Text Diff Checker

Spot changes between two files or snippets using a split-view diff with inline highlights and export options.

Updated Dec 06, 2025

Original

Modified

Quality gates

Compare text files before committing

Spot tiny changes in config files, JSON payloads, documentation, or release notes. The Diff Checker renders additions and deletions side-by-side, mirroring the Git workflow but without requiring a repository.

High-signal comparisons

Paste two snippets or drag entire files into the left and right panes. The diff engine highlights inserted, removed, and modified lines with colors borrowed from familiar Git tooling. Inline diff mode zeroes in on changed characters, which is perfect for spotting swapped flags or parameter mistakes.

Toggle whitespace sensitivity, wrap long lines, or collapse matching sections to focus on what changed. Copying the entire diff or exporting a shareable link takes one click, making asynchronous reviews painless.

Language-agnostic
Designed for JSON, YAML, Markdown, SQL, or logs—anything rendered as text benefits from the diff visualization.
Offline-friendly
Because diffs run client-side, you can compare secrets or proprietary docs without uploading them to a cloud service.

Use it across teams

Writers track edits to blog posts, support reps compare customer exports, and SREs validate configuration drift before rolling back. Diff Checker complements GitHub reviews by covering cases where you only have final files, not repositories.

Pairs well with other FreeTools.run utilities: format JSON first, then diff it; convert curl commands, then diff the generated code against existing SDK samples.

Quick approvals
Annotate diffs with context and paste them into PR descriptions or incident retrospectives.
Release audits
Verify changelog entries or license updates line-by-line before publishing a release.

Great for

Config drift detection

Compare exported Kubernetes manifests or Terraform plans to spot unexpected toggles.

Localization reviews

Ensure translators changed only copy, not placeholders or Markdown structure.

API schema updates

Paste JSON schemas from staging vs. production to confirm shape changes before deploying clients.

Legal & policy redlines

Highlight exactly what changed in contracts without exposing them to third-party diffing services.

Next step

Need to reformat before diffing?

Use the JSON Formatter to normalize indentation, then bring the cleaned payloads back to Diff Checker for a noise-free comparison.

Open JSON Formatter

Popular combinations

Audit with Diff Checker
Compare Text Diff Checker output with previous revisions to avoid regressions.
Share via QR Code Generator
Turn sanitized payloads into QR codes for offline reviews.

Frequently asked questions

How do I compare two text files?

Simply paste your original text into the left pane and the modified text into the right pane. The tool will automatically highlight the differences. You can also drag and drop files directly into the editor.

Is my data secure?

Yes. The diff comparison happens entirely in your browser using JavaScript. We do not upload your files or text to any server, so your sensitive data remains private.

What file formats are supported?

The Diff Checker works with any plain text format, including code (JavaScript, Python, HTML, CSS), configuration files (JSON, YAML, XML), and standard documents (Markdown, TXT).

Can I ignore whitespace changes?

Yes. You can toggle options to ignore leading/trailing whitespace or empty lines, allowing you to focus on meaningful content changes rather than formatting differences.

What is the difference between Inline and Split view?

Split view shows the two files side-by-side, which is great for understanding context. Inline view merges them into a single document with additions and deletions marked, which is often more compact for reviewing small changes.

How to use Text Diff Checker

Follow these four quick steps to compare revisions side-by-side right inside your browser—no downloads, no accounts, and no data leaving the FreeTools.run sandbox.

Step 1: Load your source data
Paste text, drag a file, or start with our curated sample to understand how the diff workflow behaves with real inputs.
Step 2: Adjust tool options
Toggle presets, update formatting rules, or choose export preferences. All controls update in real time so you can preview the effect before committing.
Step 3: Review the live preview
Use the split-pane preview, inline validation, or diff output to confirm the transformation looks correct before you copy anything back into your project.
Step 4: Export or chain another tool
Copy the result, download a file, or jump into a related FreeTools.run utility (like Diff Checker or the QR Code Generator) to continue the workflow without leaving the browser.