Diffchecker alternative that keeps your text on your device
Diffchecker is a popular site for comparing two blocks of text, and it also handles files and other formats. It is quick and the output is easy to read. The reasons people look for a Diffchecker alternative are mostly about where the text goes: contracts, source code and drafts are often confidential, and pasting them into a website is a decision worth pausing on.
MergeDoc's Text Diff compares two pieces of text in your browser and highlights added and removed words. Compare PDF does the same for the text inside two PDFs. Nothing is stored or transmitted.
Our diff is deliberately simple, so here is where it falls short.
Why people look for a Diffchecker alternative
Pasting confidential text into a website
Legal drafts, internal documents and proprietary code are awkward to paste into a third-party service. A local tool keeps them on your machine.
Shareable links you do not need
Some diff sites are built around saving and sharing results. If you only want to see the changes once, a page that stores nothing is a feature.
Comparing two PDFs
Many people end up diffing PDFs by copying text out by hand. Compare PDFs extracts the text for you and diffs it.
Quick checks on your own drafts
Comparing two versions of an essay, a cover letter or a policy usually takes seconds. You do not need accounts, saved history or sharing for that, only a clear view of what changed between the two versions.
Spotting silent edits
A counterparty might return a contract with small wording changes that are easy to miss when you read quickly. A word-level diff puts every added or removed word on screen, which is faster and more reliable than careful reading alone.
Diffchecker vs MergeDoc, side by side
| Diffchecker | MergeDoc | |
|---|---|---|
| Where your text goes | Sent to their servers for comparison; saved diffs are a feature of the service. | Compared in your browser. Nothing is stored or sent. |
| Sign-up | Basic comparison typically works without an account; saving and teams features tie to one. | None. |
| Usage limits | Free use typically has caps on input size or features; check their current terms. | None from us; large inputs depend on your device. |
| Watermark / ads | Free version typically shows ads. | No watermark. The site may show ads. |
| Diff granularity | Line-level and character-level views, plus syntax awareness for code. | Word-level diff only. |
| Offline use | Needs a connection for the web version; desktop app is available. | Comparison needs no network once the page has loaded. |
| PDF comparison | Compares PDFs, including a visual mode in paid tiers. | Compares extracted text from two PDFs. No visual or layout diff. |
| Speed on large inputs | Server-side work can handle big inputs. | Our word diff is O(n by m), fine for page-sized text, slow for whole books. |
When Diffchecker is still the better pick
- •You want a line-by-line, side-by-side code diff with syntax highlighting.
- •You need to share a diff with a colleague through a link.
- •You want to compare images, spreadsheets or folders, which we do not support.
- •You are comparing very large documents, where a server-side diff copes better than our in-browser algorithm.
How to switch in a few steps
- 1.
Open Text Diff, paste the original on one side and the revised text on the other.
- 2.
Read the highlighted additions and removals. Nothing needs to be saved or submitted.
- 3.
For documents, use Compare PDFs to diff the text of two PDF files.
Tools covered
Read next
Compare Two PDFs and Find Every Changed Word
Compare two PDFs for differences in your browser. See added and removed words highlighted, and learn what a text diff can and cannot catch.
Why Client-Side Tools Matter: Keep Files on Your Device
Most online file tools upload your data to a server. Here is why many tasks do not need that, and the honest trade-offs of doing it locally.
Is It Safe to Upload Confidential PDFs to Online Tools?
What happens to a PDF you upload to a free online tool, which risks are real, and how to process contracts and IDs without uploading them at all.
Other alternatives
Frequently asked questions
- Is there a Diffchecker alternative that does not upload text?
- Yes. MergeDoc's Text Diff runs in your browser and does not store or transmit what you paste.
- Can I compare code with it?
- You can, but the diff is word-level without syntax highlighting. A code-focused diff tool will read better for large changes.
- How do I compare two PDF files?
- Use [Compare PDFs](/compare-pdf). It extracts text from both files and shows word changes. For method details see [compare two PDFs and find differences](/blog/compare-two-pdfs-find-differences).
- Will it detect formatting changes?
- No. It compares words only, so font, layout and image changes are invisible to it.
- Is there a size limit?
- We set none, but the algorithm is quadratic in word count, so very long inputs will be slow.
- Can I save or share a comparison?
- No. Results exist only on your screen. Copy what you need before closing the tab.
- Does it ignore whitespace or case?
- No. It splits text into words and compares them as written, so capitalisation differences count as changes.
Diffchecker is a trademark of its owner and is named here only for comparison. MergeDoc is not affiliated with or endorsed by Diffchecker. Check their current terms for the latest details.