Text Diff Checker
Compare two texts and see exactly what changed — line by line and word by word, side-by-side or unified
About this ToolHow it works, benefits & use casesTap to collapse
When two versions of a file or snippet look almost identical, the Text Diff Checker shows you exactly what changed. Paste the original on the left and the modified text on the right (or load either side from a file), and it computes a proper Myers diff — the same algorithm Git uses — aligning lines correctly even when content is reordered or repeated, and highlighting the specific words that changed within each line. Choose a side-by-side split view or a stacked unified view, and turn on options to ignore case, ignore whitespace, trim lines, or skip blank-line changes. A live similarity percentage and add/remove/unchanged counts summarize the result. Export the comparison as a unified .diff patch, download it, or copy it as a fenced Markdown diff block. The comparison is captured in the page URL for sharing, and nothing you paste leaves your browser.
How to Use
- 1Paste or type the original text in the left "Original" panel and the changed text in the right "Modified" panel — or use the upload icon on either panel to load from a file.
- 2Optionally open "Comparison options" to ignore case, ignore whitespace, trim lines, or ignore blank-line changes.
- 3Click "Compare" (or press Cmd/Ctrl + Enter) to compute the diff; it also recomputes automatically a moment after you stop typing.
- 4Toggle between "Split" (side-by-side) and "Unified" (stacked) views, and read the added / removed / unchanged counts and similarity percentage.
- 5Export the result with "Copy .diff", "Download .diff", or "Copy as Markdown", or use "Swap sides" to reverse the comparison.
Key Benefits
- Myers (jsdiff) algorithm aligns reordered and repeated lines correctly
- Word-level highlighting shows exactly which words changed inside a line
- Split side-by-side and unified stacked views from the same comparison
- Ignore case, ignore whitespace, trim lines, and ignore blank lines
- Live similarity percentage plus added / removed / unchanged line counts
- Export as a unified .diff patch, download it, or copy as a Markdown diff block
- Share an exact comparison via URL; loads up to roughly 1 MB per side from a file
Common Use Cases
- Reviewing what changed between two versions of a config file or code snippet
- Comparing pasted log output or API responses to spot a single differing field
- Checking edits in a draft or document before committing them
- Generating a unified .diff patch to attach to a bug report or pull request
- Confirming two files are byte-identical apart from whitespace or line endings
Was this tool helpful?
Share Your Experience
Help others discover this tool!
Related tools
- Code Diff CheckerCompare and highlight code differences
- Merge Conflict ResolverVisualize and resolve Git merge conflicts
- Git Diff VisualizerVisualize Git diff output with syntax highlighting
- Regex TesterTest and debug regular expressions
- Bundle Analyzer VisualizerPaste a bundle file list to get a visual size treemap, gzip/brotli estimates, performance-budget pass/fail checks, and a build-vs-build diff of what grew or shrank
- Text to HexConvert text to hexadecimal
It uses jsdiff, a proven implementation of the Myers diff algorithm — the same family Git relies on. Unlike a naive position-by-position comparison, it backtracks to align lines correctly even when content is moved or repeated, and it produces an intra-line word diff so you see the precise words that changed.
Split view shows the original and modified text in two side-by-side columns, making it easy to scan additions and deletions in parallel. Unified view stacks everything in one column with removed and added lines interleaved, which is closer to a traditional patch. You can switch between them at any time without recomputing.