Building Universes from Code: The Space Between What Was and What Is

Tim Ellis
Dec 17, 2025
2 min read

Updated: Dec 19, 2025

Series: The Journey from Legacy to Modern APIs - Part 2

A stylised, clay-like character with glasses stands between two contrasting digital worlds—warm orange light on one side and cool blue technology on the other—holding glowing golden cubes in their outstretched hand as particles and data fragments swirl around them, symbolising the power to build and connect different digital universes.

When there is no direct replacement for an old API, the difficulty isn’t technical alone - it’s conceptual.

The original system didn’t just provide functions. It provided meaning. A way of thinking about data, behaviour, and responsibility.

The new API offers something different. Not better or worse - just different.

Concepts have shifted. Responsibilities have moved. What was once implicit is now explicit. What was once central is now distributed across multiple services or layers.

And so the real challenge emerges in the space between the two.

You can’t simply map old calls to new ones. You have to understand why the original code existed in the first place. What problem it was solving. What assumptions it made about the world around it.

Only then can you begin to rebuild that intent using the tools of the modern system.

This process can feel unsettling. Entire sections of code must be dismantled, not because they are broken, but because the universe they belonged to no longer exists.

And yet, within this disruption lies opportunity.

In the final post, we’ll explore how this kind of forced evolution can lead not just to compatibility, but to clarity.