prints messages sent with postMessage to the console (turn on Verbose levels to see them)"