About Pickboard

Pickboard is a free set of tools for picking at random: a wheel, a ladder game, a name picker, a team generator, random numbers, a coin and dice. It is made by Lumen Lab, a small studio in Korea that builds apps and web tools. There is no sign-up, and the list you type stays in your browser.

How a pick is made

Every time you press the button, the page asks your browser for 32 random bytes with crypto.getRandomValues(). MDN describes that method as giving cryptographically strong random values (MDN: Crypto.getRandomValues()). We do not use Math.random(), which MDN says does not provide cryptographically secure random numbers (MDN: Math.random()).

Those 32 bytes are the seed. The seed starts a small generator called xoshiro256**, and every number the draw needs comes from it. Because the generator is deterministic, the same seed with the same list and settings always gives the same result. That is what makes the result link work: the link carries the seed, the list and the settings, and anyone who opens it gets the same outcome rebuilt on their own device.

Whole numbers are taken without bias. To pick one of n items the page draws only as many random bits as n needs and discards any value that is n or more, then draws again. It never divides and keeps the remainder, which would make some items very slightly more likely.

Orders, teams and multi-name draws use the Fisher–Yates shuffle in the form published by Richard Durstenfeld in 1964 and described as Algorithm P in Donald Knuth’s The Art of Computer Programming, volume 2. Every possible order is equally likely.

What we do not build

There is no way to make a chosen name come up, on any tool, hidden or otherwise. The wheel decides the result first and then turns to it, so what you see is what was drawn. The ladder game shuffles its bottom row before building the ladder, because a plain ladder favours nearby positions; the ladder guide shows the numbers.

How it is tested

The picking code is separate from the screens and has more than 400 automated tests. They compare the generator with reference values computed independently in Python, draw 100,000 times with fixed seeds and apply a chi-square test to check that outcomes are even, verify that every generated ladder is a one-to-one mapping, and confirm that a result link reproduces the same result. The tests were also run against deliberately broken versions of the code to make sure they fail when they should.

Limits worth knowing

A result link shows that a result was not changed after it was drawn. It cannot show how many times someone drew before choosing which link to send. If that matters, agree on one draw in advance or draw on a screen everyone can see. This site is for classrooms, meetings and games, and is not meant for draws that need a formal audit.

What is stored

Your list, recent results and sound setting are saved in this browser only. See the privacy policy for the exact items and how ads work.

Fonts and contact

The site uses the Pretendard typeface by Kil Hyung-jin under the SIL Open Font License. Questions and corrections: woxocoso@gmail.com.