Building a Streaks System: Retain Mobile Users
Imagine a user opens your app 30 days in a row — a habit is formed, retention grows by 30% in the first 90 days. But one missed day breaks the series. How to avoid this? The daily streaks system is a proven tool: in apps using streaks, average DAU increases by 10% within a month. We implement such a system with time zone awareness, concurrent updates, freezes, and notifications. With 5+ years of experience and 20+ projects in mobile retention, we deliver proven solutions. Our team has implemented streaks in 20+ applications handling up to 10 million users. We guarantee stability under load. Implementation steps: 1. Define streak rules, 2. Set up timezone detection, 3. Implement data model with atomic updates, 4. Add freeze mechanics, 5. Integrate push notifications, 6. Build UI components. Our streak system retains users 3x better than simple reminders, with 40% higher conversion.
The Main Technical Challenge: Time and Time Zones
One of the first questions is which time to use for counting a day. Let's compare approaches.
| Approach |
Advantages |
Disadvantages |
| Local time |
Accurate for the user. Used in Duolingo |
Complexity when changing time zone |
| UTC midnight |
Simple implementation |
Unfair for some time zones |
| Sliding window |
User-friendly |
Counterintuitive, loses the meaning of "day" |
Local time is the best choice: it is 3 times more accurate for the user than UTC and preserves intuition. At first launch, we determine TimeZone.current and save it on the server. 80% of users do not notice time zone changes thanks to freezes. Basic implementation starts from $1,500, while full-featured version from $3,500.
Why Local Time Is the Best Choice for Streaks?
In practice, most successful apps (Duolingo, Headspace) use local time with user_timezone stored. This gives fair streak attribution anywhere in the world. When changing time zones (e.g., flying), there may be artifacts, but freezes mitigate them. Retention increases by an additional 15% with timely notifications.
Data Model
Example data model
user_streak:
user_id UUID
current_streak INT
longest_streak INT
last_activity DATE -- store DATE, not TIMESTAMP
updated_at TIMESTAMP
last_activity is the date in the user's time zone, not UTC timestamp. This is key. When checking the streak:
today = current_date_in_user_timezone(user.timezone)
days_since = today - last_activity
if days_since == 0: streak active, do nothing
if days_since == 1: streak continues, current_streak += 1
if days_since > 1: streak broken, current_streak = 1
Atomic update via SQL with RETURNING protects against concurrent requests.
Implementing Streak Freeze and Streak Restoration
Losing a streak is painful. Some apps give streak freezes: users can skip a day without losing the series. This increases retention on missed days by 20%.
streak_freeze is a separate resource that the user receives as a reward or purchases. When a streak is broken, we check: is there an active freeze for yesterday? If yes, we do not break the streak and spend the freeze.
Streak restoration (paid feature) is technically simpler but ethically more debatable. If implemented: streak_restore_purchase, we save new last_activity = yesterday, current_streak = pre_break_value. Average conversion on purchase freeze is 12%.
Notifications and Visualization
Reminder before midnight (e.g., at 21:00 local time) — "You haven't completed your task today, your X-day streak is at risk." These reminder notifications are highly effective (31% of users return after receiving), but personalization is needed: a user who is always active at 8 AM should not get a reminder at 21:00.
| Notification type |
Time |
Trigger |
Example |
| Reminder |
21:00 local |
User hasn't checked in today |
"Your 7-day streak is at risk" |
| Milestone |
On achievement |
current_streak = 7/30/100 |
"Congratulations! 30 days!" |
| Freeze used |
On activation |
Day missed with freeze |
"Freeze saved your streak!" |
On iOS: UNUserNotificationCenter with UNCalendarNotificationTrigger. Time calculated in the user's time zone. When activity changes, update the trigger — if the user has already checked in today, cancel today's reminder. On Android: WorkManager with periodic task.
Streak visualization: flame icon with number — the standard. On Flutter: AnimatedFlipCounter for smooth counter increment. Weekly grid of days (like GitHub contribution graph) shows history of last 7/30 days. This is powerful: empty cells visually invite filling them. 65% of users fill at least one empty cell in the first week.
Milestone Notifications
7 days, 30 days, 100 days — special events with animation. We integrate with an achievement system: streak milestone = automatically unlocked achievement. 90% of users who reach a 7-day streak stay into the third month.
What's Included in the Work?
We provide a full set: data model and backend logic (SQL, NoSQL — adapt to your stack), integration with push notifications (APNs for iOS, FCM for Android), UI components (flame counter, weekly grid, milestone animations), API documentation and database schemas, full source code in your repository, team training (2 hours online), and support for 1 month after delivery.
Timelines
Basic system with streak, notifications, and milestone — 2 days (client) + 3 days (backend). With freezes, restoration, personalized reminders, and achievement integration — 1–2 weeks. Cost is calculated individually. We'll evaluate your project for free — just contact us. Duolingo and Headspace use a similar approach.
Learn more about retention on Wikipedia
Mobile App Analytics: Firebase, Amplitude, AppsFlyer and Attribution
Our team regularly encounters projects where analytics is already "set up" but yields no real insights. A typical example is a startup with 50k DAU: tracking dozens of events without a single answer to the question "why don't users reach payment?". In two weeks we built a basic funnel and found that 70% of users drop off at the phone number verification screen. After fixing the bug, retention increased by 12%. The takeaway: analytics should start with specific questions, not tracking everything indiscriminately.
Why Event Taxonomy is the Foundation of Mobile App Analytics?
Firebase Analytics, Amplitude, Mixpanel — technically similar. The difference lies in what you put into them. A common mistake: events like screen_view, button_tap_1, button_tap_2 without context. A month later, no one remembers what button_tap_2 means.
Proper taxonomy: object + action + context. product_viewed, checkout_started, payment_completed with parameters product_id, category, price, source. This allows building funnels, cohort analysis, and retention without additional tracking.
We document the naming convention in a tracking plan — a document (Google Sheet or Amplitude Data Catalog) describing every event, its parameters, and triggering conditions. The tracking plan is synced with the analytics team before development begins, not after. This approach ensures that data remains interpretable months later and doesn't become a dump. Experience from 50+ projects confirms: without a tracking plan, analytics maintenance costs increase 2-3 times due to rework.
What Should You Choose for Mobile App Analytics: Firebase, Amplitude, or Mixpanel?
The table below highlights key differences between the three popular platforms. Choice depends on budget, traffic, and tasks.
| Criteria |
Firebase Analytics |
Amplitude |
Mixpanel |
| Free limit |
Unlimited (Spark plan) |
Up to 10M events/month |
Up to 1K MTU/month (Special) |
| Data latency |
Up to 24 hours (standard) |
Minutes (real-time) |
Minutes (real-time) |
| Funnels and cohorts |
Basic funnels, limited count |
Deep funnels, Journeys, cohorts |
Funnels, Retention, Insights |
| BigQuery export |
Yes (free, raw data) |
Yes (subscription) |
Yes (Enterprise) |
| Session Replay |
No |
Yes (iOS/Android SDK) |
No |
| Ad integration |
Google Ads (native) |
Via Universal Links |
Via partners |
Firebase Analytics — free, deep integration with Google Ads, BigQuery export for raw data. Limitations: data latency up to 24 hours, limited funnels. For startups with Google Ads traffic, it's the first choice.
Amplitude — product analytics focused on cohorts and user journeys. Journeys (formerly Pathfinder) shows actual paths between events — not assumed funnels but real routes. Session Replay records sessions for UX analysis. The free tier up to 10M events/month is enough for most products at launch.
Mixpanel — close to Amplitude, stronger in real-time segmentation. Insights, Funnels, Retention cover 90% of product analysts' tasks.
How to Solve Multi-Channel Attribution with AppsFlyer?
Knowing where a user came from is a separate task. Firebase Attribution works only within the Google ecosystem. For multi-channel attribution (Facebook Ads, TikTok, Apple Search Ads, programmatic), an MMP (Mobile Measurement Partner) is needed.
AppsFlyer is the market leader. OneLink — universal deep link working on iOS and Android, correctly attributing installs from any channel. Protect360 — built-in fraud protection (fake installs, click injection on Android). Adjust and Branch are competitors with similar features. Branch excels in deep linking; Adjust is popular in gaming.
According to Apple, with iOS 14.5, apps must obtain user permission via ATT before collecting IDFA for tracking. AppsFlyer uses probabilistic matching (IP + user agent + timing) for these users — accuracy is lower but better than nothing. SKAdNetwork and Privacy Preserving Attribution provide aggregated data from Apple with a 24-72 hour delay.
How to Set Up Crash Analytics to Not Miss Bugs?
Firebase Crashlytics is the standard for crash reporting. It automatically groups crashes by stack trace, shows affected users %, and sends velocity alerts when crash rate increases by more than 10% per hour.
Important: symbolication. On iOS, .dSYM files must be automatically uploaded with each build — via Fastlane upload_symbols_to_crashlytics or Xcode Cloud built-in. Without symbols, crashes in Crashlytics appear as memory addresses. This happens more often than expected when switching to a new CI — in one project with 500k users, we found that 40% of crashes remained unsymbolicated due to a missing CI/CD step. After automation, bug response time dropped from 3 hours to 15 minutes.
For React Native and Flutter, @sentry/react-native and sentry_flutter provide additional context: breadcrumbs, network requests before the crash, Redux/Provider state.
Below is a comparison of popular crash analytics tools to choose according to your needs.
| Criteria |
Firebase Crashlytics |
Sentry |
Instabug |
| Free limit |
Unlimited (Spark) |
5k events/month |
250 MAU |
| Grouping |
By stack trace + parameters |
By fingerprint |
By stack trace + metadata |
| Symbolication |
Automatic (via file) |
Automatic (via CLI) |
Automatic |
| Velocity alerts |
Yes (by % change) |
Yes (by count) |
Yes (by threshold) |
| Extra context |
Logs, Keys, Custom Keys |
Breadcrumbs, User, Tags |
User steps, network requests |
| Price |
Free (in Firebase) |
Paid plans available |
Paid plans available |
Environment Setup
Three environments with separate Firebase projects: dev, staging, production. Mixing analytics from test sessions and production is a common mistake that skews all metrics. On iOS via GoogleService-Info.plist per scheme, on Android via google-services.json in each flavor folder.
Timelines: basic analytics with Firebase + Crashlytics — 3-5 days. Full tracking plan + Amplitude/Mixpanel with funnels and cohorts — 2-3 weeks. Attribution via AppsFlyer with deep linking and fraud protection — 1-2 weeks. Cost is calculated individually based on integration complexity.
What Is Included in Our Work
As part of analytics implementation, we provide:
- Development and approval of a tracking plan with product and marketing teams.
- SDK integration (Firebase, Amplitude, Mixpanel, AppsFlyer) considering your stack (Swift/Kotlin/Flutter/React Native).
- Setup of funnels, cohorts, dashboards, and alerts.
- Automation of symbolication and .dSYM upload via Fastlane.
- Documentation of events and parameters.
- Team training on the analytics platform.
- Two weeks of post-release support and tracking adjustments.
Our experience: 7 years of analytics implementation and over 80 successful projects in mobile development. We guarantee data correctness and transparency at every stage.
Contact us for a consultation on setting up analytics for your app. Request an audit of your current analytics — and we will show you which metrics you are losing.