Đào Công Thành - Tennis Coach & Independent Builder

From the tennis courts of Helsinki to string physics, music, and sports tech.

I am a tennis coach first. I didn't set out to build software for the sake of it - I just followed what excited me, solving real-world problems as they appeared. A years-long curiosity about string tension and player health led to a mechanical physics database. A passion for melody turned into multiple instrumental albums. As an avid tennis and badminton player who loves filming my own matches, the sheer friction of scrubbing through my own footage led to Velox. When I needed a clean QR code to share Velox without getting scammed by dynamic paywalls, I built Pure QR. And when a 100-person tournament gala dinner almost collapsed under paper raffle slips, FairDraw was born.

No corporate roadmaps, zero predatory subscriptions. Just a coach following genuine excitement to build honest, high-performance things for athletes, creators, and curious minds.

Chapter 1 • Equipment Physics • 2020 - Present 10–30kg Load Testing

Thanh's String Elongation Lab

It started on the tennis court years ago with a tensiometer, a notebook, and a coach's curiosity: how do dynamic tension loss and stiffness curves impact arm fatigue and ball pocketing? I tested tensile elongation and hysteresis loops across 10+ string models under loads from 10kg to 30kg. Thanks to modern AI coding assistance, I finally published this comprehensive material dataset online as an interactive visualizer for coaches, stringers, and players.

Tensile Elasticity 10+ String Models Arm Safety & Hysteresis Dynamic 10–30kg Curves

Open String Lab Interactive Research Lab

Chapter 2 • Sonic Exploration • 2023 - Present Global Streaming

Instrumental Soundscapes

Stepping away from physical athletics into auditory excitement. I write, produce, and distribute original instrumental albums across New Age and World genres. From the grounding reflection of Trở Về (Return) to the vibrant melodies of Hi, Have We Met? and World, each track is created with honesty, peace, and high energy. Available on Spotify, Apple Music, and all major platforms.

New Age World Genres Composer & Producer DistroKid

Listen to "Trở Về"

Hi, Have We Met? World

Chapter 3 • Racquet Video AI • Started Nov 2025 AI Video Slicing

Velox - Racquet Rally Cut

Born directly from player frustration: as an avid tennis and badminton player, I love filming my own practice and match sessions, but reviewing them meant scrubbing through 75% dead time of picking up balls and walking between points. So I engineered Velox - high-speed match rally segmentation for Tennis, Badminton, Padel, Pickleball, Squash, and Table Tennis. It cuts dead time automatically, works 100% offline for free manual editing, and burns custom game scoreboards into exported clips. No mandatory monthly subscriptions.

On-Demand LLM Vision Offline Video Slicing Dynamic Scoreboard Pay-As-You-Go Carats

Visit Velox Hub

Google Play TestFlight (iOS)

Chapter 4 • The Accidental Utility • Started Apr 2026 100% Client-Side • Never Expires

Pure QR

The punchline of the journey: I literally just wanted to create a simple QR code to put on court flyers and stickers promoting Velox. Instead, online tools demanded credit cards, injected tracking redirects, or threatened to deactivate the codes after 14 days. Frustrated by predatory paywalls, I built Pure QR - a high-resolution vector QR designer with custom colors, logo embedding, PWA offline support, and instant lossless PNG/SVG exports. 100% client-side, zero tracking, and never expires.

Vector SVG Engine Zero Server Storage No Expiration or Redirects PWA & Multi-Language

Launch Pure QR Global • Free Forever

Chapter 5 • Frictionless Synchronicity • Apr 2026 - Oct 2026 Published Oct 2026 • Live Events

FairDraw - Real-Time Lucky Draws & Giveaways

Born at the VBE 2026 tournament after-party in Helsinki when 100 players were 15 minutes away from a paper raffle crisis. I engineered FairDraw: an ultra-fast, zero-friction lucky draw engine. Dual-surface remote control lets organizers project a distraction-free stage on the big screen while running the draw from their phone in their pocket. Zero app install, zero PII, 45-second live winner claim window, and 100% ad-free presentation stages.

Real-Time Firestore Listeners Apple Dynamic Island Telemetry Dual-Surface Remote Control Zero-PII & Web Crypto Keys Live 45s Claim Window

Launch FairDraw

Read Architecture →

The Engineering Manifesto

Core architectural philosophies governing every piece of software built under this domain.

1. Client-Side Sovereignty

Whenever technically possible, computation executes locally on the end user's hardware. Whether compiling vector graphics in Canvas/SVG or slicing high-bitrate sports video footage in local storage, your data stays in your physical control rather than being collected on a centralized server.

2. Anti-Subscription Ethics

Modern software has become bloated with mandatory, expensive recurring subscriptions for basic utility. My software prioritizes robust offline-first functionality for free, coupled with fair pay-as-you-go billing (such as Velox Carats) solely for computationally intensive cloud AI tasks.

3. Athletic Precision & Speed

Tools built for athletes and engineers must operate with zero perceptible latency. Every application is optimized for instantaneous loading, sub-100ms interaction responses, clean standards-compliant code, and strict adherence to modern web standards without unnecessary dependency overhead.

From the tennis courts of Helsinki to string physics, music, and sports tech.

The Creative Domino Effect

Thanh's String Elongation Lab

Instrumental Soundscapes

Velox - Racquet Rally Cut

Pure QR

FairDraw - Real-Time Lucky Draws & Giveaways

The Engineering Manifesto

1. Client-Side Sovereignty

2. Anti-Subscription Ethics

3. Athletic Precision & Speed

Engineering & Coaching Journal

The Sunday Evening Rescue: Engineering FairDraw

The Mechanics of Tennis String Elongation

Exposing Predatory Dynamic QR Redirects

Automating Racquet Match Telemetry

The Client-Side Sovereign

From the Court to Composition

The Coach's Eye

About the Coach & Creator

Connect & Follow