Location Tax Tracker

TaxTrack builds a private, time-stamped record of where you have been —
so you can defend your tax-residency status with evidence, not memory.

Designed for Puerto Rico Act 60 residents, California non-residents
under FTB §17014 audit risk, and anyone tracking IRS Substantial
Presence Test thresholds, TaxTrack captures your location every six
hours, classifies each capture against bundled jurisdiction polygons
offline, and hash-chains the result so the record can be verified later.

EVIDENCE SOURCES
• Six-hour location captures on UTC boundaries
• Photo metadata import (GPS + timestamps; pixels never read)
• Flight events synced from the Flighty calendar
• Manual corroboration notes for unverified days

OFFLINE JURISDICTION CLASSIFICATION
TaxTrack ships with Natural Earth admin-0 and admin-1 polygon data and
the evansiroky timezone-boundary dataset. Every capture is classified
without a network call. We never use Apple's online geocoder for
classification — only for human-readable address hints.

HASH CHAIN INTEGRITY
Each capture is SHA-256 hashed into a chain against the prior record.
Tampering, reordering, or deletion is detectable. The chain is mirrored
to your iCloud private database and verifiable from the app or from
exported data.

CALENDAR-AWARE FLIGHT EVIDENCE
TaxTrack reads calendar events synced by Flighty (only those — every
other event is ignored), extracts departure and arrival airports,
classifies each endpoint, and optionally fills inferred gap days
between flights with an audit-readable "inferred" flag. Calendar
events are never modified.

EXPORT FOR AUDIT
Settings → Export package produces a folder containing CSV, JSON, a
human-readable hash chain, and a monthly-map PDF. AirDrop it to your
accountant, your attorney, or an auditor.

THREE-YEAR PR ROLLING COUNTER
The app tracks year-to-date Puerto Rico day counts and the three-year
rolling total used in the Substantial Presence Test, plus California
day counts and the §1.937 30-day international allowance.

PRIVACY-FIRST
TaxTrack has no server. Your data lives on your device and (optionally)
in your own iCloud private database that only you can access. No
analytics, no telemetry, no third-party SDKs, no ads. Photo pixels are
never read.

WHAT THIS APP IS NOT
TaxTrack is not legal or tax advice. The records it produces are
supporting material. Talk to a licensed attorney or CPA for any
residency question. The app is a personal-use audit-trail tool.

REQUIREMENTS
• iOS 17 or later
• "Always" location access for background captures
• Optional: iCloud sync, photo library access, calendar access
• Optional: Sign in with Apple (for multi-device sync identity)