Reference for http://www.bungie.net/Platform/Destiny2/Actions/Items/InsertSocketPlugFree/

Insert a 'free' plug into an item's socket. This does not require 'Advanced Write Action' authorization and is available to 3rd-party apps, but will only work on 'free and reversible' socket actions (Perks, Armor Mods, Shaders, Ornaments, etc.). You must have a valid Destiny Account, and the character must either be in a social space, in orbit, or offline.

Url: http://www.bungie.net/Platform/Destiny2/Actions/Items/InsertSocketPlugFree/

HTTP Method: POST

Requires Sign-in: true

Url Parameters: No Url Parameter documentation is available for this method.

Request/Response Body Formats:

Message Direction	Format	Body
Request	JSON	JSON object
Response	JSON	JSON object

The following is an example of a request JSON body for this method.

{
  "plug": null,
  "itemId": "0",
  "characterId": "0",
  "membershipType": 0
}

The following is an example of a response JSON body for this method.

{
  "Response": null,
  "ErrorCode": 0,
  "ThrottleSeconds": 0,
  "ErrorStatus": null,
  "Message": null,
  "MessageData": null,
  "DetailedErrorTrace": null
}