Diff checker — compare two texts or code side by side
A diff checker compares two blocks of text or code and highlights exactly what changed — the added, removed and edited lines — side by side. Carbide's diff checker does this instantly in your browser: paste the old version on the left, the new one on the right, and the differences light up. Nothing is uploaded.
That last part is the whole point for anything sensitive. A contract revision, a private code snippet or two versions of a translation should not be sent to someone else's server just so you can spot the differences. Here is how it works and where it helps.
How to compare two texts and read the result
Comparing two versions takes three steps in the diff checker: paste the original text into the left pane, paste the changed text into the right pane, and read the highlighted result. Added lines are marked in one color, removed lines in another, and edited lines show both sides so you can see the before and after at a glance.
The expected result is a line-by-line map of every change, with unchanged lines kept in place for context. That makes it easy to answer the question you actually have — "what did they change in this document?" — without re-reading the whole thing. It works the same whether you paste a paragraph, a full article or a code file.
Is my text uploaded anywhere?
No. The diff checker runs the comparison entirely in your browser — both texts are read and compared on your own device, and neither one is sent to a server. This is the honest differentiator: several popular diff sites transmit your text to their servers to compute the difference, and some only promise local processing behind a paid desktop app.
Because nothing leaves the browser, the tool is safe for the material people most often need to compare: legal drafts, unreleased code, personal messages and confidential reports. There is no account, no history stored online and no retention window you can't see. Close the tab and the text is gone.
Comparing code and JSON before a deploy
For developers, a diff is the fastest way to confirm what a change actually touched. Paste the current file and the proposed one into the diff checker and you get a clean review of every added or removed line before you commit or ship — useful when a pull request is noisy or a config file was edited by hand.
Comparing two API payloads or config blobs is easier if you tidy them first. Run each one through the JSON formatter to pretty-print and sort keys, then diff the two formatted versions — reordered keys stop showing up as false changes, so the diff shows only the values that really differ. The same trick works for XML responses.
Contracts, translations and everyday text work
A diff checker is not just a developer tool. Legal and admin teams use it to catch every edit between two versions of a contract or policy — the clause someone quietly reworded is impossible to miss when it's highlighted. Editors and translators compare a draft against its revision to see what a reviewer changed without scrolling through both files.
It also handles Arabic and mixed right-to-left text correctly, so comparing two versions of an Arabic document works the same as English. When you just need to count or reshape text rather than compare it, the character counter tallies words and characters, and the text converter changes case or reverses a string.
Side-by-side vs inline word-level diffs
There are two useful ways to view a difference. A side-by-side (split) view puts the two versions in parallel columns and is best for reading whole documents — your eye tracks each version down its own side. An inline view stacks the changes in one column, which is compact and good for short snippets or a quick scan.
For small edits, a word-level or character-level highlight is clearer than marking the entire line as changed: instead of flagging a full sentence, it points at the single word or number that moved. The diff checker highlights changes at the line level with the exact edits marked, so a one-character fix stands out instead of hiding inside a "changed" line.
Frequently asked questions
Is my text uploaded when I compare it?
No. The diff checker compares both texts entirely in your browser — nothing is uploaded to a server. That makes it safe for contracts, private code and confidential documents.
Is this diff checker free?
Yes. Comparing text or code is free with no limits, no sign-up and no watermark. There is no paid tier that unlocks a real feature — the full side-by-side comparison is available to everyone.
Does it work with Arabic and right-to-left text?
Yes. The diff checker compares Arabic and mixed RTL text correctly, so you can spot changes between two versions of an Arabic document just as you would with English.
Can I compare code or JSON files?
Yes. Paste both versions to diff any code. For JSON or config, format each side first with the JSON formatter so reordered keys don't show as false changes, then compare the tidied versions.
What's the difference between a side-by-side and an inline diff?
A side-by-side diff shows the two versions in parallel columns, best for reading full documents. An inline diff stacks the changes in one column, which is more compact for short snippets or a quick review.
A diff checker turns "something changed" into "here is exactly what changed". Start with the diff checker for contracts, translations or code reviews, and pair it with the JSON formatter when you need to compare payloads cleanly — free, private and entirely in your browser.