Folder Types Explained

Every shared folder in Syncthing has a type that governs whether the local device can send changes, receive changes, or both. Choosing the wrong type is a common source of sync confusion.

Core Idea

The folder type is configured locally per-device. Two devices sharing the same Folder ID can have different types. A server set to Receive Only will never push local changes to peers.

The Four Folder Types

1. Send & Receive (Default)

This device both uploads local changes and downloads remote changes.

• Changes made locally propagate to all peers.
• Changes made on any peer propagate to this device.
• This is the standard bidirectional sync mode.

Best for: Most desktop and laptop use cases where you edit files on any device.

Node A (Send & Receive) <----> Node B (Send & Receive)
  Writes on A → B                Writes on B → A

2. Send Only

This device only pushes its local changes to peers. It never downloads changes from peers.

• If a peer modifies a file, this device ignores that change.
• If a peer deletes a file, this device does not delete it locally.
• The folder status will show "Out of Sync" if peers have changes this node hasn't applied — this is expected and intentional.

Best for:

• A master source device (e.g., a media server that should never be altered by remote changes).
• A build output folder that only pushes artifacts to nodes, never receiving anything back.

Node A (Send Only) ---push---> Node B (Send & Receive)
  Changes from B are ignored by A

3. Receive Only

This device only downloads changes from peers. It never pushes local changes to peers.

• You can modify files locally, but those changes never go to any peer.
• Local changes are stored but flagged internally. The folder shows as "Local Additions" or "Local Changes".
• You can revert local changes via Folder → Revert Local Changes in the GUI.

Best for:

• A read-only mirror or backup node (e.g., a NAS that should hold whatever the laptop has, but never push back).
• Nodes where you want to allow browsing and reading but not editing the shared dataset.

Node A (Send & Receive) ---push---> Node B (Receive Only)
  Changes from B are never pushed to A

4. Receive Encrypted

This device stores an encrypted copy of the folder data. It syncs the raw encrypted blobs but cannot read the contents. Used to implement untrusted cloud nodes — you can offload sync to a cheap VPS without that VPS being able to read your files.

• Requires setting an Encryption Password in the folder's sharing config.
• The node stores encrypted file content on disk.
• Only devices that know the encryption password can read the actual data.

Best for:

• Syncing through an untrusted relay node (cheap VPS, rented server) without exposing plaintext content.
• Combining Syncthing with cloud VPS hosting securely.

Node A (Send & Receive) ----encrypted only----> VPS (Receive Encrypted)
VPS cannot read content, just stores and relays encrypted blobs

warning

If you lose the encryption password for a Receive Encrypted node, that node's data is permanently unreadable. Store passwords in a secure credential manager.

Comparison Table

Type	Sends Changes	Receives Changes	Can Read Data
Send & Receive	✅	✅	✅
Send Only	✅	❌	✅
Receive Only	❌	✅	✅
Receive Encrypted	❌	✅ (encrypted)	❌

Real-World Architecture Example

A photo workflow with three nodes:

flowchart LR
  CAM[Camera/Import Laptop\nSend Only] --new photos--> NAS
  NAS[Home NAS\nSend & Receive] <-->|full sync| DESK[Desktop Workstation\nSend & Receive]
  NAS --encrypted blobs--> VPS[Offsite VPS\nReceive Encrypted]

1. The import laptop is Send Only — it only pushes new photos; edits on the NAS/Desktop never touch it.
2. The NAS and Desktop are Send & Receive — full bidirectional editing workflow.
3. The offsite VPS is Receive Encrypted — it holds a backup copy but sees only ciphertext.

Changing Folder Type

1. In the GUI, click the folder card to expand it.
2. Click Edit.
3. Under the General tab, change the Folder Type dropdown.
4. Click Save. Syncthing immediately applies the new behavior.

What's Next

• Device and Folder Management