Comparison

Undercurrent vs Flarely

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Undercurrent

Features
Read full description

You know something is off, but what? Headaches that seem random. Energy that crashes for no reason. You suspect a pattern, but every time the doctor asks "have you noticed any patterns?" you draw a blank. Undercurrent is a private notebook for the small things, and the patterns hiding inside them. LOG IN FOUR TAPS OR FEWER Symptoms, food, medications, activities, and observations. Quick chips for what you log most. Or just tell the on-device AI assistant in plain language: "headache after lunch" and it handles the rest. WHAT WE'VE NOTICED Once you've logged a few events, the Insights page surfaces co-occurrences in your own data, phrased in soft language. None of it claims to cause anything. You decide if it's signal or noise. • Pre-window pattern: what tends to show up in the hours before symptoms • Time-of-day cluster: when symptoms tend to gather • Day-of-week peak: which days run hottest • Recurring sequence: a familiar arc, repeated • Co-occurrence: tags that appear alongside symptoms • Seasonality: a year, at a glance (Pro) • Environment: weather, pressure, humidity, air quality (Pro) • Long-term cycles and intervention effectiveness (Pro) 100% PRIVATE BY DEFAULT • No account required, start logging immediately • All data stored locally on your device • AI runs on-device using Apple Intelligence; nothing is sent to a server to be analysed • Optional iCloud backup, protected by Apple's encryption • No analytics, no tracking, no ads A REPORT YOU CAN HAND TO YOUR CLINICIAN (Pro) One tap exports an editorial PDF: auto-numbered observations, frequency tables, time-of-day distributions, and an event log. Black-and-white printable, sized for a five-minute appointment. No portal login on the other end. APPLE HEALTH INTEGRATION (Pro) Pull in workouts and mindful sessions automatically. The data stays on your device and is folded into the same patterns engine. TRACK MULTIPLE PEOPLE (Pro) Separate threads for yourself, your kids, or anyone you care for. Each thread gets its own timeline, observations, and reports. BUILT ON PUBLISHED RESEARCH Self-monitoring is the most effective technique in digital health interventions for chronic conditions, backed by analysis of 85 clinical studies. Smartphone diaries have been shown to identify real triggers; visual diary summaries help patients and providers focus on actionable plans. FREE FOREVER • Unlimited logging of symptoms, food, meds, actions, observations • Today, Timeline, and Calendar views • AI chat assistant for plain-language logging • Basic Insights: pre-window, time-of-day, day-of-week, sequences, co-occurrences • Local-only data, stays on your device UNDERCURRENT PRO · ONE-TIME PURCHASE · $19.99 Pay once, keep everything forever. No subscription, no recurring charges. • Weather, pressure, and humidity correlations • Long-term cycles, seasonality, intervention effectiveness • Editorial PDF report for your clinician with full observation set • Track multiple people, with separate threads for each • Apple Health sync • iCloud backup Whether you're trying to figure out what shows up before your migraines, why your energy crashes after lunch, which foods leave you uncomfortable, or what helps your child sleep better, Undercurrent gives you a quiet place to write it down and the patterns that emerge over time. NOT A MEDICAL DEVICE Undercurrent describes statistical co-occurrences in your self-logged data. It is not intended to diagnose, treat, cure, or prevent any disease. Observations are informational only, not medical advice. Always consult a qualified healthcare professional about symptoms, medications, or treatment decisions. In an emergency, call your local emergency number. Notice what's quietly shaping how you feel.

About

Flarely

Features
Read full description

Flarely helps you track symptoms, food, and daily factors to uncover what triggers your flares, whether it's IBS, migraines, eczema, or any condition you define yourself. YOUR PERSONAL HEALTH DETECTIVE Log symptoms, meals, sleep, stress, weather, and medications. Flarely analyzes your data right on your device to find hidden correlations between what you eat, how you live, and how you feel. KEY FEATURES • Quick symptom logging with severity tracking (1-5 scale) • Food & drink diary with meal types and custom entries • Daily factor tracking: sleep, stress, weather, exercise, medications • Customizable tracking: add your own symptoms, triggers, and categories • Custom conditions: track any condition you want, not just preset ones • Personalized display: choose themes, layouts, and preferences to suit your workflow • Pattern analysis surfaces your personal triggers from your own data • Calendar heatmap to visualize flare patterns over time • Doctor-ready PDF reports to share with your healthcare team • Unlimited condition support: IBS, Migraine, Eczema, or anything you create • Beautiful light and dark mode PRIVACY FIRST All your data stays on your device. No account required. No servers. No tracking. Your health data is yours alone. FLARELY PREMIUM Unlock unlimited conditions, full pattern insights, flare warnings, comprehensive reports, and CSV export. Start understanding your body today. Privacy Policy: https://flarely.me/privacy/ Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

Undercurrent4 screens
Flarely4 screens

Verdict

The call

Undercurrent and Flarely are too close to call on the numbers: across 6 compared parameters — price, update cadence, ads and in-app purchases among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Undercurrent sells 1 one-off in-app purchase and Flarely sells 3 in-app purchases, starting at $4.99 per month. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

Undercurrent ships an update monthly, Flarely every 3 weeks. Both last shipped on October 6, 2026.

ScorecardNo meaningful differences
Undercurrent versus Flarely: the parameters behind the verdict, then further details
ParameterUndercurrentFlarely
PriceFreeFree
Update frequencyMonthlyEvery 3 weeks — better
AdsNoNo
In-app purchasesYesYes
DevicesiPhoneiPhone, iPod — better
Requires iOS16.415.1 — better
Further details — not scored
Size76 MB66 MB
Age rating12+4+
DeveloperLloyd RowatMouemen Derbass

In-app purchases

1 purchases

Undercurrent

One-time1
  • Undercurrent Health: Pro$19.99
3 purchases

Flarely

Subscriptions2
  • Flarely Premium$4.991 Month
  • Flarely Premium$29.991 Year
One-time1
  • Flarely Premium Lifetime$79.99

Questions

Is Undercurrent free?
Undercurrent is free to download, with in-app purchases available.
Is Flarely free?
Flarely is free to download, with in-app purchases available.
Do Undercurrent or Flarely have ads?
Neither Undercurrent nor Flarely shows ads.
Which is updated more often, Undercurrent or Flarely?
Undercurrent ships an update monthly, and Flarely every 3 weeks. Most recently, Undercurrent was updated on October 6, 2026 and Flarely on October 6, 2026.

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