← The teachingsOne complete piece before you widen

Build the Slice

One complete piece before you widen

The teaching
Build one thing all the way through — every layer, ugly, working — before you build anything wide. Breadth first makes every problem arrive at once.
Before the laws
The builds that failed were built wide: every screen sketched, every table designed, nothing running end to end. Then integration day came and every integration problem surfaced together, and there was no way to tell which one mattered. The builds that lived were built deep: freeze the contract, verify the data alone against real records, one complete vertical slice, then widen.
1 of 4
Freeze the contract before you design.
Because designing against a moving target means designing twice.
Write down what the thing takes in and what it gives back. Don't touch a screen until that's still.
2 of 4
Verify the data alone, against the real, messy version.
Because the real records have broken dates and missing years, and a design built on clean examples breaks on the first real one.
Pull ten real examples. Look at the worst three. Design for those.
3 of 4
One slice, every layer, then widen.
Because a slice that runs end to end teaches you what the other slices need before you build them.
Pick the smallest complete path. Make it work. Only then add a second.
4 of 4
Ship it ugly in week one and use it daily.
Because a beautiful thing you haven't lived in is a guess. An ugly thing you've walked for a week is knowledge.
Empty states and error states go in the spec. They are not polish; they are the parts you meet first.
The practice
Take the thing you're building. Name the narrowest path that would count as 'it works'. Build only that. Use it tomorrow.
Depth teaches. Breadth postpones. Build the slice.
The build discipline that replaced breadth-first, after enough breadth-first failures. Read what it is →
← previousthe teachingsnext →
scroll to walk
1 / 9