json-differ

# json-differ

Browser-based JSON comparison tool. No backend. Instant diff.

## When to use

- Comparing API response before and after a change
- Diffing config files across environments
- Checking what changed between two database record exports
- Auditing changes to JSON-based feature flags or settings

## Quick Start

Open json-differ in browser. Paste JSON into both panels. Diff appears instantly.

## URL Sharing

Any comparison can be shared as a URL. The full state (both JSON blobs, ignore rules, filter) encodes into the URL hash. Share the URL and the recipient sees the same comparison.

## Features

### Diff kinds

| Marker | Kind | Meaning |
|---|---|---|
| + | added | Key exists in right but not left |
| - | removed | Key exists in left but not right |
| ~ | changed | Key exists in both, value differs |
| (space) | unchanged | Same in both |

### Ignore rules

Exclude volatile fields (timestamps, IDs) from the diff:

- `key_name:timestamp` - ignore all keys named "timestamp" anywhere in the tree
- `exact_path:user.id` - ignore the specific path user.id
- `glob_path:**.updatedAt` - ignore any key matching the glob pattern

### Export formats

- JSON Patch (RFC 6902): machine-applicable patch operations
- Markdown report: human-readable diff summary
- Raw diff JSON: internal diff node structure

## Keyboard Shortcuts

| Shortcut | Action |
|---|---|
| Ctrl+Enter | Run comparison |
| Ctrl+S | Open share modal |
| Escape | Close modal |

## Limitations

- Arrays compared by index, not by content (no LCS algorithm)
- URL hash max ~50KB of encoded JSON
- No syntax highlighting in the editor textarea (plain text input)
- No server-side storage: history is browser LocalStorage only