Text Differ

Compare two pieces of text and see the differences highlighted. Useful for spotting changes and analyzing variations.

What is Text Differ?

A Text Differ (diff checker) is a tool that compares two versions of text side by side and visually highlights exactly what changed between them. The term 'diff' comes from the Unix diff command, a foundational tool in software development that has been in use since the 1970s. Modern diff tools are indispensable across many disciplines: developers use them to review code changes before committing to version control, writers use them to track revisions between drafts, system administrators use them to compare configuration files before and after changes, and data analysts use them to spot differences in exported reports or dataset snapshots. A diff operates at the line level—it identifies which lines were added, removed, or modified—and often at the word or character level within changed lines for fine-grained comparison. Additions are shown in green, deletions in red, and unchanged content appears in neutral color, making the changes immediately obvious at a glance. This eliminates the tedious and error-prone process of manually reading through two similar documents to find discrepancies. Whether you are comparing contract versions, JSON API responses, configuration file backups, translated documents, or two versions of a README file, a diff checker gives you an instant, accurate picture of every difference.

How to Use Text Differ

Paste the original or older version of your text into the left panel, and the modified or newer version into the right panel. Click the Compare button to compute the differences. Changed lines are highlighted: green for additions (content in the new version that wasn't in the original), red for deletions (content removed from the original), and unmarked for unchanged lines. The diff summary at the top shows the total number of added and removed lines at a glance. For code files, use the character-level diff mode to see exactly which words or characters changed within a line—particularly useful for spotting a renamed variable or a changed configuration value. Toggle the 'Ignore whitespace' option to skip differences caused only by spaces, tabs, or indentation—ideal when comparing code reformatted by different editors. Toggle 'Case-insensitive' to treat uppercase and lowercase letters as identical. The side-by-side and unified diff views are both available: side-by-side shows the two versions next to each other, while unified view shows changes inline as a traditional patch format.

FAQ

What is the difference between line-level and character-level diff?

Line-level diff (the default) identifies entire lines as added, removed, or changed. Character-level diff goes deeper and highlights the specific words or characters that changed within a modified line. Character-level is more precise and useful for code reviews where a single renamed variable or changed value matters, while line-level is faster for document-level comparisons.

Can I compare source code from different programming languages?

Yes. The diff tool works with any plain text input regardless of programming language or file format—JavaScript, Python, HTML, CSS, SQL, JSON, YAML, Markdown, XML, configuration files, and plain text documents all work the same way. The tool compares the raw text content, not language semantics, so it handles all formats equally well.

How do I compare two files?

Open both files in a text editor and copy the contents into the respective panels. Alternatively, if the files are code files, you can use your IDE's built-in diff viewer (VS Code, JetBrains) or git diff for version-controlled files. This web tool is best for quick ad-hoc comparisons without needing a local dev environment.

Is the comparison case-sensitive?

By default, yes—'Hello' and 'hello' are treated as different. Enable the 'Case-insensitive' toggle to treat uppercase and lowercase letters as identical. This is useful when comparing documents where capitalization varies inconsistently but the content is otherwise the same.

Can I compare JSON or XML to see structural differences?

Yes, paste the raw JSON or XML text into both panels. For the most meaningful results with JSON, format both sides with consistent indentation first using the JSON Formatter tool—this prevents false differences caused only by whitespace or key ordering variations. For true semantic JSON comparison, dedicated JSON diff tools that normalize key order are more reliable.