Input validation: why it matters

When you build a product where users upload files and set publishing parameters, input validation becomes the first line of defense against failures.

We confirmed this in practice: most errors that reached application logic could have been caught earlier — at the level of checking file type, size, and correctness of time parameters.

The platforms we publish to have strict constraints. Video of a certain size, certain duration, certain codec. If we don't check this ourselves, the error will come from an external API and will be harder to interpret.

Boring work with a big practical payoff.