MirrorFlow
Two-way folder sync that can tell your edit apart from the other side's.
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Preview
1 interface design, then a screenshot of it running. Drag, scroll or use the arrows.
Free while we’re in preview
Get MirrorFlow
Two-way folder sync that can tell your edit apart from the other side's.
The Mac button is for Apple Silicon. On an older Intel Mac, get this one instead.
One file, both ways. Double-click it for the window. Run the same file from a command prompt with arguments and it behaves as the command-line tool, because the engine is inside it. Nothing else to download and nothing to keep beside it.
Early preview. The window has been built and run, but not yet on a real Windows PC or Mac, so expect rough edges. The engine underneath it is fully tested.
- One file — no installer
- Runs on your machine, offline
- Source code published below
Free while in preview. It isn’t signed yet, so Windows or macOS will ask you to confirm the first time you open it. At launch, MirrorFlow is included in every plan along with the rest of the range.
Why there’s a baseline
A one-way mirror never has to think. It overwrites in the direction it was pointed. The moment you want changes flowing both ways, that’s how work gets lost.
MirrorFlow records a baseline at the end of each successful run. Next time it compares three things instead of two: side A, side B, and what the two last agreed on. That’s enough to separate “added on A” from “deleted on B”, and to catch the case that matters, where both sides changed the same file.
What happens to a conflict
Under the default manual policy, nothing happens. It reports the conflicts, refuses the whole run and exits 2, so you can’t end up half synced. newest, larger and keep-both resolve automatically, and even they won’t flip a coin: two conflicting versions with the same modification time under newest are left alone and reported.
Nothing is hard-deleted. Losing copies and propagated deletes are moved into .mirrorflow-trash/ inside that side’s root. Emptying it is your decision.
Limits worth knowing
Both sides are ordinary local paths. No SSH, no S3, no cloud endpoints. A changed file is copied whole, so editing one byte of a 4 GB video copies 4 GB. And it runs when you run it; there’s no watcher and no scheduler.
Reading on the job itself
- How to keep two folders in sync without losing anything Decide first whether one side is authoritative. If it is, mirror one way and think hard before enabling del...
Advanced & technical details Command-line builds, source code, checksums and a recorded session — for developers and IT teams
A working CLI prototype of true two-way sync: a persistent baseline lets it tell “you changed it” from “they changed it”, so one-sided edits propagate in the right direction and genuine both-sides edits are flagged as conflicts instead of being silently overwritten. By default it refuses the whole run rather than pick a side — verified that both versions survive untouched — with newest/larger/keep-both available when you want it decided. Deletes go to a trash directory, never unlink.
Recorded session
Naming status
Working name only — brand verdict **AVOID** (Very High). Collision: MirrorFlow. Rename completely.
What it draws on
Existing paid software whose best ideas shaped this program: GoodSync, Syncovery, SyncBackPro, ViceVersa Pro.
Command line
There is nothing extra to install. The program you download is the command-line tool as well: give it arguments instead of double-clicking it and it runs as one, with its output on your terminal. The standalone builds below are the same engine on its own, for machines where you would rather not ship a window at all.
mirrorflow 1.0.0 - two-way folder sync with real conflict detection
Techlosoft Sync Reliability Suite (Pro)
USAGE
mirrorflow init <dirA> <dirB> --state <state.json>
mirrorflow status <dirA> <dirB> --state <state.json> [--json]
mirrorflow sync <dirA> <dirB> --state <state.json> [--policy P] [--apply] [--json]
mirrorflow help | -h | --help
COMMANDS
init Record the current contents of both folders as the sync baseline.
Nothing is copied, moved or deleted.
status Read-only three-way comparison (A vs B vs baseline). No changes.
sync Propagate one-sided changes in the correct direction and handle
genuine conflicts according to --policy.
FLAGS
--state <file> Path to the persistent sync-state database (required).
--policy <name> Conflict resolution policy for "sync" (default: manual)
manual do not resolve; report and exit non-zero
newest the more recently modified side wins
larger the larger file wins
keep-both keep both, renaming the loser to
<name>.conflict-<side>-<timestamp><ext>
--apply Actually perform the changes. WITHOUT THIS FLAG MIRRORFLOW
IS A DRY RUN and writes nothing at all.
--json Emit a machine-readable JSON report on stdout.
HOW IT CLASSIFIES
Every file is compared by SHA-256 content hash on both sides and against the
hash recorded at the last successful sync, so a file whose mtime changed but
whose bytes did not is correctly reported as "unchanged".
unchanged identical on both sides
new-on-A/B added on one side since the baseline
changed-on-A/B modified on exactly one side
deleted-on-A/B removed on one side, untouched on the other
conflict both sides changed since the baseline, or one side deleted
a file the other side modified
...Recorded from the shipped binary, not written by hand.
Source
Every file the program is built from:
console.go · console_test.go · guided.go · main.go
SHA-256 checksums · build instructions & scope notes · full build plan