Case Insensitive Text Compare

Check whether two texts are equivalent after locale-aware case normalization and inspect remaining differences.

Original text

Modified text

——

Comparison runs locally in your browser. Interactive diff uses a bounded token count to avoid locking the page on extremely large inputs.

Case-folded equivalence is separated from raw equality

The tool reports whether text is exactly equal and whether it becomes equivalent only after locale-aware case normalization, avoiding an ambiguous single “same/different” result.

Usage notes optional

Case-insensitive is not the same as Unicode normalization

Two strings can look equivalent while using different composed or decomposed Unicode sequences. Case folding answers a capitalization question; normalization, locale-specific casing, whitespace rules, and punctuation handling are separate choices that should be made explicitly.

Keep raw equality visible when data integrity matters

For identifiers, hashes, filenames, source code, and protocol values, changing case may change meaning. Use case-insensitive comparison only when the destination rule truly ignores case, and keep the original strings available for an exact comparison.

Locale rules can change what “same case” means

Simple lowercase comparison is useful for many English-like identifiers, but language-specific casing such as Turkish dotted and dotless I can produce different results under locale-aware rules. If the comparison controls login names, database keys, or deduplication, use the exact normalization and locale policy of the destination system rather than assuming browser default case folding matches production.

Decide whether spaces and punctuation are significant

Case folding does not remove leading spaces, repeated whitespace, hyphens, punctuation, or invisible Unicode characters. If your application ignores any of those, normalize them explicitly before comparing and document the rule so a later system does not apply a different equivalence test.