Answer as many arithmetic questions as you can in 60 seconds, built with pure React (no game engine). Bright arcade neon look.
How to play
Pick a difficulty and which operations to include, then press Start (or Enter).
Type the answer with your keyboard or the on-screen number pad. It's checked automatically once you've typed as many digits as the answer has. Backspace fixes a digit.
Each correct answer scores 10 points times your combo multiplier.
Every 3 correct answers in a row raise the multiplier by one, up to ×5.
A wrong answer resets the combo to ×1 and costs 3 seconds; the same question stays until you get it right.
Measure how fast you react to a color change, built with pure React (no game engine).
How to play
Click, tap or press Space to start.
The screen turns red — wait. After a random delay (1.5–4.5 seconds) it turns green.
Click, tap or press Space as soon as it turns green. Your reaction time is shown in milliseconds.
Clicking before green shows Too soon! and counts that attempt as a miss.
Each session has 5 attempts. Your average uses only the valid attempts.
See how fast and accurately you can type, built with pure React (no game engine). Dark code-editor look.
How to play
Pick a test length (15, 30 or 60 seconds) from the editor tabs.
Start typing the words shown. The timer starts with your first keystroke.
Press Space to move to the next word.
Mistakes are shown in red and counted, but you can keep going. Use Backspace to fix the current word, or press Backspace on an empty word to go back and fix the previous one if it has a mistake.
When time runs out, you see your results.
