Text Diff Tool

• Word Diff compares token by token. A paragraph where one adjective changed shows just that adjective, so the surrounding sentence stays readable. Reach for it with prose, documentation, translations and marketing copy.
• Line Diff treats a whole line as the unit, so any edit marks the line as removed and re-added. That sounds coarser, and it is, but it matches how code, logs and configuration are actually reviewed: you want to know which lines moved, not which characters did.

Three states, and only two of them are coloured:

• Green is in the new text but not the original. It was added.
• Red is in the original but not the new text. It was removed.
• Unstyled text is identical in both and can be skimmed past.

A rewritten passage has no separate colour of its own. It appears as the old wording in red followed immediately by the new wording in green, because that is literally what happened to it.

Reviewing edits: comparing a draft against the version that came back from a colleague, an editor or a client, so you can see what they actually touched rather than rereading the whole thing.

Contracts and policies: checking a returned agreement against the copy you sent. A single reworded clause is easy to miss by eye and impossible to miss here.

Configuration drift: comparing the config on one machine against another when only one of them works. Line diff usually finds it in seconds.

Logs and output: putting a failing run beside a passing one to isolate the first line where they diverge.

Code review offline: comparing two snippets without creating a branch, a commit or a pull request.

• Normalise formatting first. If one side has been reindented or reformatted, every line reads as changed and the real edit is buried. Run both through the JSON Formatter or the Markdown Editor before comparing.
• Watch for invisible differences. Trailing whitespace and a switch between Windows and Unix line endings both count as changes, which is often the explanation when a diff claims everything changed and nothing looks different.
• Compare sections rather than whole documents when the files are large. A shorter diff is a diff you will actually read.

The comparison runs in your browser. Both texts stay in the tab, nothing is uploaded, and nothing survives closing the page. That matters more for this tool than for most: the things worth diffing tend to be contract drafts, production logs and unreleased code, which are exactly the things you would not want to paste into an online service.