Use curl

CAST Extend has a built in API that can be accessed in a manner of ways. It is therefore possible to download extensions using the API, for example with curl:

curl -# -O -J "<id>/[<version>]" -H "x-nuget-apikey: <my_api_key>" -H "accept: application/octet-stream"
curl option -#Displays a rudimentary progress bar to show download progress.
curl option -ODownloads the .nupkg file to the current folder using the file name specified on the Extend server. See
curl option -J

Tells the -O option to use the server-specified Content-Disposition filename instead of extracting a filename from the URL. See


Specify the ID of the extension you would like to download. The ID of an extension always takes the form com.castsoftware.<name>, without any version numbers. You can determine the ID of an extension using the CAST Extend website:

Specify the version number of the extension you would like to download. You can determine the ID of an extension using the CAST Extend website:

This option is not mandatory. When omitted, the most recent version of the extension you require will always be downloaded.
-H "x-nuget-apikey: <my_api_key>"

Sends your your unique API key as a header - this will grant you access without needing to authenticate. You can find your API key in your user profile in the CAST Extend website:

-H "accept: application/octet-stream"Tells the server (CAST Extend) that the client (curl) is able to accept a specific type of binary download.


Download the extension, version 1.1.1-funcrel:

curl -# -O -J "" -H "x-nuget-apikey: 57asdfs-bccb-44f380c1f905" -H "accept: application/octet-stream"

Download the lastest version of the extension:

curl -# -O -J "" -H "x-nuget-apikey: 57asdfs-bccb-44f380c1f905" -H "accept: application/octet-stream"

Download multiple extensions:

  • extension, version 1.1.1-funcrel
  • com.castsoftware.jee extension, latest version
curl -# -O -J "" -H "x-nuget-apikey: 57asdfs-bccb-44f380c1f905" -H "accept: application/octet-stream"
curl -# -O -J "" -H "x-nuget-apikey: 57asdfs-bccb-44f380c1f905" -H "accept: application/octet-stream"