Case Studies

Real projects, told briefly: the situation, how it was done and the numbers that were measured.

Websites and stores20266 min read

Tan Doanh: a custom theme, a PC build tool and installments, mobile PageSpeed from 65 to 96

Tan Doanh (computer parts and prebuilt PC shop) | Computer parts and PC retail

65 → 96Home page mobile PageSpeed, first version vs after tuning (3 Jul 2026)
97 / 100PageSpeed mobile / desktop of the PC build page, measured 8 Nov 2026

The computer-parts shop Tan Doanh needed a page that is fast on phones and a place for customers to put a build together. I rebuilt the theme and wrote a build tool with compatibility checks and installments right on the page.

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Websites and stores20267 min read

IGA: 5,256 gemstone products on a new design, mobile speed from 61 to 99, page addresses kept

IGA (Infinity Gems An Thịnh), a gemstone store | Gemstones, carved stones and feng shui items

61 → 99mobile speed score, old site vs new build
5,256products on a new design, same addresses

A gemstone shop with over 5,000 products was running on a heavy design that was slow on phones. I rebuilt it with a custom theme and plugin, kept every page address, and measured again on a test copy before opening it to customers.

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Apps20268 min read

PixGamma: AI photo upscaling on a Mac, texture error 0.084 vs 0.152, 91% of text read right

PixGamma (my own product, not a client) | macOS app, AI image processing

0.084 / 0.152texture error (DISTS) of PixGamma and its base model, lower is better
91.1%characters on Vietnamese and English banners read correctly after 4x

PixGamma is a Mac app I built to enlarge and restore photos with AI, running entirely on the machine. I measured which model stays closest to the original, retrained it on the Mac itself, and added a separate step that keeps text correct, Vietnamese included.

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Websites and stores20265 min read

phatdev.net: mobile speed from 95 to 99 and content open to both people and AI

phatdev.net (my own project) | Portfolio, docs and plugin updates

99 / 100PageSpeed mobile / desktop, 18 out of 18 runs
2.8 s → 1.9 stime for the main part of the home page to show on mobile (LCP)

My own personal site also runs the docs and plugin updates. I measured it, fixed what sits before the page appears, and made the same content readable by browsers, Google and AI.

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Infrastructure and sync20265 min read

Tan Doanh: a test copy that always matches the live shop, push on save plus a nightly check, 0 mismatches

Tan Doanh (computer parts and prebuilt PC shop) | Computer parts and PC retail

~10 sfrom saving on the real site to the test copy receiving it (operations notes, not re-timed)
0 mismatchesacross 5,139 products and 213 variations, nightly check at 03:10 on 8 Nov 2026

Nobody dares to try a new theme on a shop that is selling. I built a test copy of Tan Doanh and keep it in step with the real site through three one-way sync layers, with the real site read only.

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Internal software20265 min read

Tan Doanh ERP: inventory, sales, warranty and accounting in one app, now in a trial run

Tan Doanh and IGA (internal use) | Retail, inventory, sales and accounting

126business screens, counted in the source on 8 Nov 2026
120+database migration files, numbered up to 140, counted 8 Nov 2026

Stock, orders, cash collected on delivery, warranty and accounting numbers sit in many places, each counted its own way. I built an internal app for Tan Doanh on one foundation rule: a written entry is never edited, only reversed.

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AI and content20266 min read

IGA Social: 303 clips built, 293 on YouTube, and a week of Facebook posts from one button

IGA (Infinity Gems An Thịnh), a gemstone store | Gemstones and feng shui items, social media content

303video clips built and stored
293clips already on YouTube

A gemstone shop has to post steadily, but hand-written captions vary every time and free-running AI tends to make things up. I gathered the work in one internal app: AI only drafts inside rules, and a person always decides.

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WordPress20266 min read

SL Migrations: 6 restore modes for WordPress, on 40+ sites, with AES-256 encrypted backups

SL Migrations (my own in-house tool) | WordPress, backup and site migration

6restore modes, from Recovery Point to Two-Part for large sites
40+sites sharing one build of the plugin

Backing up and moving a WordPress site by hand takes time and breaks easily, and ready-made plugins charge per site. I use one shared plugin across more than 40 sites, split restoring by real situations, and fixed it through real restores.

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Apps20266 min read

CreditMate: a credit card app with no server and 1,864 tests behind its money maths

CreditMate (my own product, not a client) | iOS app, personal finance

1,864domain tests for money, ledger, instalments and statement parsers
110UI tests running on iPhone and iPad

CreditMate is an iPhone and iPad app I built to bring credit cards, loans and pay-later wallets from several banks into one place, with the data kept on the device. I wrote the money rules first and drew the screens after.

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AI and content20265 min read

Media Studio: photos, banners and review videos from one link, AI photo match from 72 to 89

Media Studio (my own tool, not a client) | Content automation, AI images and video

4,721images generated in the library (18 Oct 2026)
9tools in one dashboard, plus a library

Media Studio is a tool I built to produce review content for tech devices: photos, banners, voice-overs and video, all callable through an API. I let a machine score the AI photos, built banners in layers and gave every engine a fallback.

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