first principles
Principles
We ship pixels in the right order, with the right reactions.
Nine rules keep them right: three for which pixels show, three for the order they arrive in, three for how they react. Each one is a toy. Play with it, and it shows you what it means.
which pixels
Strong Defaults
The first value should already be the right one. Most people never change it.
optimal size · the default
Proper Hierarchy
Size and order say what matters before a single word is read.
tap to optimize
Clear Conventions
What looks pressable is pressable, and answers when you press it.
looks like a button · press it
in what order
Complication on Demand
Start simple. Detail unfolds when someone asks for it, not before.
tap for detail
Minimize Cognitive Load
Show the next step, not every step at once.
all five at once · tap one to focus
Chain of Fallbacks
When the best path fails, the next one still gets you there.
optimal behavior
with what reaction
Reasonable Effort
Easy to do, hard to undo by accident: only destruction asks twice.
submit, or remove
Fine-Tuning
Good defaults to start with, and the controls to tune them to your needs.
the default · close for most
Automate Whenever Possible
If a machine can repeat it, a person should not have to.
nothing to press · it plays itself
Make it feel like a game
The tenth rule, and the reason for the other nine. Play all nine to write it in.