Bytelify

Code Compare Tool

Compare two blocks of code line by line and see exactly what changed, in any language.

Runs in your browser, nothing sent
code-compare-tool

Compared line by line, live as you type, in any language — entirely in your browser.

Need the opposite? Text Compare

What is Code Compare Tool?

Paste two versions of a code snippet, in any language, and see a line-by-line diff, added lines in green, removed lines in red. Useful for a quick before/after comparison without opening a full diff tool. Because the comparison is plain line-by-line text matching rather than a language parser, it works identically for JavaScript, Python, config files, or any other text-based format. There's no language selector to get wrong. Everything runs in your browser, so pasted code snippets, including ones you'd rather not paste into a third-party diff service, never leave your machine.

How to Use the Code Compare Tool

  1. 1

    Paste the Original Code: Enter the original version in the left panel.

  2. 2

    Paste the Changed Code: Enter the updated version in the right panel.

  3. 3

    Read the Diff Instantly: Added, removed, and character-level changed lines are highlighted automatically.

How It Works

The two inputs are split into lines and compared using a line-based diff algorithm: each line in the left panel is matched against the closest corresponding line in the right panel, rather than comparing the whole text as one block, and shown side by side with matching line numbers. A line present only on the left is marked as removed (red); a line present only on the right is marked as added (green); a line found unchanged in both stays neutral. When a line on one side is replaced by a line on the other, the exact characters that changed within it are highlighted too, so a one-word edit inside a long line doesn't just flag the whole line — it shows you precisely what moved.

Example

-0 removed

+1 added

1function add(a, b) {
2 return a + b;
3}
1function add(a, b) {
2 console.log('adding', a, b);
3 return a + b;
4}

A console.log(...) call added in the middle of the function — the surrounding lines stay unchanged, only the new line is flagged.

Common Use Cases

  • Comparing two versions of a function before and after a refactor to confirm only the intended lines changed.

  • Diffing two API responses or config files (e.g. a `.env.example` against a teammate's `.env`) to spot drift.

  • Reviewing a code snippet pasted from a pull request against your local copy without switching to a full IDE diff view.

FAQs

Frequently Asked Questions

Common questions about Code Compare Tool.

No. This is a plain line-by-line text diff, which works for any language since it doesn't need to parse the code, but it also won't recognize that a reformatted (but logically identical) block is "the same." Changed lines do get character-level highlighting within the line, but that's still plain text matching, not syntax awareness.

No, the diff is computed entirely in your browser using JavaScript. Nothing you paste is transmitted anywhere.

Yes, by default. A line that only differs in indentation or trailing whitespace is still flagged as changed, since the comparison is exact text matching rather than a syntax-aware diff.

Yes, Bytelify's Code Compare Tool is free with no account or sign-up required.