Validation
Noun · Development
Definitions
The process of checking that data conforms to expected rules — such as type, format, range, and business constraints — before it is accepted for processing or storage. Validation should occur at system boundaries (API inputs, form submissions, file uploads) and is a first line of defense against injection attacks and data corruption.
In plain English: Checking that incoming data meets the expected rules (like a valid email format or a positive number) before the system accepts and uses it.
Example: "Server-side validation caught that someone was submitting negative prices through a modified API request — client-side checks alone would have missed it."