JYF

Diff Checker

Original (A)
Modified (B)

The Best Free Online Diff Checker for JSON & YAML

Our free diff checker lets you compare two pieces of text — JSON configurations, YAML manifests, environment files, API payloads, or any plain text — side-by-side with Git-style color-coded highlighting. Additions are highlighted in green, removals in red, so you can spot every change between two versions in seconds. Whether you're reviewing a Kubernetes manifest before a deploy, checking what changed in an API response, or auditing configuration drift between environments, this online diff tool delivers precise results instantly.

Unlike generic text comparison tools, this diff checker is format-aware. When both inputs are valid JSON or YAML, they are parsed and re-serialized into a canonical form before comparison — meaning cosmetic differences like indentation depth, key order of identical data, or quoting style never pollute your diff. You see the differences that actually matter.

Compare JSON with YAML — Cross-Format Diffing

The killer feature of this tool is cross-format comparison. Have a JSON payload and its equivalent YAML manifest? Paste one into each panel and hit Compare. Both sides are normalized through the same data model, so semantically identical documents produce zero noise — even though their raw syntax looks completely different.

This makes it trivial to verify that a translated configuration is faithful to its original: convert a JSON webhook config to YAML, paste both, and confirm the only thing that changed is the format — not the data.

How to Compare Two Files Online

Comparing files takes seconds: paste your original version into the Original (A) panel and the changed version into Modified (B) — or use the Upload button in either panel to load .json, .yaml, .yml, or .txt files directly. Press Compare (or Ctrl+Enter) and the aligned side-by-side view replaces the editors immediately, with line numbers, change blocks, and navigation controls.

Use the ▲ Prev / Next ▼ buttons to jump between change blocks, tick Changes only to hide all identical lines, and hit Edit Inputs any time to go back and refine either version.

Private by Design — Your Data Never Leaves Your Browser

Every comparison runs entirely inside your browser tab using client-side JavaScript. No server uploads, no accounts, no telemetry on your content. This matters when you're diffing production configs containing database hosts, API tokens, or infrastructure definitions that should never be transmitted to a third party. Close the tab and your data is gone — nothing was ever stored anywhere else.

Frequently Asked Questions

Everything you need to know about comparing JSON, YAML, and plain text.

What is a diff checker?

A diff checker is a tool that compares two texts and highlights their differences. Lines present only in the second version are marked as additions (green), lines present only in the first as deletions (red), and unchanged lines provide context. Developers use diff checkers to review config changes, compare API responses, audit infrastructure manifests, and verify that data transformations preserved everything they should have.

How do I compare two JSON files online?

Paste the first JSON file into the Original (A) panel and the second into Modified (B), or load them with the Upload buttons (.json, .yaml, .yml, .txt supported). Click Compare or press Ctrl+Enter.

Both files are normalized before comparison — so indentation and formatting differences never create false positives. Every highlighted line is a real change: an added key, a removed key, or a modified value.

Can I compare YAML files?

Yes. When both inputs parse as valid YAML, they are converted to a canonical representation before comparison. Differences in indentation style, quoting conventions, or anchor usage won't show up as false changes — you only see genuine data differences, which is exactly what you want when reviewing Kubernetes manifests or CI pipeline edits.

Can I compare a JSON file with a YAML file?

Yes — this is our standout feature. When one input is JSON and the other is YAML, both sides are normalized to the same underlying data model before comparison. Semantically identical documents produce an empty diff regardless of format.

This makes it trivial to verify that a format conversion preserved all your data: convert a config from JSON to YAML, paste both versions, and confirm the diff is clean.

Is it safe to compare sensitive configuration files?

Absolutely yes. All parsing, normalization, and comparison happens entirely inside your browser tab using client-side JavaScript. Nothing is uploaded to any server, nothing persists beyond the page session, and no account is required. Production configs with database hosts, credentials, or infrastructure details can be compared with complete privacy.

What do the colors in the diff mean?

Green rows with a left accent bar exist only in the Modified (B) version — they were added. Red rows exist only in the Original (A) version — they were removed. Rows without highlighting are unchanged context lines present in both versions.

Use the Prev/Next buttons to jump between change blocks, or tick Changes only to collapse all context lines and review just the edits.

Why don't formatting differences show up in my diff?

That's intentional. When both inputs parse as structured data (JSON or YAML), the tool compares canonical representations rather than raw text — so re-indentation, quote-style changes, or equivalent reorderings never appear as noise.

If you specifically want a raw character-level comparison, introduce a syntax error on one side; the tool will then fall back to plain-text mode automatically.

Is there a keyboard shortcut to run a comparison?

Yes. Press Ctrl+Enter (or Cmd+Enter on Mac) from anywhere on the page to run the comparison — the same convention used by popular text comparison tools, so muscle memory transfers directly.