Contrast by Unifysy
100% Free Runs in Browser No Data Sent

JSON diff checker for API payloads, configs, and exports

Paste two JSON documents, normalize them, and instantly inspect changed keys, values, and structures. Ideal for API debugging, config reviews, and data export checks.

Text, code, JSON, configs — paste it in and see every difference highlighted. Your data never leaves your device.

Original
Empty
Changed
Empty

Paste your text above to get started

Or to see Contrast in action.

A cleaner way to compare JSON

JSON comparisons get messy fast when formatting changes hide the real differences. Contrast includes JSON normalization so you can focus on changed fields, added objects, and removed values instead of whitespace noise.

  • +Compare API request and response payloads during debugging.
  • +Review config changes across environments before deployment.
  • +Check exported employee, claims, or analytics data for missing or changed fields.

Popular comparison pages

Jump to a focused page for the format or workflow you need to review most often.

Text Compare
Compare text, code, JSON, and document drafts online with a free browser-based diff checker. See added, removed, and changed content without uploading your data.
YAML Diff Checker
Compare YAML files online with a free YAML diff checker. Review config changes for CI pipelines, Kubernetes manifests, and environment files in your browser.
SQL Diff Checker
Compare SQL online with a free SQL diff checker. Review query updates, schema snippets, and migration scripts side by side without installing extra tools.
Compare Two Files Online
Compare two files online with a private browser-based diff tool. Upload text-based files, review line changes, and export the result in seconds.

Private by default

The comparison runs in your browser, which keeps drafts, configs, and internal data on your device.

Made for revision-heavy work

Switch between split and unified diff views, hide unchanged lines, and focus on the edits that matter.

Useful for both business and technical teams

Compare text, files, code, exports, and structured data in one place without extra tooling.

How to use this json diff checker

  1. 1Paste the original content or upload the first file.
  2. 2Paste the revised content or upload the updated file.
  3. 3Choose options like JSON normalization, whitespace rules, or character-level diff when needed.
  4. 4Run the comparison and review the highlighted additions, removals, and changed lines.

Formats teams compare with Contrast

Contrast works well for common text-heavy workflows and structured data review. These are the formats most relevant to this page.

JSON payloadsAPI responsesConfigsExportsAudit snapshots

You can also upload text-based files such as TXT, Markdown, JSON, CSV, XML, HTML, CSS, JavaScript, TypeScript, YAML, and SQL.

JSON Diff Checker FAQ

Does Contrast normalize JSON before comparing it?

Yes. You can turn on JSON normalization so formatting differences do not hide actual key and value changes.

Can I compare nested JSON objects?

Yes. Contrast works with nested JSON and highlights line and word-level differences after formatting.

Is this JSON diff checker good for API testing?

Yes. It is useful for comparing request payloads, response bodies, fixtures, and config snapshots during API debugging.

Will my JSON be uploaded?

No. The comparison runs in your browser, so the JSON stays on your device.