If there is one place where most system design mistakes begin, it’s here:

Designing without fully understanding the problem.

It sounds obvious, but in practice, this is exactly what happens.

We hear a problem statement and immediately start thinking about classes, APIs, or databases.

The result?

We end up solving the wrong problem very efficiently.

Why requirements matter more than design

Imagine building a food delivery system.

If you assume:

users can pre-schedule orders

restaurants can reject orders

delivery must happen within 30 minutes

…but none of these were actual requirements,

then your entire design is based on assumptions, not reality.

And once design is wrong, everything built on top of it will also be wrong.

The three layers of understanding

Before you design anything, you need clarity across three dimensions.

1.…