Cross Cloud Sync

Cross-Cloud Sync

Cloud Drive Sync can relay files between different cloud providers without any intermediate server. The trick is simple: point two sync pairs at the same local folder — one in download_only mode, one in upload_only mode.

How It Works

Source Cloud  ──download_only──▶  ~/cloud-bridge  ──upload_only──▶  Destination Cloud

The local folder acts as a bridge. The daemon continuously:

1. Downloads new/changed files from the source provider into ~/cloud-bridge
2. Detects those changes via the filesystem watcher
3. Uploads them to the destination provider

No file ever leaves your machine unencrypted — the data path is always Source Cloud → your disk → Destination Cloud.

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Confirmed Working: Google Drive → Nextcloud

This is an actively used production scenario. Files download from Google Drive and upload to Nextcloud automatically.

CLI setup

# 1. Add both accounts
cloud-drive-sync account add --provider gdrive
cloud-drive-sync account add --provider nextcloud --server https://your.nextcloud.com

# 2. Create a dedicated bridge folder (must exist before adding pairs)
mkdir -p ~/cloud-bridge

# 3. Download-only pair from Google Drive
cloud-drive-sync pair add \
  --local ~/cloud-bridge \
  --remote root \
  --account user@gmail.com \
  --provider gdrive \
  --mode download_only

# 4. Upload-only pair to Nextcloud
cloud-drive-sync pair add \
  --local ~/cloud-bridge \
  --remote /Documents/cloud-bridge \
  --account user@gmail.com \
  --provider nextcloud \
  --mode upload_only

Same email on both accounts? That's fine — accounts are identified by provider:email, so gdrive:user@gmail.com and nextcloud:user@gmail.com are completely separate entries.

Equivalent config.toml

[[accounts]]
email = "user@gmail.com"
provider = "gdrive"

[[accounts]]
email = "user@gmail.com"
provider = "nextcloud"
server_url = "https://your.nextcloud.com"

[[sync.pairs]]
local_path = "/home/user/cloud-bridge"
remote_folder_id = "root"
sync_mode = "download_only"      # Google Drive → local
account_id = "user@gmail.com"
provider = "gdrive"

[[sync.pairs]]
local_path = "/home/user/cloud-bridge"
remote_folder_id = "/Documents/cloud-bridge"
sync_mode = "upload_only"        # local → Nextcloud
account_id = "user@gmail.com"
provider = "nextcloud"

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Other Combinations

Example: Google Drive → Dropbox

cloud-drive-sync account add --provider gdrive
cloud-drive-sync account add --provider dropbox

mkdir -p ~/cloud-bridge

cloud-drive-sync pair add \
  --local ~/cloud-bridge \
  --remote root \
  --account user@gmail.com \
  --provider gdrive \
  --mode download_only

cloud-drive-sync pair add \
  --local ~/cloud-bridge \
  --remote "" \
  --account user@dropbox.com \
  --provider dropbox \
  --mode upload_only

Combinations table

Source	Destination	Status
Google Drive	Nextcloud	✅ Confirmed working
Google Drive	Dropbox	🧪 Untested — please report
Google Drive	OneDrive	🧪 Untested — please report
Google Drive	Box	🧪 Untested — please report
Nextcloud	Google Drive	🧪 Untested — please report
Dropbox	Google Drive	🧪 Untested — please report
Any	Any	🧪 Follow the pattern above

If you try a combination and it works (or breaks), please open an issue — your report helps everyone.

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Bidirectional Cross-Cloud

To mirror changes in both directions (edits on either side propagate to the other), use two_way for both pairs:

[[sync.pairs]]
local_path = "/home/user/cloud-bridge"
remote_folder_id = "root"
sync_mode = "two_way"
account_id = "user@gmail.com"
provider = "gdrive"

[[sync.pairs]]
local_path = "/home/user/cloud-bridge"
remote_folder_id = "/Documents/cloud-bridge"
sync_mode = "two_way"
account_id = "user@gmail.com"
provider = "nextcloud"

Warning: If both providers modify the same file at nearly the same time, a sync loop can occur — the daemon detects the conflict and applies the configured conflict strategy (keep_both, newest_wins, or ask). For high-churn folders, newest_wins is usually the most predictable choice.

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Tips

• Use a dedicated bridge folder. Do not reuse an existing personal folder — any file already in that folder will be uploaded to the destination provider on first sync.

• The bridge folder must exist before you add sync pairs pointing to it. The daemon will not create it automatically.

• Filter file types you don't want to relay by adding ignore_patterns to one or both pairs:

  [[sync.pairs]]
  local_path = "/home/user/cloud-bridge"
  ignore_patterns = ["*.gdoc", "*.gsheet", "*.gslide", "*.tmp"]

• Google Docs are exported as .docx/.xlsx/.pptx locally by default. These exported files will be uploaded to the destination provider. If you only want native Google format on the source side, add those extensions to ignore_patterns on the upload pair.

• Monitor the activity log after first setup to confirm files are flowing as expected:

  cloud-drive-sync activity --limit 50