Meridian

The Challenge

Most tracking apps hand you isolated charts (a sleep line here, a mood line there) and leave you to compare them yourself. Meridian helps people see how the signals they record vary together while keeping those logs on their device.

Our Approach

Meridian is a quick daily check-in for sleep, energy, mood, focus, stress, headaches, digestion, and exercise. From your own history it builds a signal network and describes statistical associations between the signals you log. Your logs and the analysis stay on your device, with no account or login. Only Meridian Pro purchase validation and aggregate purchase analytics use a network service; they do not include your logs or analysis.

Key Features

• Quick daily check-in. Log the signals you enable with a short set of controls
• Signal network. See statistical associations in your own logs; an association does not prove cause and effect
• Next-day estimates. Meridian Pro shows estimates only when you have enough data and an estimate passes the app’s validation checks
• Calendar and trends. Browse your full calendar history, with 30-day trends for everyone and 60- and 90-calendar-day ranges in Pro
• JSON export. Meridian Pro creates a JSON file and opens the system share sheet; the app does not currently import exported files
• Private by design. No account, analytics, or ads; your logs and analysis stay on your device

Results

Meridian turns daily check-ins into a private view of recurring associations and trends in the signals you choose to log.

Common questions

Meridian, listed on the App Store as Mood, Sleep & Symptom Tracker, is an English-language iPhone and iPad app for logging daily mood and body signals and reviewing them over time. Every check-in records the same eight signals, mood, sleep, energy, focus, stress, headache, digestion and exercise, so days stay comparable, with optional reminders, a calendar and full history. On-device analysis aligns signals by calendar day and applies a permutation-based statistical screen before showing an association; an association is not proof of cause, and the app says so when history is limited. Logging, the calendar, history, 30-day trends and one association are free. A one-time Meridian Pro purchase, $9.99 in the US with no subscription, unlocks the full association network, next-day estimates that must beat a simple baseline on held-out earlier entries, 60- and 90-calendar-day trend ranges and JSON export. Entries and analysis stay on the device with no account, ads or tracking; RevenueCat handles only purchase validation and aggregate purchase analytics. Meridian does not diagnose conditions or replace medical advice.