Multi-Platform Sync Without Duplicates: Best Config for Garmin + Strava + Intervals.icu

2026-05-06 · raymond

The short answer: The #1 headache for multi-platform users is seeing the same ride appear 3 times on Strava. The fix is correct sync topology: pick one "source of truth" platform and fan out from it (star topology), rather than connecting platforms to each other (mesh). GarSync's smart deduplication uses activity start timestamps to auto-skip duplicates — combine with the right topology and duplicates are gone.

Why Do Duplicates Happen?

The classic multi-platform headache: Garmin watch records a ride → Garmin auto-syncs to Strava (official integration) → you also have a GarSync task pushing Garmin to Strava → same ride appears twice. Add Intervals.icu pulling from both Garmin and Strava, and you've got 4 copies.

The root cause: messy sync topology — multiple data paths between platforms, so the same activity arrives at a target through different routes.

The Right Way: Star Topology

Core principle: pick one platform as your single source of truth. All sync tasks originate from this source and fan out to targets.

Recommended config (Garmin as source):

Garmin → Strava (disable Garmin's official auto-sync, use GarSync instead)
Garmin → Intervals.icu
Garmin → TrainingPeaks
Garmin → NAS backup

Each activity leaves Garmin once. GarSync's deduplication ensures it won't upload twice. Critical step: disable official auto-sync between platforms. If Garmin and Strava already sync via the official integration, don't create a second Garmin → Strava task in GarSync — choose one channel.

Avoid: Mesh Topology

This is a bad config:

Garmin → Strava ✅
Strava → Intervals.icu ✅
Intervals.icu → Garmin ← danger! Creates a loop

Once you have A→B→C→A, the same activity keeps circulating. GarSync's dedup catches most of it, but the cleanest solution is preventing the loop from the start.

How GarSync's Smart Dedup Works

GarSync generates a unique fingerprint for each activity: sport type + start timestamp (to the second). Before uploading to a target:

Check if the target already has an activity with the same fingerprint.
If yes → skip, no duplicate upload.
If the activity's updatedAt is newer than the target's version → update instead of creating a duplicate.

This means even if you have two sync tasks running, the same activity won't be uploaded twice.

Best Config for Common Setups

Setup 1: Garmin Watch User

Source = Garmin. Disable Garmin → Strava official sync. Create GarSync tasks: Garmin → Strava, Garmin → Intervals.icu, Garmin → NAS.

Setup 2: Multi-Device (Garmin Watch + Wahoo Bike Computer)

Consolidate both devices' data into Garmin (Garmin accepts third-party FIT files). Then use Garmin as the single source, fanning out to Strava and Intervals.icu.

Setup 3: Strava-Centric

If Strava is your primary social and analysis hub, you can use it as the source — but Strava doesn't store raw FIT files, so some data fields may degrade. We recommend using a platform that stores complete FIT files (like Garmin) as your source.

FAQ

Q: I already have duplicates — how do I clean them up?

A: GarSync won't delete data on your platforms. Manually remove duplicate entries on Strava or Garmin Connect. Then reconfigure your tasks to the star topology above — no new duplicates will appear.

Q: My bike computer and watch recorded the same ride — will it duplicate?

A: If both started at the exact same second, GarSync recognizes them as the same activity. But if you pressed start a few seconds apart on each device, GarSync will treat them as two separate activities.

Q: Can I use both Strava and Garmin as data sources?

A: Not recommended. If both sources push to the same targets while also syncing with each other, you risk creating loops. Always pick one platform as your single source of truth.