Diff Checker

Compare two blocks of text or code and review every line that changed.

Runs locally in your browser

Ignore whitespaceIgnore case

Original5 linesChanged5 lines

Unified diff

+3 added · −3 removed

1−const greet = (name) => {

2− return "Hello, " + name;

1+const greet = (name: string) => {

2+ return `Hello, ${name}!`;

33 };

5−greet("Ada");

5+console.log(greet("Ada"));

Complete tool guide

Diff Checker guide

The diff checker uses a line-by-line longest common subsequence comparison to expose additions, removals, and unchanged context.

Your input is processed in the current browser tab and is not sent to the application server.

Why use this tool?

Inspect or transform developer data without installing another utility.
Copy a clean result directly into code, a terminal, an API client, or documentation.
Keep routine developer work in one fast, consistent interface.

Common use cases

Reviewing a configuration change before deployment
Comparing API responses or generated output
Finding edits between two versions of prose or code

How to use it

1
Paste the earlier version into Original.
2
Paste the new version into Changed.
3
Adjust whitespace or case matching if needed.
4
Switch between unified and side-by-side views, then copy or download the diff.

Green lines

A plus sign marks a line that exists only in the changed version.

Red lines

A minus sign marks a line that exists only in the original version.

Comparison options

Ignoring whitespace or letter case changes what is considered equivalent without changing the source text.

Two review modes

Unified view shows a compact patch-style stream, while side-by-side view aligns original and changed lines in separate columns.

Practical tips for better results

Compare formatted inputs when structural changes matter.
Leave whitespace matching enabled when reviewing code indentation.
Use the downloaded .diff as a review artifact, not as an automatically applicable patch.

Frequently asked questions

Does the Diff Checker upload my data?

No. The transformation runs locally in your browser. Avoid pasting secrets into any tool you do not control, and clear the fields when using a shared device.

Can I use the result in production?

You can copy or download the result, but review it in the context of your application and run the project-specific tests or validation required by your workflow.

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