How to Validate Text with Regex

Step-by-step

1. Define exactly what is allowed.
2. Create a pattern for the required structure.
3. Test valid examples.
4. Test invalid and boundary examples.
5. Apply additional application-level validation where regex alone is not sufficient.

Regex is not always enough

Some values require parsing, semantic validation, database checks, or application-specific rules beyond a regular expression.

Anchor your intended input

When validating an entire field, consider whether the expression should match the whole value rather than only a substring.