Description

Contractors take thousands of photos and lose most of them. They sit in a camera roll, unsorted, until somebody needs one for a dispute and cannot find it. Trace is the layer that fixes that: crews photograph the work, photos file themselves to the right job by GPS, and the office turns them into branded reports a client can open without an account.

The device is authoritative until the server says otherwise. The file is written to the phone and a row to its own database before any network call is attempted.
Uploads are idempotent. Every capture carries an identifier generated at the shutter and sent unchanged on every retry. A response lost on a dying connection costs a retry, never a duplicate.
Nothing fails silently. Failures stay visible and retryable, and the office sees which phones are still holding photos.