Kelvin Chang · builder
Build the change you want to see in the world.
I build the tools I use. Small browser tools for the gaps I kept seeing. One job each, no sign-ups, all in your browser and stored locally. Nothing's saved to the cloud. Try them out, then meet the person behind them.
The tools
19 liveWho doesn't follow you back?
Drop your Instagram export: see who doesn't follow you back, who unfollowed you since last time, who's ghosting your request. Then open profiles in batches.
Which watershed are you in?
Type any U.S. address and see the watershed it sits in (the USGS Hydrologic Unit Code boundary), drawn on a live map, from sub-basin down to local subwatershed.
What exactly is dougan?
豆乾 is an umbrella term, not one food. A field guide to 13 kinds of Taiwanese dried tofu, sorted by how each is pressed, braised, fried, or fermented. Photos and diagrams, runs in your browser.
How old is your cat in human years? (or dog or pet)
Enter your cat's age (or birthday) and see how old they'd be in human years, on the real vet curve (not the multiply-by-7 myth). Live graph you can scrub across, runs in your browser.
Is your wallpaper truly OLED black?
Drop a wallpaper and see what percent is true #000000, the black that switches AMOLED pixels off. Then snap the near-black pixels to pure black and download a PNG. Runs in your browser, nothing uploaded.
Need a QR code for your WiFi?
Turn your WiFi network (or any link) into a QR code, add a caption printed above it, and download a PNG or SVG. Your network password never leaves your device.
How many weeks do you have left?
Enter your birthday and see your whole life as a grid, one box per week: the lived ones filled in, the current one ticking live. Or map any span — in seconds, days, weeks, months or years.
How much time do you have left with your parents?
Enter their birthdays (and anyone else you love) and see the time you statistically have left together, in years, months, days, or visits. Averages, not predictions, counted gently. Runs in your browser, nothing uploaded.
Who is actually winning at Nertz?
Add everyone playing and score every round. Enter a player's leftover Nertz pile plus either the cards they got to the middle or the cards still in front of them, and the other number fills itself in. Optional handicap tells each player how many cards to deal next.
How do you cook the perfect steak?
The easiest, tastiest steak you'll ever make. Salt a rib eye, roast it low to 250°F, then sear it screaming-hot in cast iron. Two numbers do the work. No basting, no resting, plus the videos if you want to nerd out.
Who is climbing to A at Tractor?
Track a game of Tractor (Sheng Ji). Every player gets a card with a − and a +, so you just tap whoever moved; the board keeps everyone climbing from 2 to A, with a chart and history. Turn on Advanced mode for hand-by-hand scoring from the points the opponents captured.
Want the stickers out of a LINE pack?
Paste a LINE Store link and get every sticker as a transparent PNG, at the largest size LINE serves, in one ZIP. Animated packs convert to GIF too. The images go straight from LINE to your device, nothing uploaded.
Want your WHOOP and Oura on any screen?
Dash puts your health numbers on a page you can leave open on a spare monitor, a tablet, or the old Kindle in your drawer. Unlike everything else here, it connects to a server, and this page says exactly what that means before you sign up.
Want your MacBook Pro brighter than macOS allows?
KelvinXDR takes the built-in XDR display up to 159%, and keeps working during protected video from Netflix and Apple TV+. It also controls external monitors and puts a brightness HUD under the notch. Free, open source, and this page explains the install.
Where is my Amtrak train, and when does it actually get here?
Pick the station you are leaving from and the one you are going to. It finds the next train Amtrak is really tracking on that route, then tells you when it is expected at your station, how late it is, and where it is right now. It keeps rechecking on its own while anything is uncertain. Unofficial, not affiliated with Amtrak.
Are the Catan dice really against you?
Tap the two faces you rolled — or just the total — and the board draws what actually came up against what two fair dice owe you. Add players and the log splits by person and by round, with the chart narrowing to one of them. Add or drop dice for any other game.
Nothing opens your iPhone's HEIC photos?
Drop the .HEIC files your iPhone shot and get PNGs back at full resolution, as many at once as you like. The decoder runs inside the page, so nothing is uploaded, and the EXIF and GPS tags stay behind.
Learning backend development?
A complete SI 679 field guide: Weeks 1–4, TypeScript and HW1. Learn Express, MongoDB and REST APIs with worked examples, tests, answer reveals, and all six original walkthroughs.
Who sits as the Great Dalmuti next round?
Track The Great Dalmuti (달무티). Tap the order everyone went out in, and the board seats the next round from Greater Dalmuti to Greater Peon, counts how many rounds each player has held each seat, spells out the taxes each Peon owes, and flips the table on a greater revolution.
In the workshop
More tools land here as I build them.
Oh, and who I am
The humanIt sits in your team's daily work, writes the summaries, captures the decisions, and remembers who did what.
And the person behind the tools. I'm Kelvin, a builder and product manager. I spent ~3 years shipping crypto products at Coinbase, was employee #2 at a pre-seed startup, and studied at the University of Michigan School of Information. These days I'm building Tinu AI.
Where I've built
ExperienceCoinbase · Product Manager
Owned USDC Rewards on Coinbase Prime, launched Wallet Explore 0→1, and shipped ML coin recs, cutting CB Pay's buy-funnel drop-off 60% and Prime reporting time 95%, then led the Prime Canada launch.
Sustainable Bitcoin Protocol · Head of Product
Employee #2 at a pre-seed startup: led product, engineering and design for renewable-energy-certificate verification in Bitcoin mining.
Microsoft · Capstone UX Designer
Redesigned accounts.microsoft.com: new navigation and activation surface, ~2× projected engagement.
EY · Workforce Advisory (PAS)
Change-management personas and impact analysis for a Fortune 500 client.
University of Michigan · M.S. Information
M.S. Information · B.B.A. (Ross, Magna Cum Laude) · B.S. Information (4.0). Taught SI 305: Python & Pandas.