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Data Mobile Cloud
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Diff Viewer

Compare two blocks of text or code side by side. See line-by-line differences with character-level highlighting — nothing leaves your browser.

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Paste text in both panels to see the diff

Nothing is sent to the server — all processing happens in your browser.

What Is a Diff?

A diff(short for “difference”) is a comparison between two versions of a text. It shows which lines were added, which were removed, and which stayed the same — making it easy to see exactly what changed between an original and a modified version.

The unified diff format presents both versions in a single column, using + prefixes for added lines and -for removed lines. It's the format used by git diff and most version control systems. The side-by-side format places the two versions in adjacent columns, so you can visually align corresponding lines.

When to Use a Diff Tool

  • Configuration files:Compare server configs, YAML files, or environment variables before deploying changes. Spot unintended edits, missing keys, or formatting drift.
  • Code reviews:Paste the before and after versions of a file to see exactly what changed — without needing a Git repository or command-line access.
  • Troubleshooting:Compare error logs, API responses, or query outputs to identify what differs between a working and broken system.
  • Documentation edits:Review edits to markdown files, READMEs, or knowledge base articles before publishing.

Understanding Intra-Line Changes

Most diff tools stop at the line level: they tell you which lines changed, but not what changed within those lines. This tool goes further with intra-line highlighting — it analyses the specific words and characters that differ within each changed line, highlighting them so you can see at a glance whether a typo fix, a variable rename, or a value change is responsible.

For example, if the only change on a line is “port 80” becoming “port 443”, the surrounding text stays unhighlighted while just the changed portion is emphasised — saving you from scanning entire lines to find a single-character difference.

Frequently Asked Questions

Is my data sent to a server?
No. All diff computation runs entirely in your browser using JavaScript. Your text is never transmitted over the network.
What is the difference between unified and side-by-side view?
Unified view shows both versions in a single column with + and − prefixes, similar to git diff output. Side-by-side view places the original and modified versions in adjacent columns so you can visually compare corresponding lines.
What does character-level highlighting mean?
When a line has changed, the diff tool identifies the specific words or characters that differ within that line and highlights them with a stronger colour. This makes it easy to spot a single-word change or typo within a longer line.
Can I compare files with different line endings?
Yes. The tool normalises line endings during comparison, so files with mixed or different line-ending styles (LF vs CRLF) will still produce accurate diffs.
Is there a size limit?
The tool handles files of several thousand lines comfortably. Very large inputs (tens of thousands of lines) may slow down the browser but will still produce correct results.
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