Product Engineer & Mobile Lead

Huy Nguyen (Roy)

Product Engineer with 7 years of Web & Mobile experience combined with 2 years of intensive finance studies focusing on Fundamentals and Macro-driven.

Combining software engineering expertise with stock market data research capabilities.

7+

Years Dev Experience

2+

Years Financial Study

2019 Mobile dev at boop.date

2021 FE & Mobile IOT apps Engineer at
TZ.NET (TZ Limited)

2024 Dashboard web Engineer
at smartlox.io

2026 Learning Finance, Investing
and creator of Paperhands.vn

The Problem

Lack of Fixed Strategy: Most retail investors trade arbitrarily without a consistent, structured system.

Inexperienced F0 Pitfalls: New investors lose money quickly; existing simulators only show current status, neglecting daily or hourly historical backtesting.

No Clear Goals & Psychology: Investing without defined risk/reward expectations or awareness of emotional and psychological biases.

Aggressive Margin & Hidden Fees: High-leverage products are marketed to beginners, carrying hidden interest fees and liquidation risks.

Complex Market Mechanics: Nuances like corporate actions (dividends, rights issues), taxes, and trading fees are highly confusing for novices.

My Solution: https://paperhands.vn

A high-performance stock market simulator and backtesting engine for the Vietnamese market.

Price & Volume Check price movement and market volumes.

Financial Analysis Examine balance sheets and corporate statements.

Valuation History Track historical P/E and P/B valuation trends.

Simulated Trading Trade mock portfolios with margin & time-travel.

Data Provider

Financial Data Source Comparison

P/E ratios, forward P/E, industry P/E, sector comparison, and momentum. Plus customize to meet business requirements. Update daily. Both support live tick price supported.

Financial Data Provider

Standardized Global

Financial Modeling Prep (FMP)

Locally Optimized

Local Provider (Domestic)

Pros

Global Standard: Clean schemas, consistent structures, and documented endpoints.

Easy Scaling: Simple multi-country expansion out of the box.

Real-Time Accuracy: Near-instant updates synchronized directly with local exchanges.

Corporate Actions: Accurate data adjustments for stock splits and rights issues.

Cons

Local Feed Delay: Tickers from local exchanges suffer update latencies.

Price Chart Errors: Historical price charts can be inaccurate, particularly for micro-cap stocks with frequent splits and rights issues.

Hard to Scale Globally: Custom local schemas make international expansion complex.

System Design

Web App + BE Python + Notification

A scalable three-tier model engineered for security, high throughput, and alerts.

Web App / Dashboard

Responsive dashboard to filter, sort, search, and scan tickers.

Renders stock P/E ratios (current, forward, industry).
Highlights momentum and sector trends.

Secure Backend API

Performs logical operations, caches data, and manages credentials.

Calculates earnings trends and momentum.
Isolates financial API keys server-side.
Secures database writes.
Custom data calculation on request

Alert & Notification

Background workers periodically checking market indicators against filters.

Asynchronous queues handle alerts without overload.
Pushes alerts via Email, Telegram, or In-App.

Data Security

Solid practices implemented to protect backend assets and user records.

Protected API Keys: API credentials are kept strictly server-side and accessed via secure BE proxies.

JWT Authentication: Secures client sessions using short-lived tokens and MFA.

Transport Safety: Enforces HTTPS/TLS encryption and strict CORS rules.

Deliverables

Interactive API Docs: Swagger/OpenAPI parameters playground.

Full Source Code & Document: Protected, all progress.

Tools & Utilities: Backup data, scripts, tools to verify data logic and results, tested models.