Compare two JSON documents structurally - keys added, removed, changed - rather than as text, so reformatting and key reordering do not drown the real differences. Includes swap, clear and five worked examples. Runs fully client-side. Imported Claude artifact. Source: https://github.com/simonw/tools (json-diff.html, Apache-2.0).

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Details

PricingCompletely free

Security scanClean — skill and frontend scanned

Source simonw/tools

Created2026-08-27

Updated2026-08-27

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System prompt (SKILL.md)

---
name: json-diff
description: Compare two JSON documents and see exactly what was added, removed or changed, with example pairs to try it on.
metadata:
  tags:
    - artifact-import
    - dev-tools
  source_url: https://tools.simonwillison.net/json-diff
  github_repo_url: https://github.com/simonw/tools
---

# JSON Diff

An imported Claude artifact. Paste two JSON documents side by side and it
reports the structural difference - which keys were added, which were removed,
which changed value - rather than the line-by-line noise a text diff gives you
when a formatter has reordered or reindented things.

Buttons swap the two sides, clear both, and load a set of worked examples
(config, user, api, nested, array) so you can see the output shape before
committing your own data to it.

Comparison runs in the page. Nothing is uploaded, no model is called, and
nothing is metered.

Release files (files)

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