Text Diff

About Text diff

The text diff tool compares two blocks of text line by line and marks what was added, removed or edited. Changed lines that pair up are also highlighted down to the individual characters. Use it to review edits to prose, config files, code or copied logs when you do not have version control handy.

How to use it

1. Paste the earlier version into Original and the later version into Modified. Each box also has a small clear button.
2. Optionally switch on Ignore whitespace, Ignore case, or both. Click Swap to exchange the two sides.
3. Read the summary badges, which give the number of lines added and lines removed, or say the files are identical.
4. Choose Side by side or Unified with the tabs above the results.

One edited line in a three-line text

Original: alpha, beta, gamma (one per line)
Modified: alpha, beta 2, gamma (one per line)

+1 line added, -1 line removed. Line 2 shows beta on the left and beta 2 on the right, with the added space and 2 highlighted at character level.

When to use it

• Checking what a client changed between two drafts of a contract paragraph.
• Comparing two versions of a configuration file from different servers.
• Verifying that a copy-edit only touched the sentences you meant it to.
• Confirming that two exported lists really are the same once formatting noise is ignored.

Questions about Text diff

Does the comparison work by line or by word?

By line first. Whole lines are matched, then when a removed line lines up with an added one, a character-level pass highlights the exact pieces that differ inside it.

What does Ignore whitespace cover?

It trims each line and collapses repeated spaces and tabs into one before comparing, so indentation changes stop counting as edits. The lines are still displayed with their original spacing.

Why is my final line flagged when the words are identical?

A missing newline at the very end of one side makes that last line differ from its twin. Add or remove the trailing line break so both texts end the same way.

Is there a size limit?

Each side is limited to 100,000 characters. Anything beyond that is cut off and a warning appears above the box. Results refresh about 200 milliseconds after you stop typing.

What is the difference between the two views?

Side by side aligns the original and modified lines in two columns. Unified puts every line in a single column, like a patch, with removed and added lines shaded differently.

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