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Export and import

Exporting

Settings → Utilities → Export writes your saved Grooves to a file you choose the folder for. The file is named metronomo-yyyy-mm-dd-hhmmss.json, stamped in UTC to the second so a folder of them sorts oldest to newest; if that name is somehow taken, the new file becomes metronomo-yyyy-mm-dd-hhmmss (2).json rather than overwriting the one already there.

The file holds your saved Groove library and nothing else. Preferences and whatever is currently loaded in the editor belong to the device, not the file.

The file is JSON

It is a plain UTF-8 JSON document, indented two spaces, and you can open it in any text editor. Nothing in it is encrypted, compressed, or encoded — a backup you cannot read is a backup you cannot check.

The top level is an object with five keys. grooves is shown empty here and detailed below; a real file with an empty grooves is rejected on import:

{
  "format": "metronomo.backup",
  "version": 1,
  "exportedAt": "2026-08-26T14:22:31.004Z",
  "appVersion": "1.0.0 (4)",
  "grooves": []
}

A Groove

Each entry in grooves is one saved Groove:

{
  "id": "mt1d6i07-4f2a91",
  "name": "Shuffle",
  "bpm": 96,
  "beats": 4,
  "accents": [
    "strong",
    "medium",
    "soft",
    "medium"
  ],
  "subdivision": 3,
  "subdivisionPatterns": {
    "3": [
      "mute",
      "tick",
      "soft"
    ],
    "4": [
      "mute",
      "tick",
      "strong",
      "tick"
    ]
  },
  "countIn": 4,
  "alarm": {
    "enabled": true,
    "seconds": 300
  },
  "pause": {
    "enabled": false
  },
  "createdAt": 1787220902311,
  "updatedAt": 1787752724902
}

An accent level — on a beat or a subdivision slot — is one of strong, medium, soft, tick, or mute. In a subdivisionPatterns entry, slot 0 is the beat’s own place in the grid and is always mute, because the beat sounds from accents instead.

Importing

Settings → Utilities → Import reads one file back. The picker accepts any file type, because file managers routinely report a .json as text/plain; the parser is the real gate on whether a file is one of Metronomo’s.

A file that parses opens a dialog with two modes, and the dialog counts up what each one would do before you commit to it:

• Merge adds the file’s Grooves to your library. Nothing you have already saved is changed or dropped.
• Replace discards your library and installs the file’s in its place. This cannot be undone.

Under either mode, the Groove you are working on is left alone and can still be saved afterward. So are your preferences and your analytics choice — importing a file from someone else’s device does not import their settings.

Names and ids

A backup is a restore, not a second opinion, so nothing already on the device is overwritten:

• An id the library already holds belongs to some other Groove. The incoming one is given a fresh id and its name becomes <name> (imported), and both survive.
• A name already taken gets a number: Shuffle arriving against a Shuffle becomes Shuffle (2), then Shuffle (3).

When the whole file is refused

Four conditions stop an import before anything is read. In each case nothing on the device changes:

The last one is a guard on Replace more than on Merge: replacing against a file with no Grooves in it is a wipe, and nothing further down could tell it from a restore.

What import repairs

Import reads the file it is given, whatever wrote it. A number outside its range is clamped; a number that is missing or unreadable takes the app’s default rather than the nearest bound, so a file with no countIn imports with a four-bar count in, not none, and one with no bpm imports at 120. An unrecognized accent level becomes medium, an accents array that does not match the beat count is trimmed or padded, and keys the app does not know are dropped rather than stored. A Groove that survives import is one the app could have created itself.

Four things are not repaired that way.

• A Groove with no usable name, or no usable beats, is skipped entirely.
• A subdivisionPatterns entry is kept only if it still describes its own count exactly. If the key is outside 1–8, if the array is not exactly that long, or if any level is unrecognized, that entry is dropped and the Groove imports with that count’s ticks undrawn. Every other count is repaired on its own, so one bad entry costs you only itself. Unlike accents, an entry is never trimmed or padded to fit. Slot 0 is the one exception: whatever it holds is pinned back to mute, since the beat sounds from accents. An entry that is only the default once that pin lands — every other slot at tick — is dropped too, because an undrawn pattern is no pattern.
• A file whose format is not metronomo.backup is not a backup at all, and nothing in it is read.
• An alarm or pause whose seconds is missing or unreadable is switched off, not set to a default. This is the one place the fallback goes to nothing rather than to the app’s own value, so a rule marked enabled with no usable seconds arrives off.