Private · Browser-based · Activity file diagnostics

FIT File Validator & Health Check

Inspect the binary structure and activity-level health of a FIT file. The report combines protocol checks with conservative record diagnostics and recovery estimates.

Drop your .FIT file here

Analysis runs locally in a Web Worker. Your workout file is not uploaded.

No upload No account Browser-only processing

activity.fit

Recovery confidence
Sport
Distance
Duration
Start

FIT health report

Activity stats

Average heart rate

Max heart rate

Average cadence

Average power

Private route map

Vector-only track visualization. No map tiles or GPS coordinates are requested from a third-party map service.

Recovery estimate

Repair & recovery options

Detected anomalies

Activity record sample

The interface downsamples very large activities for display. Repair logic works from the complete local file.

#TimeHRkm/hAltitudeCadencePower

What is validated?

The validator checks the .FIT signature, declared data size, optional header CRC, final file CRC, message definitions, parse completion, activity records, session/activity summaries and timestamp continuity. It also flags conservative sensor/GPS anomalies.

What the score means

The Health Score is a diagnostic aid, not an official Garmin compatibility certification. Some valid indoor activities have no GPS, and manufacturer-specific extensions may be ignored by the generic parser.

Analyzing FIT file…