HueTrace.
Color Memory Game
HueTrace is a quiet, focused game about how well you actually see color. A color flashes on screen, disappears, and you rebuild it from memory on a hue ring and saturation square. Every guess is measured with CIEDE2000 — the perceptual color-difference formula used in print and design — so a guess that looks close scores close. Four modes cover different skills: Classic for single colors with three tries, Sequence for runs of three to seven colors recalled in order, Blitz for sixty seconds against the clock, and a Daily Challenge where everyone gets the same five colors on the same date, generated from the date itself with no server involved. Rounds step up through five difficulty tiers, close matches chain into combos, and a colorblind-friendly mode keeps every color distinguishable with red-green color blindness. Built with React Native, Expo (SDK 57), Skia-drawn color wheels and result rings, Reanimated 4, and a pure-TypeScript game engine covered by a 200-plus-case test suite.
What it does.
Four Modes: Classic, Sequence, Blitz & Daily Challenge
Perceptual Scoring with CIEDE2000
Same Five Daily Colors for Everyone
Five Difficulty Tiers, Warm Up to Master
Combos, Streaks & Streak Freezes
Shareable Daily Result Card
20 Achievements to Unlock
30-Day Score History & Personal Bests
Colorblind-Friendly Mode
Optional Daily Reminder
Light & Dark Mode with Six Theme Packs
No Account, Fully Offline
Ads Only When You Ask, One-Time Unlock
How it’s built.
See It. Hold It. Recreate It.
Each round has three phases: a target color fills the screen for a moment, then disappears, and you rebuild it from memory on a hue ring and saturation-brightness square. The result ring shows the target and your guess side by side, with a score from 0 to 100.
- Full-screen target, shown for a moment only
- Hue ring plus saturation and brightness square
- Target and guess compared side by side
- Scored Perfect Match, Very Close, Close, Off or Way Off
- Hue-family hints during the warm-up rounds
Scored the Way Your Eyes See
Both colors are converted to CIELAB and compared with CIEDE2000, the color-difference formula used in print and design. It follows perception rather than raw numbers, so two colors that look close score close even when their RGB values are far apart.
- CIEDE2000 perceptual color difference
- Scores that track what the eye notices
- Hex values of target and guess, if you want them
- Stricter pass marks as rounds get harder
Four Ways to Play
Classic, Sequence and Blitz are always open; the Daily Challenge unlocks a new set of five colors at midnight.
- Classic — one color at a time, three tries, as long as you last
- Sequence — three to seven colors in a row, recalled in order
- Blitz — sixty seconds; close matches add time, misses cost it
- Daily Challenge — the same five colors for everyone on the same date
- Five difficulty tiers from Warm Up to Master
A Daily Habit
One Daily Challenge a day keeps your streak alive, and a streak freeze covers a missed day. Your result becomes a share card, and an optional reminder can nudge you when the next set is out.
- Streaks with streak freezes
- Shareable result card with a per-color breakdown
- Optional daily reminder at a time you choose
- 30-day score history and personal bests
- 20 achievements to unlock
Tools used.
- React Native
- Expo (SDK 57)
- React Native Skia
- Reanimated 4
- TypeScript
- Expo Router
- MMKV on-device storage
- 100% Offline — no server, no accounts
- Local notifications for reminders
- RevenueCat for the one-time unlock
- Google AdMob rewarded ads (opt-in only)
- Pure-TypeScript game engine and CIEDE2000 color math
- Seeded daily generation — identical on every device
- Dichromacy simulation for colorblind-safe palettes
- 200+ case test suite on the Node test runner
Perfect for
Common questions.
Yes. HueTrace is free to download and play, with every game mode available to everyone. Ads appear only if you choose to watch one for a bonus Daily Challenge retry. An optional one-time purchase — not a subscription — removes ads and unlocks every theme pack. Themes are cosmetic, so paying never changes how the game plays.
The five colors are generated from the calendar date itself, using a seeded generator. Every device produces the same five on the same date, so no server is involved and the Daily works offline.
Both colors are converted to CIELAB and compared with CIEDE2000, a perceptual color-difference formula. A difference too small to notice scores near 100, and the score falls away as the difference becomes obvious.
Yes. Turn on colorblind-friendly colors in Settings and every color in a run is chosen to stay distinguishable with red-green color blindness. The Daily Challenge always uses this mode, so it is fair for everyone.
No. There is no account and no analytics, and your scores, streaks and settings stay on your device. The only outside services are Google AdMob, for the optional rewarded ads, and RevenueCat, to verify the one-time purchase — the privacy policy lists exactly what they receive.
React Native, Expo (SDK 57), React Native Skia for the color wheel and result rings, Reanimated 4 and TypeScript — with a pure-TypeScript game engine and color-math library covered by an automated test suite.
How well do you remember color?
See a color, hold it, and find it again on the wheel — with a new five-color Daily Challenge every day.