How do you use this tool?
- Paste or type your original text in the left panel.
- Paste your revised text in the right panel.
- Choose unified view (single column) or split view (side-by-side).
- Review highlighted changes: green for additions, red for deletions.
- Copy the diff output or export it as plain text.
What This Tool Does
This text diff tool accepts two blocks of text and produces a visual difference report: which lines were added, which were removed, and which stayed the same. It’s the browser equivalent of running diff file1.txt file2.txt in a terminal — no installation, no account, no upload.
How It Works
The tool applies a line-based LCS (Longest Common Subsequence) algorithm to find the shortest edit path between your two texts. Each line is classified as:
| Symbol | Color | Meaning |
|---|---|---|
+ | Green | Added in the revised version |
- | Red | Removed from the original |
| (none) | Gray | Unchanged in both versions |
For character-level changes within a line, the tool optionally highlights the exact words or characters that changed — useful for spotting single-word edits in long paragraphs.
What Are Common Use Cases?
Contract and document review. Legal teams and editors frequently receive “Track Changes” documents, but not all workflows support Word. Paste the old and new clause text to see exactly what changed — no formatting dependencies.
Code snippet comparison. When a colleague sends a revised function or config file in Slack, paste both versions here to see the exact delta before applying the change. Works for any language: Python, SQL, YAML, shell scripts.
Email and communication drafts. Collaborating on an important client email? Paste the two draft versions and confirm which sentences changed before sending.
Before/after SEO content comparison. Compare two versions of a web page’s body copy to verify that all agreed revisions were applied correctly — useful for agencies and content teams.
API response debugging. If an API starts returning different JSON, paste two response samples to isolate which fields changed. Combined with the JSON diff tool for structured output.
Academic writing. Students and researchers can compare draft versions of papers to ensure advisor feedback was fully incorporated.
What Output Formats Are Available?
The diff output can be read in two views:
- Unified view: A single scrollable list, additions and deletions interleaved. Mirrors the output of
git diff— familiar to developers. - Split view: Two columns side-by-side, with original on the left and revised on the right. Easier for prose review and non-technical users.
Frequently Asked Questions
Can I diff more than two versions? This tool compares exactly two inputs at a time. For multi-version history, use a version control system like Git, which stores every revision and lets you diff any two commits.
Why does the tool show the whole line as changed when only one word differs? At the line level, any change to a line marks the entire line as modified. Enable word-level or character-level highlighting in the settings panel to see the precise change within the line.
How does this compare to git diff?
Functionally identical for line-based text comparison. The main difference is that git diff operates on committed files, while this tool works on any text you paste — including text that has never been in a version control system.
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