Text Diff Tool
Compare two blocks of text and see the differences highlighted line by line.
Original
Modified
Usage Tips
- Side by Side: Shows original and modified text in parallel columns. Modified lines show character-level changes highlighted.
- Inline: Shows all changes in a single unified view with line prefixes (+ for added, - for removed).
- Ignore whitespace: Trims leading/trailing spaces before comparing — useful for indentation changes.
- Ignore case: Compares text case-insensitively — useful for case-only changes.
- Share: Copies a shareable URL with the current inputs pre-filled (up to 5 KB).
- Collapse: Long unchanged sections can be collapsed — click the divider to expand/collapse.
About Text Comparison
A text diff tool compares two blocks of text line by line and highlights the differences—added lines (shown in green), removed lines (shown in red), and unchanged lines (shown in white). This visual comparison is built on the Longest Common Subsequence (LCS) algorithm, the same core technology that powers Git's diff command, making it an industry-standard approach for identifying changes between document versions. Whether you're reviewing edits in a manuscript, comparing configuration file versions, or spotting differences in API responses, a text diff tool eliminates the tedious manual scanning and presents changes in a clear, structured format that makes it easy to understand exactly what changed and why.
Text diff tools are essential in software development workflows, documentation management, and compliance work. When code reviews happen in pull requests, diffs show the delta between branches. When legal teams audit contract changes, diffs highlight modifications. When DevOps engineers troubleshoot config management, diffs explain what changed between environments. By visualizing changes at the line and character level, diff tools reduce review time, catch unintended modifications, and serve as audit trails for accountability.
Common Use Cases
- Comparing document versions: Review revisions of articles, reports, or specifications to identify what was edited, removed, or added in each version.
- Reviewing code changes: Understand pull request changes or compare different branches without cloning repos—useful for quick assessment of merge requests.
- Spotting differences in config files: Identify configuration changes across environment deployments (dev, staging, production) or infrastructure code commits.
- Comparing API responses: Debug API issues by comparing successful vs. failed response payloads, or validate response format changes after API updates.
How to Use This Tool
- Paste both texts: Enter the original text in the left panel and the modified text in the right panel.
- Choose view mode: Select "Side by Side" to see original and modified in parallel columns, or "Inline" for a unified view with + and - prefixes.
- Configure options: Toggle "Ignore whitespace" to normalize leading/trailing spaces before comparison, or "Ignore case" for case-insensitive matching.
Features
Dual View Modes
Side-by-side view shows original and modified in parallel for easy visual comparison; inline view displays unified diff with + and - prefixes.
Line and Character-Level Highlighting
Line-level highlighting (green/red/white) identifies which lines changed, while character-level highlighting within modified lines pinpoints exact word-level edits.
Flexible Matching Options
Ignore whitespace sensitivity (for indentation-only changes) or case sensitivity (for capitalization-only edits) to focus on meaningful differences.
Diff Statistics and Sharing
View change counts (added, removed, modified, unchanged) and share diffs via URL with state pre-filled for collaboration without copy-paste.
Frequently Asked Questions
What is the difference between line diff and character diff?
Line-level diff shows which entire lines were added, removed, or modified (green, red, or yellow backgrounds). Character-level diff narrows down further by highlighting specific words or characters that changed within a modified line, reducing noise when only parts of lines are edited.
How is this different from JSON Comparator?
Text Diff compares arbitrary text (documents, config files, API responses, code). JSON Comparator is specialized for JSON objects with semantic awareness—it understands JSON structure, sorts keys, and ignores whitespace meaningfully. Use Text Diff for general text; use JSON Comparator for structured data.
Can I compare very large texts?
This tool works best with texts up to several MB. For massive files (100MB+), processing may slow down as the LCS algorithm is O(n*m) in time complexity. For very large diffs, specialized tools like Git or command-line diff are more performant.
Does this tool show moved blocks?
No, the LCS algorithm detects line additions and deletions but not moves or renames (where lines shift position). If a paragraph moves from line 10 to line 50, it appears as a deletion and an addition. Advanced diff tools like Git's move detection use heuristics for this.