SubZero - Offline Subscription Manager and Expense Tracker

SubZero is a premium, offline-first Flutter app template designed to help users track active subscriptions, control recurring bills, and analyze their daily financial habits. Developed by Stacklyn Labs, this application combines Flutter with a local Hive database, Riverpod state management, and a Glassmorphism UI design.

Current Version: 1.4.0 (Consent, Reminders and Backup Fixes)
Technology Stack: Flutter 3.x (tested with 3.44), Hive NoSQL, Riverpod, PDF Generation
Application Category: Finance, Utilities, Budgeting, Productivity
Monetization Ready: Google AdMob (Interstitial Ads Integrated) with a Google UMP consent flow

Web Live Preview
Quick Setup Guide
Complete Setup Guide

Demo Instructions

SubZero is an offline app. There is no login, no email and no password. Open the Web Live Preview and the app starts directly with sample subscriptions.
Optional: enable Settings > App Lock and choose any 4-digit PIN to try the lock screen (the PIN is only stored on the device).
Backup/Restore, PDF export, reminders and ads are available in the Android and iOS builds, not in the web preview.

Why Choose SubZero?

SubZero is an offline-first subscription tracker: no account, no backend server and no bank connection are needed. Subscriptions, settings and the PIN stay on the user’s device, which makes it a simple base for apps that manage recurring expenses, SaaS payments, and gym memberships without cloud hosting costs.

What’s New in Version 1.4.0

• Google UMP consent flow: ads are only initialised after consent allows it, with an “Ad privacy options” entry and an in-app privacy statement.
• Reliable reminders: billing dates roll forward after every cycle, reminders are rescheduled automatically and cancelled when a subscription is deleted.
• Backup restore fix: restored subscriptions can be edited and deleted normally.
• Release-ready setup: unique app ID, targetSdk 36 and documented release signing.
• Better documentation: screenshots, Troubleshooting/FAQ and consent guide.

Comprehensive App Features

• Visual Spending Analytics: Interactive charts visualize spending by category (Entertainment, Work, Shopping, Personal, and more).
• Smart Bill Alerts: Local notifications remind users one day before a renewal at 9:00 AM local time, helping them cancel unwanted charges in time.
• 25+ Rapid-Add Templates: Add subscriptions instantly with pre-configured templates for services like Netflix, Spotify, Adobe Creative Cloud, AWS, and Microsoft 365, with brand-matching colors and standard pricing.
• PIN App Lock: Optional 4-digit PIN (stored as a salted SHA-256 hash) required when the app is launched.
• PDF Reports: Generate a monthly spending report in PDF format with one tap.
• Backup and Restore: Save and restore all subscriptions as a local JSON file.
• Offline-first: Powered by the Hive NoSQL database. No account, no backend server and no monthly hosting bill.
• Dark and Light Themes: A glassmorphism interface with a manual dark/light switch in Settings (dark by default).

Monetization Ready (Google AdMob)

SubZero comes with pre-configured Google AdMob interstitial ads and a Google-certified UMP consent flow. Add your own AdMob App ID and Ad Unit IDs, publish your consent message in AdMob, and replace the sample privacy statement with your own. The documentation explains each step.

Buyer responsibility: you are responsible for all costs, fees and taxes related to third-party ad services (such as Google AdMob), for your own privacy policy, and for legal compliance in your target regions.

Modern Developer Tech Stack

• Framework: Flutter 3.x for iOS and Android (tested with Flutter 3.44 / Dart 3.12)
• State Management: Riverpod
• Local Database: Hive NoSQL
• Document Generation: PDF
• Notifications: flutter_local_notifications with timezone support
• Monetization: Google Mobile Ads SDK with UMP consent

What Is Included in Your Purchase?

• Complete Flutter Source Code (Android & iOS)
• HTML Setup & Reskinning Documentation with screenshots, Troubleshooting/FAQ and release signing guide
• Free Lifetime Technical Updates

AI Disclosure

AI-assisted tools were used to help produce parts of this item, including source code, documentation text and some graphic assets. All output was reviewed, tested and edited by the author, who is responsible for the final item.

Developed by Stacklyn Labs.