1. What does this tool do
This free online text diff checker shows what changed between two text inputs. Use it to compare two texts, diff two documents, or see text differences with word-level or line-level diff and clear highlighting of additions and deletions. Free and private—no sign-up, no upload; everything runs in your browser. Ideal for revisions, code/config comparison, contracts, or paste-from-anywhere comparison.
2. How to use it
Quick start: Paste the original text in one box and the revised in the other. Choose word-level or line-level, then view the diff with additions (e.g. green) and deletions (e.g. red). Copy or refine as needed.
- Enter or paste two texts — Put the first (e.g. original) in one box and the second (e.g. revised) in the other.
- Choose mode — Select word-level or line-level comparison depending on your need.
- View the diff — Additions and deletions are highlighted (e.g. green for new, red for removed). Scroll to review.
- Copy or refine — Use the result to document changes or paste into other tools.
3. How it works
The tool computes a diff (e.g. line-based or word-based) between the two strings. A diff algorithm (e.g. LCS-based) identifies added and removed segments. The result is rendered with inline or block highlighting. All processing is client-side in your browser; no text is sent to any server.
4. Use cases & examples
- Revisions — Compare two drafts of an essay or report.
- Code or config — See what changed between two snippets (use line-level for code).
- Contracts or policies — Highlight edits between versions.
- Paste from anywhere — Compare copied text from emails, docs, or logs.
Example
- Old: "The quick brown fox." New: "The fast brown fox." → "quick" deleted, "fast" added.
- Line diff: add or remove full lines to see paragraph-level changes.
5. Limitations & known constraints
- Browser memory — Very large documents (e.g. millions of characters) may slow or exceed practical limits.
- Plain text — The tool compares plain text; formatting (e.g. Word or PDF) is not interpreted.
- No merge — This is a comparison view only; it does not merge or resolve conflicts.