Khanh Duy

Khanh Duy Command Center

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Bui Trong Khanh Duy / Product builder / Ho Chi Minh City

Building practical apps for focus, fitness, and family logistics.

I'm Khanh Duy, a full-stack developer in Ho Chi Minh City. My current work centers on three focused apps: LofiHood for calm Mac playback, SpotterFuel for crowded-gym workouts, and CampusCue for school notice follow-through.

Explore the appsOpen tools and agents
Experience

5+ years

Current apps

3 apps

Free tools

20 tools

AI agents

13 agents

Stack

JS / TS / React

Khanh Duy

Currently

Vietnam / GMT+7

Shipping small products that solve a specific job well.

Current apps

Three focused products, built around specific moments of friction.

Each app starts with a clear everyday interruption and turns it into a simple next action.

03

macOS menu bar applofihood.com
LofiHood
Offline lofi that stays out of your way.
LofiHood product preview

A local-first lofi player for the Mac menu bar with bundled tracks, mood filters, local albums, imports, shortcuts, and a sleep timer.

macOSlocal-firstmood presetscoming soon
  • Bundled offline tracks
  • Mood and album filters
  • Menu-bar playback controls
Visit LofiHood
iPhone fitness appspotterfuel.com
SpotterFuel
Keep training when the equipment is taken.
SpotterFuel product preview

Mark blocked gym equipment and find same-muscle alternatives so a crowded station does not derail the session.

iPhonesame-muscle swapsequipment-awareApp Store
  • 119 exercises
  • 17 muscle groups
  • 16 equipment types
View SpotterFuel
iOS app for parentscampuscue.app
CampusCue
School notices become reviewed action cards.
CampusCue product preview

CampusCue turns flyers, PDFs, screenshots, and shared files into cards parents can review before adding anything to Calendar or Reminders.

local-firstreview firstiOSTestFlight waitlist
  • Flyers, PDFs, screenshots
  • Parent review before handoff
  • Calendar and Reminders flow
View CampusCue

Browser workbench

Tools and agents for the work around the apps.

Use small browser agents for summaries, extraction, planning, data cleanup, and prompt work. Use private browser tools for JSON, QR codes, images, PDFs, text, colors, timestamps, and everyday utility tasks.

AI agents

Representative browser-first agents from the full catalog.

Browse agents
Email DigestTurn long email threads into decisions, blockers, and replies.File to DataUpload text, CSV, JSON, or logs and get structured data back.Private SummarizerSummarize pasted content locally before anything touches a server.Day PlannerTurn a messy life-admin brain dump into a realistic day plan.

Free tools

Private, no-signup browser utilities for everyday tasks.

Browse tools
JSON FormatterFormat, validate, and inspect JSON payloads without uploading data.QR Code GeneratorCreate QR codes for URLs, Wi-Fi credentials, contacts, and short text.Image CompressorShrink large screenshots and product images before uploading.Images to PDFCombine receipts, screenshots, and scans into a single PDF file.Palette From ImageExtract a usable color palette from a product or brand image.Timestamp ConverterConvert Unix timestamps into readable local and UTC dates.

About

Built by Khanh Duy in Ho Chi Minh City.

I design and ship web, iOS, and macOS products with a focus on practical workflows, clear interfaces, and fast iteration across React, TypeScript, Next.js, and app-platform tooling.

EmailGitHubLinkedIn
stack.ts

const stack = [

'Next.js', 'React', 'TypeScript', 'Tailwind CSS', 'Node.js', 'Vercel'

];

// Ship small. Iterate fast. Focus on usefulness.

Practical first

Start with a real interruption, then ship the smallest useful loop.

Build clearly

Readable interfaces, typed code, and fast iteration over ceremony.

Keep it usable

Polish the details that make an app easier to return to.