Instant File Upload To A Collaboration Service By Querying File Storage Systems That Are Both Internal And External To The Collaboration Service

Techniques are presented herein for receiving a hash value of a file computed by a collaboration client prior to the collaboration client uploading the file to a collaboration server in an attempt to share the file with another collaboration client. The collaboration server may query an internal file storage system of file hashes for a hash value of a previously uploaded file that matches the hash value of the file to be uploaded. In response to the collaboration server receiving a notification that a matching hash value was not found in the file storage system, the collaboration server queries a first connector service that is in communication with a first service that has access to at least a first file storage system that is external to the collaboration server. The collaboration server queries the first connector service with the hash value of the file to be uploaded.