🔄 Inline Text Diff

Inline diff shows both versions in a single flow — deleted text marked in red, added text in green, all in one column. This is ideal for prose comparisons where you want to see the exact word or character changes in context without switching eyes between two panels. Side-by-side diff shows the two versions in parallel columns — better for code comparisons where line structure matters and you want to see unchanged context lines clearly. For comparing blog post revisions, API response text changes, or documentation edits: inline diff is more intuitive. For comparing code files: side-by-side is the standard (see the Diff Checker tool on this site).

Word-level diff identifies which words were added or removed between two texts — the granularity is whole words separated by spaces. Character-level diff goes deeper, highlighting the specific characters within changed words. Example: changing 'colour' to 'color' in word-level diff shows the entire word 'colour' deleted and 'color' added. In character-level diff, only 'ou' → 'o' is highlighted as changed. Character-level is more precise and shows smaller changes clearly. Word-level is cleaner for documents with many small word substitutions.

This tool uses the Myers diff algorithm (1986) — the same algorithm used by git diff, GNU diff, and most diff tools. Myers finds the shortest edit script (minimum number of insertions and deletions) to transform one text into the other. For word-level diffing, the algorithm is applied to sequences of words rather than characters. When multiple minimum-distance solutions exist (tie-breaking), different implementations may show different diffs that are equally valid — this is why the same two texts can produce visually different diffs in different tools.

For structural JSON comparison: format both with the JSON Formatter first (ensure consistent indentation), then paste into this tool. Formatted JSON diffs show you exactly which values changed. For semantic JSON comparison (ignoring key order, which is meaningless in JSON objects): a specialized JSON diff tool is better. Diffing unformatted JSON against formatted JSON shows every character as changed — always normalize format before comparing. This inline tool is best for prose and text content; use the Diff Checker tool on this site for code and structured data comparisons.

Editorial review: showing an author exactly which words their editor changed in a document. Translation QA: comparing original text against back-translated text to identify semantic shifts. Content moderation: comparing submitted content against a policy document to identify differences. Version comparison: showing users what changed between two versions of a terms of service or policy document. API response monitoring: alerting when a third-party API response changes in unexpected ways. Content deduplication: verifying that similar articles are not too close to each other.

Whitespace-only differences (extra spaces, tabs, line endings) often produce noisy diffs that obscure real content changes. Enable 'ignore whitespace' mode to see only semantic content differences. This is especially important when comparing text from different sources: a document pasted from Word (CRLF line endings) versus text from a Unix editor (LF) appears completely different at the character level without whitespace normalization. Normalize line endings first by converting CRLF to LF before comparison.

The Diff Checker shows side-by-side line-level diffs — better for code comparisons. The Duplicate Remover finds repeated lines within a single document. The Word Counter measures the size of each version before comparison. The Regex Tester can find specific patterns that differ between two texts. The JSON Formatter normalizes JSON for clean diffing. All are in the Dev Tools section.