Developer & data utilities
Text & JSON Diff Checker
Compare two texts or JSON objects line-by-line and highlight differences.
Run Text & JSON Diff Checker online
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Enable JavaScript to use the interactive tool. Read the instructions, limitations and FAQs below before starting.
The Text & JSON Diff Checker compares two blocks of text or JSON data line by line, highlighting exactly what changed between two versions. Whether you're comparing code, documents, configuration files, or API responses, this tool instantly shows additions (green), removals (red), and unchanged lines — exactly like a git diff.
Unlike most online diff tools that upload your data to servers, this diff checker processes everything in your browser. This matters when you're comparing sensitive data: source code with API keys, configuration files with passwords, legal documents, or personal data. The comparison algorithm uses a line-by-line approach that correctly identifies moved blocks and changed lines.
JSON comparison is particularly useful for API developers — paste two JSON API responses to see exactly which fields changed between versions. The tool also handles minified JSON gracefully. For code review workflows, use this alongside your code editor to spot differences before committing, or to compare two versions of a config file across environments.
How to use this utility
- Use the controls below—paste text, pick files, or adjust options as described on the tool.
- Click the main action button. Processing runs in your browser on this device.
- Download or copy the output. Check the processing note for any external services used by this operation.
Common use cases
- Comparing two versions of a JSON API response to find changed fields
- Spotting differences between production and staging configuration files
- Reviewing document edits before finalizing a contract or report
- Checking what changed in a downloaded file vs your previous version
- Comparing CSV exports to find data discrepancies
Tips for best results
- 1Paste JSON and use the JSON formatter first to pretty-print, then compare for better line-level diffs
- 2For long files, use browser search (Ctrl+F) to jump to the first diff
- 3The tool treats each line as a unit — for character-level diffs, split text on spaces first
- 4Use 'Original' for the baseline and 'Changed' for the modified version for intuitive coloring
- 5For code diffs with indentation changes, strip trailing whitespace before comparing
Frequently asked questions
- Is Konnect2Tools free?
- Yes. These in-browser tools are completely free to use with no account required for core functionality.
- Do my files leave my device?
- Browser document operations run locally, except where the operation uses an external service, such as AI summarisation. Read the processing note before using sensitive inputs.
- Is the Text & JSON Diff Checker tool safe to use?
- Local operations process document content on your device. External-service operations may send inputs as described in the processing note. Keep originals and inspect the output.
- Does this tool send my text to any server?
- No. The entire diff algorithm runs in JavaScript in your browser. Your text, JSON, or code never leaves your device. This makes it safe to compare sensitive configuration files, credentials (though we recommend removing sensitive values first), legal documents, and personal data.
- Can I compare JSON with different key ordering?
- The current tool does line-by-line text comparison, so JSON with different key orders will show differences even if the data is semantically equal. To compare JSON semantically regardless of key order, use the JSON formatter to sort keys first — paste into JSON Formatter, sort alphabetically, copy, and then diff.
- What's the maximum file size supported?
- There's no hard limit, but very large files (100KB+) may cause the browser to slow down as the entire diff is rendered in the DOM. For very large files, it's better to use desktop tools like diff, meld, or VS Code's built-in diff editor which handle larger files more efficiently.
- Can I diff binary files or images?
- No — this tool works with text-based content only. Binary files, images, PDFs, and Office documents need binary-aware diff tools. For PDF comparison, try our Compare PDF tool which renders both PDFs and highlights visual differences page by page.
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