I made a Python script specifically for this purpose.
https://github.com/In-line/btrfs-diff
$ git clone https://github.com/yourusernameIn-line/btrfs-diff.git
$ cd btrfs-diff
$ chmod +x btrfs-diff
$ ./btrfs-diff --human /.snapshots/8/snapshot/ /.snapshots/9/snapshot/
{
"name": "/",
"total_size": "4.00 KB",
"subfolders": [
{
"name": "var",
"total_size": "4.00 KB",
"subfolders": [
{
"name": "log",
"total_size": "4.00 KB",
"files": {
"snapper.log": "4.00 KB"
}
}
]
}
]
}