You launch a corporate poll for 10,000 employees, and within a minute the server crashes under load. Or the results show 120% votes — someone rigged it. Sound familiar? We solve these problems every day. We develop mobile voting apps turnkey, from simple polls to complex systems with anonymity and real-time analytics. If you need a reliable solution for gathering opinions, contact us and we'll select the optimal stack. Our track record: 50+ voting projects, some serving up to 100,000 users.
A typical mobile voting form hides serious technical challenges: vote idempotency, double-tap protection, network loss handling, and result synchronization for thousands of concurrent participants. And that's just the beginning.
How to Protect Voting from Rigging?
The most critical part is ensuring each user votes only once. On the server, we use a unique constraint (poll_id, user_id) in PostgreSQL — the only reliable defense against duplicates under parallel requests. On the client, we add optimistic UI: immediately show the selection, disable retap, and queue the request on network errors with exponential backoff.
How to Implement Idempotency on the Server
To avoid duplicate votes even on network failures, use a unique database index and client-side checks. Step by step:
- Create a
votes table with unique constraint (poll_id, user_id).
- On the client, block repeated taps after submission.
- On network error, save the request to a local queue and retry with exponential delay.
- On the server, handle insertion conflicts — return
409 Conflict for duplicate votes.
This guarantees integrity without table locks.
// Android — double-tap protection
viewModel.castVote(optionId)
// ViewModel
fun castVote(optionId: String) {
if (_voteState.value is VoteState.Loading) return
viewModelScope.launch {
_voteState.value = VoteState.Loading
_selectedOption.value = optionId
repository.castVote(pollId, optionId)
.onSuccess { _voteState.value = VoteState.Success }
.onFailure { error ->
_selectedOption.value = null
_voteState.value = VoteState.Error(error)
}
}
}
Why Real-Time Is a Must, Not an Option
For live result updates without page refresh, we use Server-Sent Events (SSE) or WebSocket. SSE is preferable: unidirectional stream from server, simpler proxying and CDN, built-in reconnect. For polls with under 1,000 participants, SSE establishes connections 2x faster than WebSocket and saves up to 40% bandwidth. For enterprise polls with thousands of participants, we use WebSocket via socket.io or native URLSessionWebSocketTask on iOS / OkHttp WebSocket on Android.
| Technology |
Advantages |
Disadvantages |
| SSE |
Simplicity, automatic reconnect, CDN compatibility |
Unidirectional only, no old browser support |
| WebSocket |
Bidirectional, low latency |
Harder to set up, needs balancer support |
On Flutter, we connect SSE using the http package:
final stream = http.Client()
.send(http.Request('GET', Uri.parse('$baseUrl/polls/$pollId/results/stream')))
.asStream()
.expand((response) => response.stream
.transform(const Utf8Decoder())
.transform(const LineSplitter())
.where((line) => line.startsWith('data: '))
.map((line) => PollResult.fromJson(json.decode(line.substring(6)))));
Anonymity with Verification
Some scenarios require: results anonymous, but each participant is a real verified person. We implement via one-time voting tokens: on authentication, the user receives an anonymous token that the server cannot link to identity after issuance. The vote is sent with this token, not user_id. For complex cases, Zero-Knowledge Proof, but for corporate polls, one-way hashing suffices: vote_token = HMAC(user_id + poll_id, secret), where secret is known only to the server and destroyed after poll ends.
Additional verification for anonymous voting
If you need only verified users to vote anonymously, use one-time tokens. On login, the server emits a token unlinkable to the user. The vote is sent with the token, not user_id. To destroy the link after voting, use a salted hash.
Question Types and Their Implementation
| Type |
Implementation Features |
| Single choice |
Radio buttons, idempotent vote endpoint |
| Multiple choice |
Checkboxes, min/max validation |
| Rating scale (NPS) |
Slider or buttons 1–10, neutral state |
| Ranked choice |
Drag-and-drop, ReorderableListView (Flutter) |
| Open text |
TextEditingController, character limit, moderation |
| Matrix / grid |
Custom component, heavy on narrow screens |
The most labor-intensive type is Ranked choice. On iOS, we use UICollectionViewDiffableDataSource with drag interaction; on Android, ItemTouchHelper.
Notifications and Poll Lifecycle
Push notifications for poll start and end via Firebase Cloud Messaging. On iOS: UNNotificationServiceExtension customizes the notification — adds results or progress bar without opening the app, as per App Store Review Guidelines section 5.1. On Android: NotificationCompat.BigPictureStyle for rich notifications with percentages.
Server response time under 10,000 concurrent votes is less than 50 ms. Throughput — 10,000 requests per second.
What's Included
- Requirements audit: question types, scale, anonymity needs
- Data schema and API design
- Mobile client development (iOS/Android/Flutter/React Native)
- Integration testing for concurrent voting
- Load testing (up to 100,000 simultaneous requests)
- App Store and Google Play publishing
- Documentation and client team training
- 30 days post-launch support
Our experience: 5+ years in mobile development, 50+ voting projects, including apps for 100,000+ users. We'll assess your project — contact us for a consultation, and we'll propose a turnkey solution.
Work Process
Audit → design → development → integration testing → load testing → publishing.
Timeline
Simple app with one question type and basic analytics: from 4 to 6 weeks. Full platform with multiple types, real-time, anonymity, and admin panel: from 3 to 4 months. Cost is individually calculated.
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.