AmiSync

A Syncthing-compatible file synchronization daemon for AmigaOS 3.x (68020 and up).

Syncthing keeps folders in sync between two or more computers: save, change or delete a file on one machine and the same thing happens on the others, over an encrypted connection, with no cloud account in the middle. It runs on Windows, macOS, Linux and phones.

AmiSync brings this to the classic Amiga. It speaks Syncthing's native protocol (the Block Exchange Protocol over TLS 1.3, via AmiSSL), so the Amiga appears as just another device in your Syncthing setup, and a folder on the Amiga stays mirrored with a folder on any of your other machines.

AmiSync is an independent project, not affiliated with or endorsed by Syncthing.

The status window: this device, the shared folders and the remote devices, each with its live state. Selecting a row expands it — here the amisync folder, showing what it holds and when it was last scanned.

AmiSync on Workbench 3.2 — the AppIcon's label is the live sync status. Double-click the icon to open the window above.

AmiSync's commands in Workbench's Tools menu.

Contents

• Status
• Features
• Requirements
• Installing
• First-time setup
• Running
• Building from source
• Third-party content
• Credits
• License

Status

AmiSync syncs files both ways with current Syncthing (v2.x): TLS 1.3 connections (dialling out or accepting inbound), deletions, directories, .stignore, per-block SHA-256 verification, conflict copies, rename/copy detection, local discovery, LZ4 message compression, and a persistent per-folder index that survives restarts without re-hashing.

Limits: a folder tree nests at most 12 levels deep; entries deeper than that are skipped. There is no fixed cap on the number of entries — the per-folder index grows as needed, so folder size is bounded by RAM.

Not supported: global discovery and relays (peers must be directly reachable — same LAN or a dialable address), symlinks, receive-encrypted/untrusted peers, and per-device folder sharing — every configured folder is offered to every configured peer.

A note on receive-only folders

A receiveonly folder is a mirror, and it is worth knowing exactly what that means before you put one somewhere you work:

• Files you create there stay there. AmiSync never announces them and never removes them.
• Files that arrived from the peer are the peer's. If you edit one, the peer's copy replaces your edit at the next scan — that is what keeps a mirror a mirror, since this mode has no way to send your change back.

Your edit is not thrown away: the copy being replaced is moved to the folder's .stversions drawer first, whether or not versioning is turned on, and the log says so by name. Copy it back out if you wanted it.

If you intend to edit files in a folder, use sendreceive instead.

Features

• Send-receive, send-only and receive-only folders, synced with ordinary Syncthing peers over BEP / TLS 1.3 (AmiSSL), with the connection pinned to the configured device ID
• Persistent per-folder block index: a restart re-uses stored hashes instead of re-reading every file
• Near-instant pickup of local changes: filesystem notification triggers a scan seconds after a drawer changes, with a periodic scan as the backstop (it catches in-place edits, which change no drawer, and filesystems without notification support)
• .stignore patterns, Syncthing-style conflict copies, and rename/copy detection (content already present locally is copied on disk instead of re-downloaded)
• Optional file versioning (versioning = yes): a file a remote change would overwrite or delete is first moved to a .stversions drawer, so a mistaken delete elsewhere is recoverable (Syncthing's "trash can" mode)
• Local peer discovery and runtime peer adding, from the status window's Remote Devices list or via ARexx ADDPEER
• Workbench integration: a status AppIcon on the backdrop, daemon commands in the Tools menu, and the live status in ENV:amisync/status
• Scriptable control via an ARexx port (AMISYNC)

Requirements

• AmigaOS 3.x on a 68020 or better, no FPU needed; expect slower TLS handshakes below a 68040
• AmiSSL 5.x installed
• A running TCP/IP stack providing bsdsocket.library (Roadshow, AmiTCP or Miami)
• About 4 MB is the working minimum for one folder and a peer or two.

Installing

Download the latest amisync-<version>.lha from the Releases page and extract it on the Amiga, then double-click Install. From a Shell, Installer Install does the same.

The installer picks the build for your CPU, copies amisync and amisync-genid into your command path (default C:), installs the Workbench icon, seeds S:amisync.conf (an existing config is left untouched), creates this device's identity if AmiSSL is installed and none exists yet, and can add AmiSync to S:User-Startup so it starts at every boot.

Prefer to compile it yourself? See BUILDING.md.

First-time setup

These steps use the status window, and work for a peer on the same LAN. One anywhere else has to be added in the config file — see below.

1. Start AmiSync — or just reboot, if the installer added it to User-Startup. An AmiSync AppIcon appears on the Workbench backdrop; double-click it to open the status window.

2. In Syncthing, add the Amiga and share a folder with it. On the same LAN the Amiga now appears in Syncthing's "Add Remote Device" suggestions, pick it, then share a folder with it.

   If you need the full device ID run amisync-genid SHOWID.

3. Back on the Amiga, add the Syncthing device. On the same LAN it appears in the status window's Remote Devices list as Discovered. Select it and press Add...

   AmiSync only ever connects to peers you add — nothing is accepted automatically, and the device ID pins the TLS connection, so a peer presenting any other certificate is rejected.

4. Accept the folder it shares. Once that peer connects, the folder appears in the Folders list as Offered. Select it and press Accept..., then choose or name the drawer to keep it in.

Syncing starts as soon as the folder is accepted.

Every folder is offered to every peer. Unlike Syncthing, AmiSync has no per-device folder sharing: a device you add can request any file in any configured folder. Add only devices you would give all of those folders to, and keep anything you would not on a separate machine.

Peers that aren't on the LAN

Discovery only reaches the local network, so a peer anywhere else has to be given an address. That is done in S:amisync.conf:

; the other device's Syncthing ID and address:
peer = P56IOI7-MZJNU2Y-IQGDREY-DM2MGTI-MGL3BXN-PQ6W5BM-TBBZ4TJ-XZWICQ2 192.168.1.50:22000

; folder id (must match the id in Syncthing), local path, mode:
folder = amisync Work:Sync sendreceive

Copy the folder id from its settings in Syncthing. ARexx ADDPEER and ADDFOLDER do the same at runtime and persist it.

config/amisync.conf.example documents every option.

Running

amisync                  # starts and detaches into the background
amisync NODETACH         # stay in the foreground

Workbench

While running, AmiSync shows an AppIcon on the Workbench backdrop whose label is the live sync status ("Up to Date", "Syncing (3 files)", "Offline") — double-click it for a live status window where folders and devices can be added, opened, rescanned, paused and removed, with per-folder and per-device sync state (the AmigaGuide manual has the full tour). Its commands also appear in Workbench's Tools menu. Set appicon = no to turn off both the icon and the menu.

ARexx control

Everything can also be scripted through an ARexx port named AMISYNC:

Command	Effect
STATUS	returns a sectioned report (this device: uptime + traffic totals; folders: files/size + last scan; remote devices: state, identity, traffic) in RESULT
DISCOVERED	returns the unconfigured devices seen on the LAN via local discovery (device ID + address), for review; amisync never connects to them on its own
ADDPEER <id> [host[:port]]	add a device as a sync peer at runtime and append a peer line to S:amisync.conf. With a host it is dialled right away; with the ID alone it waits to be found by local discovery
ADDFOLDER <id> <path> [mode]	add a folder at runtime and append its config line — the drawer is created if needed, scanned, then offered to every configured peer; mode is sendreceive (default), sendonly or receiveonly
REMOVEFOLDER <id>	stop syncing a folder and remove its config line — local files stay, peers keep their copies
RESCAN	re-scan all folders now and announce any local changes (normally automatic: filesystem notification within seconds, plus a periodic ~60 s scan)
PAUSE [id]	stop dialling all peers, or just one — id must be the peer's full device ID, not the short prefix STATUS shows
RESUME [id]	resume dialling all peers, or just the one device id (full ID, as above)
LOGLEVEL [debug|info|warn|error]	set the log verbosity, or return the current level with no argument
VERSION	returns the version string
HELP	returns the command list
QUIT	stop the daemon cleanly

On the Amiga itself, the installed amisync.guide (an AmigaGuide manual) covers all of the above in native hypertext — open it with MultiView, or from a Shell with MultiView C:amisync.guide.

Building from source

See BUILDING.md for the cross-compilation toolchain, build targets, tests and packaging.

Third-party content

AmiSync is MIT licensed (see LICENSE). Two things in this repository are not, and keep the licences their authors gave them: the vendored LZ4 compressor (BSD 2-Clause) and the Syncthing logo together with the Amiga icons converted from it (MPL-2.0). Every affected file is listed in THIRD-PARTY.md.

Syncthing is a trademark of the Syncthing Foundation. AmiSync is an independent project, not affiliated with or endorsed by Syncthing.

Credits

Developed with assistance from Claude (Anthropic)

Tested using amimcp (Thomas Luebker)

License

MIT — see LICENSE. Copyright (c) 2026 Thomas Severinsen

The third-party content listed above keeps its own licenses.