A Diffchecker alternative for legal text
Diffchecker is a general comparison tool and does far more formats than this one. The differences that matter for contract text are narrower than that, and worth stating precisely.
What Diffchecker is
Diffchecker is a general-purpose comparison tool. It compares text, and depending on the version, files, PDFs, images, spreadsheets and folders. It is widely used, it is good at what it does, and if you need to compare two spreadsheets or two images this page is not going to be useful to you.
It is built for everybody — developers, writers, analysts, lawyers — which is a strength and is also the reason a tool built for one of those groups can differ usefully. What follows is about contract text specifically, and it is a narrow set of differences rather than a long one.
The differences that matter
Legal marking conventions. Redline Pad marks insertions underlined and deletions struck through in place, the way a redline has looked since it was done in red pen. Nothing is hidden, collapsed or moved to a margin. General comparison tools more often use coloured blocks, line numbers or side-by-side columns, which are the right conventions for code and are not what a reader of contracts expects.
Formatting from Word and Outlook. Text pasted out of a document arrives with bold, italic and lists intact, and those are compared: a defined term that lost its emphasis is reported as a formatting change rather than passing unnoticed. Tools that compare plain text discard that on the way in.
Where the text goes. The comparison here runs inside your browser. There is no upload, and the page is served with a Content-Security-Policy that forbids it from contacting any other origin, which you can verify in your own developer tools. Online comparison tools generally send what you paste to a server to be compared — reasonably, since that is how most of them work. Diffchecker's own documentation is the place to check what its various versions do, and it does offer a desktop application that works offline. If you are pasting a client's clause, that question is worth asking of any tool, this one included.
Copying it back. The redline copies as formatted text that pastes into Outlook, Gmail or Word with the strike-through and underline intact, plus a clean revised version, a Markdown version and a plain-text version with markers.
Side by side
| Diffchecker | Redline Pad | |
|---|---|---|
| Compares | Text, and depending on version files, PDFs, images, spreadsheets, folders | Text pasted into two panes, with its inline formatting |
| Marking | General-purpose comparison conventions | Legal redline conventions: underline and strike-through in place |
| Accounts | Free use without one; paid tiers available | None, and no paid tier |
| Where it runs | Online, with a desktop application also available — check their documentation for what each does | In your browser, verifiably |
| Breadth | Much wider than this | A clause or a paragraph, and nothing else |
Which to use
Use Diffchecker when you need the breadth: two spreadsheets, two PDFs, two images, a folder of files, or a comparison of anything that is not prose. Nothing here does any of that.
Use this when what you are comparing is contract prose, you want it marked the way a redline is marked, and you want the answer without your text going anywhere. That is a narrow case. It also happens several times a day in a drafting practice.