Case Study

BillKoto - Electricity Bill Calculator & Insights

Production Android app computing step-up electricity tariffs across Bangladesh power distribution utilities with device power modeling and offline NoSQL persistence.

Year: 2026 Role: Lead Mobile Engineer FlutterRiverpodHive NoSQLFirebasefl_chartAndroid
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BillKoto screen 1
BillKoto application feature screen 1
BillKoto screen 2
BillKoto application feature screen 2
BillKoto screen 3
BillKoto application feature screen 3

Executive Overview

BillKoto (বিল কত) is a specialized production mobile application available on the Google Play Store. It simplifies complex electricity billing calculations for household and commercial consumers across Bangladesh by providing precision step-up tariff calculations, device-level consumption modeling, and actionable energy-saving insights.

Problem Statement

Electricity tariffs in Bangladesh operate on progressive multi-tiered slab structures governed by 6 major distribution companies (BPDB, NESCO, DESCO, DPDC, BREB, WZPDCL). Consumers frequently face difficulty forecasting monthly power bills, understanding demand charges, or identifying high-consumption household appliances before the bill arrives.

Architecture & Engineering Highlights

  • Multi-Utility Tariff Engine: Built a configurable mathematical calculation engine supporting tiered pricing slabs, vat rates, demand charges, and meter rent adjustments for all 6 regional utility providers.
  • Device-Level Power Modeling: Implemented appliance-wise energy usage breakdown algorithms that convert device wattage and daily operating hours into monthly cost projections.
  • Offline-First & Zero-Friction Storage: Engineered local persistence using Hive NoSQL, enabling sub-millisecond read/write speeds with zero network dependency or registration barriers.
  • State Management & Codegen: Structured state architecture using Flutter Riverpod 2.6 with riverpod_generator for strict immutability, testability, and isolated UI updates.
  • Localization & Analytics: Full bilingual support (English & Bengali) using easy_localization, paired with Firebase Suite (Analytics, Crashlytics, Performance Monitoring) for real-time telemetry.

Features & Visualizations

  • Dynamic tariff calculator with automatic slab progression indicators.
  • Appliance load manager pinpointing high-wattage power consumers.
  • Interactive monthly trend charts powered by fl_chart.
  • One-tap bill summary export and native sharing capabilities.

Production Status

Published live on the Google Play Store under package com.codenity.billkoto, serving users with high accuracy and zero user registration friction.