Utileno
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LOCAL TOOL · TEXT

Text Diff Checker

Paste two versions of a text and see exactly which lines were added, removed or changed.

How to use
  1. Paste the original text on the left and the new version on the right.
  2. Press Compare.
  3. Read the unified result: green lines were added, red lines were removed, unchanged lines stay plain.
Examples
Contract revision check
Paste last week’s version and today’s version of an agreement to instantly see every line the other side edited.
Config file drift
Compare the config from two servers to spot the one changed line causing different behavior.
Checking what changed in a contract draft
Two versions of a document that look identical usually differ in a few clauses. Pasting both sides shows exactly which lines were added, removed or altered, which is faster and more reliable than reading both in parallel — the eye skips over small changes precisely because the surrounding text is familiar.
Verifying a copy-paste worked
When moving configuration or a list between systems, comparing the source against what actually arrived catches truncation and encoding damage immediately. A silent difference at the end of a long block is the failure mode that manual checking misses most often.
Reviewing edits to your own writing
Comparing a draft against its revision shows the shape of the edit — whether you tightened throughout or rewrote one section. It also catches the paragraph you meant to restore and did not, which is hard to notice when you already know what the text is supposed to say.
Duplicate Line RemoverPaste a list, and repeated lines disappear — with control over case, whitespace and ordering.Word & Character CounterPaste or type text and get live character, word, line, paragraph and byte counts — nothing is uploaded.JSON Formatter & ValidatorFormat, validate and minify JSON without uploading it — your data stays in your browser.
FAQ
How does the comparison work?
The tool computes a longest-common-subsequence diff over lines — the same family of algorithm used by version control systems like Git — and shows the minimal set of added and removed lines.
What counts as a “changed” line?
When a removed line is directly followed by an added line, the pair is counted as one changed line — an edit in place rather than separate deletion and addition.
Does it compare characters within a line?
This tool compares whole lines, which keeps results fast and easy to read. A line with any change shows as removed + added.
Is there a size limit?
Texts of up to about 1,500 differing lines get an exact minimal diff. Beyond that, the differing middle section is shown as one replaced block so the page stays fast.
Are my documents uploaded?
No. The comparison runs entirely in your browser; neither text leaves your device.
Why does one changed word mark the whole line?
The comparison works line by line, so any difference within a line marks that line as changed. This keeps the output readable for prose and configuration alike. For a fine-grained view, break long paragraphs into shorter lines before comparing — one sentence per line is a common approach.
Do trailing spaces and line endings count as differences?
Yes. Invisible characters are still characters, and a file saved on Windows can differ from the same file saved elsewhere purely in line endings. When two texts look identical but every line shows as changed, invisible whitespace is almost always the reason.
Can I compare files rather than pasted text?
Paste the contents rather than uploading — nothing leaves your browser, which is the point. For text, configuration and code this works well. For binary formats such as a Word document, export to plain text first, since comparing the raw file bytes tells you nothing useful.