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Difference Checker

Compare two versions of text, code, or JSON and see exactly what changed. Diff by lines, words, or characters, ignore whitespace or case, and format JSON to reduce noise.

Original Text

Tip: Drag & drop a text-based file (TXT, JSON, XML, MD…) into this box.

Changed Text

Tip: Drag & drop a text-based file (TXT, JSON, XML, MD…) into this box.
Comparison Mode:

Highlighted Differences

Added: 41
Removed: 44
Unchanged: 0
This is the original line.
And another line.This is the changed line.
And a new line.
TL;DR — compare text or code online and highlight differences

Paste or upload two versions of your text or code, choose Characters, Words, or Lines, and instantly see what changed. Turn on JSON formatting or ignore whitespace to reduce noise, then copy or download the diff. Everything runs in your browser — no uploads, no tracking.

Difference Checker – Compare Two Texts, Code Files & JSON Online Free

Compare two versions of text, code, or JSON side by side and see exactly what changed. This free online diff checker highlights additions and removals by lines, words, or characters — no login required. Paste or upload your content and get instant, color-coded results in your browser.

When someone asks "What changed between these two files?", you shouldn’t have to squint at them line by line. This online difference checker works as a text compare tool, a code diff viewer, and a JSON diff checker in one clean interface.

Start by pasting or uploading your original text on the left and the revised version on the right. You can drop in anything that’s text-based: a Markdown article, a CSS file, a JSON config, SQL queries, API responses, or log output. Then choose how precise you want the comparison to be. Lines mode is ideal for documents, logs, and long blocks of code; Words mode helps you review copy edits in sentences; Characters mode shows every low-level change, down to swapped punctuation or stray spaces.

To cut down on "false positives," you can tune the diff with a few switches. Ignore whitespace hides changes that are only about spaces or tabs. Ignore case focuses on wording changes rather than capitalization. Trim lines strips stray whitespace at the beginning and end of each line before comparison. For JSON, turn on Pretty JSON to format each side automatically and enable Sort keys to neutralize key-order differences. That’s especially useful when you’re comparing API responses or config files where formatting shouldn’t count as a "real" change.

As you compare, the tool highlights insertions and deletions so you can scan through quickly. A live summary shows counts of added, removed, and unchanged characters, which is handy when you’re trying to understand how big a change really is. If you ever paste text into the wrong box, use the Swap button instead of re-copying everything.

Once you’re happy with the comparison, you can copy the diff to your clipboard or download it as a .txt file for code reviews, documentation, bug reports, or audit trails. It’s a simple way to attach "before vs after" context to commits, tickets, and emails.

Everything happens in your browser. The difference checker is 100% client-side, so your code, drafts, and logs are never uploaded or stored on a server. That makes it safe to use with private repos, internal documentation, or confidential data as long as you’re comfortable pasting it into your own browser.

Whether you’re a developer looking for a quick online diff checker, a writer comparing document versions, or an analyst verifying exported data, this tool keeps the focus on the differences that matter and gets out of your way everywhere else.

Common uses for a diff checker

  • Code review — compare two versions of a function, config file, or script to confirm exactly what changed before merging.
  • Document version comparison — check what was added or removed between two drafts of a report, contract, or article.
  • JSON API response comparison — compare API responses from two environments (staging vs. production) with Pretty JSON and Sort keys enabled to ignore formatting noise.
  • Detecting changes in exported data — diff two CSV or log exports to quickly spot rows that were added, removed, or modified.

Key features

  • Side-by-side online diff checker for text and code
  • Compare by characters, words, or lines depending on how detailed you need to be
  • Ignore whitespace and case, and trim each line to reduce noisy differences
  • Pretty-print JSON and optionally sort keys before comparing API responses or configs
  • Upload or drag-and-drop text files into each side for quick file comparison
  • Clear highlighting of additions, deletions, and unchanged segments with a live summary
  • One-click copy of the diff output and .txt download for sharing or archiving
  • Swap sides instantly without re-pasting content
  • 100% client-side diff checker — nothing leaves your device

Tips

  • Turn on Pretty JSON + Sort keys to compare JSON API responses without being distracted by indentation or key order.
  • For articles, documentation, and emails, Lines mode is easiest to skim; switch to Words when you’re reviewing fine-grained edits.
  • If the diff looks noisy, enable Ignore whitespace and Trim lines to hide changes caused only by spacing.
  • Use Ignore case when you care about wording changes but not capitalization, such as style tweaks in copy.
  • Clean or normalize messy input with the Text Cleaner tool before comparing logs or poorly formatted exports.

Frequently asked questions

Which file types can I compare?
You can compare most text formats: JSON, XML, HTML, CSS, JS/TS, SQL, YAML, CSV, Markdown, and plain text logs. Binary files like PDFs or images won’t work, but you can paste text extracted from them.
Is my text uploaded anywhere?
No. This difference checker is entirely browser-based. Your content is processed in memory on your device and never sent to a server.
Why do I see unexpected results in the diff?
Your diff is shaped by options like Ignore whitespace, Ignore case, Trim lines, and Pretty JSON. Try toggling these on or off to match how you want to treat spacing, capitalization, and formatting.
Can I compare large files?
It depends on your browser and device memory. For very large files, you may get better performance by comparing them in chunks or using a desktop diff tool alongside this online checker.
Does this handle HTML, SQL, or XML?
Yes. HTML, SQL, and XML are treated as plain text. For most code-like content, Lines or Words mode gives a clean view of changes.
How do I compare two text files online for free?
Paste the original text in the left panel and the revised text in the right panel. Choose Lines, Words, or Characters mode and the differences are highlighted instantly. No account or software needed.
How do I compare two JSON objects online?
Paste both JSON objects into the left and right panels, enable Pretty JSON and optionally Sort keys, then run the diff. This removes formatting noise so only real value changes are highlighted.
Can I compare code files online without installing software?
Yes. Paste or upload any text-based code file (JavaScript, TypeScript, Python, HTML, CSS, SQL) into each panel. Lines mode works best for code comparisons. Everything runs in your browser with no software to install.

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