Why I Built PlayMemorize
My name is Christoffer De Geer, and I built PlayMemorize because I believe memory training should be free, fun, and accessible to everyone.
It started with a simple idea: I wanted a clean, distraction-free way to practice memorising the digits of pi. The apps I found were either cluttered with ads, locked behind paywalls, or just not enjoyable to use. So I built my own.
From One Game to Eight
What began as a single pi digit trainer quickly grew. I realised that the same principles - spaced repetition, active recall, pattern recognition - could power many different kinds of learning tools. The goal was always the same: make learning easier in a minimalist, distraction-free way.
Today PlayMemorize includes eight free games:
- Pi Trainer - Memorise thousands of digits of pi, e, the golden ratio, and 40+ mathematical constants
- Memory Game - Classic emoji card matching with adjustable grid sizes
- Geography - Learn countries, capitals, and flags on an interactive map
- Color Memory - A Simon Says-inspired color sequence game with up to 24 colors
- Ghost Memory - Spot the missing emoji from a memorised grid (Kim’s Game)
- Polyglot - Learn foreign vocabulary by matching words to emojis in 14 languages
- Speed Math - Sharpen mental arithmetic with configurable operations and ranges
- Unit Converter - Convert between metric and imperial units, or test your knowledge in game mode
Design Principles
Every decision I made was guided by a few core beliefs:
No accounts, no tracking walls. You open the page and play. Your progress is saved locally in your browser.
Works everywhere. PlayMemorize runs entirely in your browser - phone, tablet, or desktop. No app store downloads. It even works offline once loaded.
Clean and calm. No flashing banner ads, no dark patterns, no countdown timers pressuring you to buy. Just a warm, muted design that lets you focus on the game.
Accessible. Touch targets meet accessibility guidelines. Keyboard navigation works. Screen readers can follow game state. Reduced motion is respected.
The Technology
PlayMemorize is built with Astro and React, pre-rendered as static HTML for fast loading. Emoji rendering uses Twemoji SVGs so every player sees the same icons regardless of device. Sound is generated with the Web Audio API - no audio files to download.
The entire site is open and free. No login. No subscription. No data collection beyond anonymous analytics.
What’s Next
I keep adding games and improving existing ones based on what players tell me. If you have an idea for a new memory game or a way to make an existing one better, I’d love to hear from you.
Thank you for playing. Train your brain, have fun, and never stop learning.
- Christoffer De Geer