Firecasting

Problem

Most financial planning tools are either too generic or too complicated for quick scenario testing.

I wanted a simulator where I could change a few assumptions and immediately see how the long-term trajectory changed.

Approach

The core model separates assumptions from rendering so the same scenario logic can support different UI views.

• Keep scenario inputs explicit and versionable.
• Make simulation output deterministic for the same seed and assumptions.
• Prefer understandable math over black-box prediction.

Outcome

The project became a practical playground for architecture decisions around domain boundaries, data contracts, and incremental delivery.

It also reinforced how useful a clear domain model is before polishing UI interactions.