CastSniffer – The Chromecast Broadcast Message Sniffer

CastSniffer is a chromecast sniffer. It connects to your chromecast and listens for broadcast messages. It’s capable of feeding back information on any broadcast messages the device sends. So when apps are launched it can give you detailed information about the apps. When it sees an app launched it connects and also echos any messages it broadcasts.

CastSniffer contains a simple method of sending chromecast receivers messages. Entering urn: followed by the namespace will set the namespace and typing a command followed by enter will send the command.

CastSniffer doesn’t require a development account, you can examine the behaviour of other apps or use it to debug your own.

CastSniffer is written in java so it should run on Windows, Mac, or Linux computers. First things first though, it runs in Java 1.8 – so if you don’t have it already or you’re not sure then:

Install the appropriate Java 1.8 for your computer from this link.

Great. Got that. Then save Cast Sniffer to your hard disk.

Get CastSniffer

To run CastSniffer you need to run it from the command line. The command is:

java -jar CastSniffer.jar [“Chromecast Name”]

e.g. if your Chromecast is called: My TV   then the command would be:

java -jar CastSniffer.jar “My TV”

CastSniffer must be started after your chromecast has been booted.

7 comments on “CastSniffer – The Chromecast Broadcast Message Sniffer”

  1. Motti says:

    hey im trying to access the program via cmd and im getting an error …
    Error: Unable to access jarfile CastSniffer.jar… what did i do wrong?

  2. C says:

    No docs about what you have discovered? no source ?

    1. Chris says:

      Hi. By the word “discovered” I presume you mean protocol/connection specs. No, I take the view that if Google wanted the information freely available then they’d have made it so. It would be lovely if they did so, but it’s not really my place to go doing that for them. The same with “source”.

  3. Fred says:

    Does not work with mine for some reason. firm ver :22062. I enter the correct cast name. Then nothing happen no error or connection . Only this:

    A Chromecast broadcast sniffer by Chris Ridings


    1. Chris says:

      It’s basically waiting to discover the device details. If it’s hung there then it’s not getting them for some reason. The devices need to be on the same network. If they are then a couple of people using Piccastr (elsewhere on my site) have a similar problem. I think it’s either a third party bit of software (firewall) causing it or it might be to do with multiple network cards on the computer (e.g. wireless and wired. You can try disabling all but the wireless test).

      If you can’t get it working, I’ll hopefully be looking at this again soon and producing an updated version. I now have code that won’t need java – which I suspect will help a lot!

  4. Fred says:

    I disable other network card even if they were not connecting to any network. Working now.
    Thanks for the infos.

    1. Chris says:

      Awesome. thanks for the feedback/confirmation.

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