Diff Checker | Compare Text & Code Side-by-Side
Compare two texts or codebases line-by-line or character-by-character with color-coded highlights for additions, deletions, and modifications. Switch between side-by-side and unified views, ignore whitespace noise, and selectively merge changes—all processed privately in your browser.
How to Use This Tool
- 1
Paste the original into Text 1 and the changed version into Text 2.
- 2
Choose Line mode for code or Character mode for prose.
- 3
Toggle Ignore whitespace to hide formatting-only differences.
- 4
Pick Side-by-side or Unified view for your workflow.
- 5
Review highlights and use Apply arrows to merge changes selectively.
Use Cases & Examples
Code Review & Version Control
Review changes before commits/PRs, focus on logic, and hide formatting noise with Ignore whitespace.
Document Revision & Version Comparison
Compare document drafts to track edits from collaborators with precise, inline character diffs.
Configuration File Comparison & Environment Sync
Detect drift across environments by diffing JSON, YAML, INI, and other config files.
Translation Quality Assurance & Localization
Verify translation completeness and consistency by comparing source and localized text.
Understanding Diff Algorithms and Text Comparison
A diff computes the minimal sequence of edits (insert, delete, replace) needed to transform text A into text B.
This tool implements a Myers-style shortest-edit-script with heuristics for near-linear performance on similar files.
Both line-level and character-level tokenization are supported; all processing is client-side for data privacy.
Frequently Asked Questions
Q.What's the difference between Line mode and Character mode?
A. Line mode compares whole lines (ideal for source code and logs). Character mode shows inline edits within a line (ideal for prose and precise edits).
Q.What does 'Ignore whitespace' do? When should I use it?
A. It treats spaces, tabs, and line breaks as equivalent, hiding formatting-only changes—useful after running prettiers, formatters, or line-ending normalization.
Q.Can I compare very large files? Are there size limits?
A. The comparison runs in browser memory. Small and medium files are instant; very large inputs depend on available RAM/CPU in your device.
Q.What diff algorithm is used? How does it work?
A. It uses the Myers shortest-edit-script algorithm—the same family of algorithms used by Git—to produce concise, human-readable diffs efficiently.
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