Why Notebooks Fail in Production

2025-01-15

Notebooks are one of the most powerful tools in modern technical work — but they are notorious for breaking down once they leave the research phase.

This post explains why, using concrete examples, and what a more robust notebook-first product model looks like.

The Promise of Notebooks

At their best, notebooks provide:

• Fast iteration
• Inline documentation
• Reproducible analysis
• A shared medium between roles

For a single researcher or developer, this is incredibly productive.

The problem is not notebooks themselves —
it’s how we try to operationalize them.

Where Things Go Wrong

Once notebooks move beyond a single author, several failure modes appear.

1. Hidden State

Cells can be executed out of order, producing results that cannot be reproduced from a clean run.

# This cell depends on prior hidden state
model.fit(X_train, y_train)