Spike solution is a short, throwaway experiment written to explore a technical question or reduce uncertainty. A spike answers a specific question: can we use this API fast enough, how hard is porting to Rust, which JSON library handles these edge cases.

Spike code written under speed-of-exploration constraints accumulates technical debt and should not become production code. Building on spike code leaves you with production code that was never designed for correctness or maintainability.

Spikes are time-boxed to force a conclusion. A spike running three days without a clear answer is a project, not a spike. The deliverable is knowledge and a written recommendation, not a feature. From Extreme programming.