Wonderful little addon!
Thank you very much!

Would be great, if one could have several of these buttons!

;-)

Works great, but for one critical flaw: One can define multiple commands, but only one displays in the toolbar :-(

Very nice!

Does the job. But if you pin a batch file it does not parse it correctly. In my example it skipped any more advanced programming arguments, and went straight to a timeout command within the batch. Compiling as an executable fixed this but I gotta -1 for this. Ill happily submit my batch code.

Also minus 1 for the client, connection check at the beginning, and vagueness surrounding this client. Is it always running as a service? Does it only open with Firefox?

Just want to pin a simple batch file! FF57 in case that matters.

With Firefox ESR v52.5.0 (64-bit) the right-click on the toolbar icon does not bring up a context menu to select the external application. You have to go to the Add-ons page to change this which is rather laborious. This is with the latest version 0.2.7 which claims to have fixed an ESR v52 bug, so looks like there are more.

Excellent replacement for the Open With extension - although I agree with the previous reviewer that there is no need to enforce the selection of an icon (which doesn't seem to be used anyway unless the "Toolbar button" option is used), and that there needs to be an easy way to re-order the list of applications (the only way atm seems to be to remove and re-add each entry in the desired order, which necessitates picking the icon again every time).

It works, but all this circus with 'mandatory(?) icons' linked to site, which gives 16x16 black-white .ico in size of 350KB(!) - a bit annoying.

I don't like that's necessary to add a icon
You are forced to have all the stuff under the External Application Button. Not having that context menu would save us a click.
You can't rearrange the list of applications.

To open twitch streams using streamlink, in the Executable field you paste the path to streamlink.
C:\Program Files (x86)\Streamlink\bin\streamlink.exe
In the arguments field: [HREF] Best if you want to open the streams at best quality, [HREF] 480p if you want to open streams in 480 and so on..

Excellent extension. It allowed me to replace the "Open with mpv" extension which was not E10s compatible and was a legacy app. Now with this WebExtension, I'm almost ready for Firefox 57.

click the add application button and nothing happens.
The chrome addon works well.

always told me select a placement for application , can not work. 55.0a1