Why I Built PlayMemorize
TLDR: PlayMemorize is a free, ad-free collection of 80+ browser-based memory and learning games built by Christoffer De Geer. It covers memory, reasoning, language, numbers, and attention - all playable without sign-up or payment, designed to stay out of your way so you can just practice.
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.
The core belief: memory training works best when the tool stays out of your way. No interruptions, no upsells, no timers pressuring you to buy. Just practice.
From One Game to a Whole Catalogue
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.
Every game on PlayMemorize uses one of three cognitive techniques. Spaced repetition for long-term retention (Pi Trainer, Polyglot). Active recall for rapid consolidation (Memory Game, Ghost). Pattern recognition for fluency (Color Memory, Speed Math). Pick the one that matches what you’re trying to learn.
Today PlayMemorize includes more than eighty free games, spanning memory, reasoning, language, numbers, and attention training. Here are a few to start with:
- Labyrinth - Walk a fog-of-war maze and beat short challenges drawn from every other game, level by level
- Pi Trainer - Memorise thousands of digits of pi, e, the golden ratio, and 38 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 all 25 languages
- Speed Math - Sharpen mental arithmetic with configurable operations and ranges
- Estimation - Pick the bigger quantity across wildly different scales
- Number Sequences - Find the next number in arithmetic, geometric, Fibonacci, prime, and power sequences
- Pattern Recognition - Raven’s Progressive Matrices style pattern completion
- Chess Mate - Spot the checkmate-in-one on a real board
- Wordle - Guess the hidden five-letter word in six tries
- Spatial Reasoning - Find the rotated match among mirrored distractors
- Verbal Analogies - Complete word-pair analogies across function, location, part-whole, cause-effect, synonyms and antonyms
- Stroop Test - The classic color-word interference test that measures selective attention
- Facts - Spot the one true statement among several generated claims about math, calendar, and geography
- Define - Build vocabulary by picking the correct meaning of a word from multiple choices, in every one of the 25 languages
- Backwards - Read words in reverse and pick the forward-reading match from the options, with a millisecond-precision timer
- Riddles - Solve classic, logic, math, and wordplay riddles across adjustable difficulty, type, and choice counts in streak mode
Design Principles
Every decision I made was guided by a few core beliefs.
Play instantly - sign in only if you want. You open the page and play, with no account required to start. Create a free account (just an email, no password) to sync your progress across devices, join the country leaderboard, and collect badges.
Works everywhere. PlayMemorize runs entirely in your browser - phone, tablet, or desktop. No app store downloads. It even works offline once loaded, so you can train on a plane, a train, or anywhere else the wifi drops.
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 by default. Touch targets meet WCAG guidelines. Keyboard navigation works. Screen readers can follow game state. Reduced motion is respected. These are not afterthoughts - they are the default.
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 whole site is open and free, with no subscription. An optional free account (email only, no password) stores your stats so they sync across devices and feed the leaderboard; play without one and your progress stays in your browser.
Privacy note: PlayMemorize uses privacy-respecting analytics to measure page views and which games people play. If you create an account, we store only your email address and your game stats - never a password. See the privacy policy for the full picture.
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
