What is BorderSense?
BorderSense is an iOS, iPadOS, macOS, and Apple Vision app that tracks visa days across multiple countries and zones, with a focus on the Schengen 90/180 rolling calculation. It is built for digital nomads, expats, dual citizens, and frequent business travelers who hold one or more passports and need to know how many compliant days they have left in each zone. The app logs every border crossing, projects remaining days on a calendar, and warns before an overstay.
Why BorderSense works
Schengen, UK, US, Thailand, and similar visa rules use rolling windows that humans calculate wrong under stress, and an overstay can cost entry bans and fines. BorderSense uses the same calculation logic as the EU's official Schengen calculator, applies it across multiple passports and zones, and projects forward in time so a traveler can pick the right departure date instead of guessing at the gate.
BorderSense features
- Schengen 90/180 calculator. Applies the exact calculation method used by the EU's official immigration calculator so the day count a traveler sees matches what a border officer will see.
- Multi-zone tracking. Tracks visa allowances across Schengen, USA, UK, Thailand, Japan, UAE, and ECOWAS in a single trip log.
- Calendar projection. Shows visa status on any future date so travelers can pick departure days that keep them within their allowance.
- Multiple passport profiles. Lets dual citizens and families maintain separate stay counters per passport so each one stays compliant independently.
- Passport Control Mode. Strips the screen down to the minimum information needed at a border counter so officers see only stay totals.
- Offline operation and notifications. Works offline at land borders with patchy data and pushes early warnings as a traveler approaches a visa cap.
Who BorderSense is for
- Digital nomads slow-traveling in Europe who need to time exits from the Schengen zone without losing access to their preferred coworking cities.
- Frequent US business travelers in and out of the Schengen area who must keep cumulative days under 90 inside any 180-day window.
- Dual citizens carrying two passports who want each passport's stay count tracked separately to use the most advantageous one at each border.
- Long-term backpackers in Southeast Asia juggling visa runs across Thailand, Vietnam, and neighbors who need a single ledger of legal days.
Similar micro SaaS ideas you can build
- Tax residency day counter. App for cross-border consultants that logs physical presence days against country-specific tax residency thresholds and warns before triggering a new tax home, sold by annual subscription.
- Crew duty hours tracker. Tool for offshore and aviation crew that records on-site days against work permit and rest rules, used by HR to defend audits, billed per crew member.
- Au pair visa companion. Mobile app for au pairs and their host families that tracks J-1 and similar program day limits, paid by agencies that place candidates.
- Snowbird residency planner. App for retirees who split the year between Canada and the US that tracks days against the IRS substantial presence test and warns before tax residency flips.
