ChronoShift

ChronoShift builds a light, dark, sleep, melatonin and caffeine plan for your flight — for every member of the family, including children.

Free — every trip, the whole family. No account, no subscription, no ads, no server. Everything stays on your phone. If it helped you, you can leave a voluntary tip in sats over Lightning; it unlocks nothing.

What it does

• Flight number → route, time zones and estimated duration (no API key, no signup)
• Day-by-day plan: when to seek light, when to avoid it, when to sleep, when to nap
• Melatonin 0.5 mg timed to your chronotype — adults only
• Caffeine cutoff timed to your bedtime
• Family mode: adult, child and toddler profiles with shared light windows
• Chronotype test: five questions, a continuous 16–86 score (Horne–Östberg) instead of three boxes — it shifts your light window and melatonin timing
• Quick Turnaround: on a short trip it tells you not to shift at all
• Fixed blocks (work, school) — the plan avoids them and says what it costs
• Sleep diary: record the times you actually fell asleep and woke, and export the whole log as CSV
• Export the whole plan as .ics with alarms

What it is not

• Not medical advice. Melatonin is not for children or pregnancy without a doctor.
• The model is a simplification of the light phase-response curve, not individual calibration.
• Children's plans are routine-based, not clinically validated.
• We do not quote effectiveness percentages. We have no data for them.

Privacy No account, no analytics, no server. Plans are stored in your browser/app storage. Optional PIN + fingerprint lock. The app talks to three addresses only: flight lookup, a BTC rate feed and the Lightning server for voluntary tips. A tip carries only a random order code.

Multilingual: English, Slovak, German, Spanish and Chinese.