For product owners

A design system helps a product look and work the same everywhere, so people only have to learn it once. It also speeds up delivery, because the common parts already exist and have been tested, and teams do not have to design and build the same thing again.

Accessibility is built into every part from the start and is not added at the end, and the design decisions are written down in one place so that they can be found and followed.

Principles explain how and why the system is designed. Foundations list the colours, type, spacing and layout that everything is built from, and Components show the parts that exist, from the smallest to whole page layouts. Pages show the parts working together with realistic content, and the version history says in plain words what has changed and why.

A good request explains what problem people have and how you know about it, where in the product it happens, what has already been tried with the existing parts, and how many places would use the change. That gives the design and development team what they need to judge whether the change belongs in the system.

A new component or colour has to be needed before it is added, because every addition must be learned, documented and maintained. If an existing part can do the job, the answer is usually to use it or to improve it.

Changes are checked against the design principles. They have to work for everyone, match between design and code, be really needed, use colours named by their job, and be explainable in plain words. Changes to a value, to how a component works, or to the folder structure are agreed before they are made, so that nothing surprising reaches the product.