Winter Arc Challenge: Oathline

Oathline is a winter arc challenge app that measures your days instead of handing you another checklist. Swear your oath, pick your rules, and watch your arc fill up day by day until December 31, or run a 30 day challenge, a 75 day challenge or a 90 day challenge.

MEASURED, NOT JUST TICKED
• Steps are counted by your phone's own step sensor. No account, no extra app, no watch needed.
• Water, reading and training take one tap: +1 glass, +5 pages, +30 min.
• Early rise gets a real timestamp. Tap "I'm up" and Oathline records the time. Late is late, honest beats perfect.
• Rules you can't measure, like no sugar or no social media, are a simple check at the end of the day.

YOUR ARC
• Every day of your winter arc is one segment of a big arc on the start screen. Kept days glow orange.
• Day 23 of 78, your streak, days kept, and when your arc ends, all at a glance.
• Forgot to log last night? Catch up on yesterday the next morning.
• Winter over? Keep going: start in spring or summer and it becomes a Spring Arc or Summer Arc of 90 days, with your whole history.

SHARE YOUR ARC CARD
Every sealed day becomes a story-sized card with your real numbers: 8,412 steps, up at 5:52, 8 glasses of water. Post it, keep yourself accountable, bring a friend into the challenge.

PROGRESS PHOTOS THAT STAY YOURS
Take one photo a day. Photos are stored only on your phone and never uploaded. A backup file keeps your oath, history and photos together, so nothing gets lost when you switch phones.

FREE, WITH LIGHT ADS
• Winter arc (until December 31) and the 30 day challenge
• Up to 5 rules with measured steps, water, training, reading and wake-up time
• Your arc, streak, progress grid and daily Arc card
• Evening check: one message, only if something is still open, with exactly what is missing
• Progress photos and full backup

OATHLINE PRO
• No ads
• 75 and 90 day challenges and hard mode: miss one day and you start again at day 1
• Unlimited rules
• Trends: days kept per week, 30 days of steps, and your weakest rule
• Day 1 vs. now photo comparison
• Morning oath reminder and CSV export
Monthly or yearly. Cancel anytime in Google Play in two taps.

PRIVATE BY DESIGN
No account. The free version shows light ads from an ad partner, personalized only with your consent; Pro has no ads. Apart from that, only anonymous usage counters without a device ID. Your steps, rules and photos stay on your phone.

Oathline is a challenge and habit tracker. It is not medical advice. Step counts come from your phone's sensor and can differ from other devices.

Recent changes:
- Free with light ads; Pro is ad-free.
- Rating prompt only after a success moment, and only rarely.
- Small improvements and stability.