BondCheck
BondCheck solves a massive operational inefficiency for retail bondholders in Pakistan by automating the checking process against decades of historical draw data.
The Operational Bottleneck.
Millions of Pakistanis hold prize bonds but check results manually, copying numbers one by one to the official National Savings site, a painful process for anyone with more than a few bonds.
Architectural fragility resulting from manual workflows, unindexed datasets, or third-party template limits.
The Engineering Strategy.
We built a privacy-first React app with an Express proxy that scrapes official draw results. Users save their bond numbers once (singles and consecutive series) and BondCheck matches every one against every draw in one click. Data never leaves the browser.
How the system was constructed.
A privacy-centric architecture where all portfolio data remains strictly in LocalStorage/IndexedDB. The backend serves purely as a high-speed data pipeline for public draw results.
Client Engine
React SPA handling heavy array-intersection logic in a Web Worker to prevent UI blocking.
Scraping Pipeline
Python/FastAPI microservice executing weekly cron jobs to scrape, parse, and clean official PDF/HTML draw results.
Database
PostgreSQL storing normalized draw data, optimized with GIN indexes for fast querying.
Engineering Challenges Overcome.
Browser Memory Limits
Checking a portfolio of 10,000 bonds against 20 years of draws (millions of winning numbers) caused memory crashes. Solved by chunking the intersection algorithm and utilizing Web Workers.
Unreliable Upstream Data
The official government data sources often have formatting errors or downtime. We implemented robust error handling, historical caching, and automated anomaly detection.
Technology Selected.
Engineered with modular, standards-compliant tooling designed for zero lock-in and high-speed execution.
Production Capabilities Shipped.
One-click check across all draws
Series-aware portfolio management
Google Drive backup & Excel import
Full history scan: every past draw
Reduced a multi-hour manual checking process down to under 2 seconds. The platform operates with near-zero variable server costs due to the client-heavy compute model.
Pairs Arcade
Mini Arcade with Online Multiplayer
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