NextTool

Diff Checker

How to use

Compares two blocks of code or text line by line and highlights exactly what was added, removed or left unchanged, handy for reviewing edits before you commit them. Paste the original in one box and the changed version in the other, and the differences are marked automatically.

Developer PopularLocal only
runs live, on-device
Compare two blocks of code or text line-by-line, entirely on-device
2 added · 2 removed
Original · 5 lines
Changed · 5 lines
Side-by-side diff
+2-2~2
1/1
OriginalChanged
1−function greet(name) {
1+function greet(name, greeting = "Hello") {
2− const msg = "Hello " + name;
2+ const msg = `${greeting} ${name}`;
3 console.log(msg);
3 console.log(msg);
4 return msg;
4 return msg;
5}
5}
When to use this
  • Reviewing a pull request line by line without pulling the branch locally
  • Comparing two versions of a config file before deploying a change
  • Sanity-checking an automated code transformation against the original file
  • Spotting exactly what changed between two saved drafts of a script

Free and private. Everything runs on your own device, with no account and no uploads.

Reviewing a pull request without a Git client handy, or comparing two versions of a config file before deploying, is much faster with a visual diff. This tool compares two blocks of code or text line by line and produces a color-coded diff showing exactly what was added, removed, or left unchanged, giving developers a quick way to sanity-check edits before committing them.

It primarily compares line by line, similar to a standard git diff, which makes it easy to spot which lines were added, removed or modified in code and config files.

Yes, paste the full contents of each file version into the two panels and the tool will compute the differences across the entire content.

By default, whitespace differences like extra spaces or indentation changes are treated as real changes; check for a whitespace-ignore option if you only care about content changes.

It is meant for quick ad hoc comparisons of pasted text rather than replacing git's full diff and merge tooling for an actual repository workflow.

How it works
  1. 1

    Paste the original version

    Add the first file or code block into the left panel.

  2. 2

    Paste the changed version

    Add the updated file or code block into the right panel.

  3. 3

    Compare

    Run the comparison to generate the line-by-line diff.

  4. 4

    Review the color-coded changes

    Added, removed and unchanged lines are marked in distinct colors.

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Read about this
Finding what changed between two versions of a document4 minHow diff tools work, and why they sometimes show the wrong change3 min
Pro tips
  • ·Paste full file contents on both sides for the clearest line-by-line comparison rather than partial snippets.
  • ·Check for a whitespace-ignore option if indentation-only changes are cluttering the diff with noise.
  • ·Use this for quick ad hoc comparisons, for an actual repository workflow, git diff and merge tooling still handle history and conflicts better.