JSON Toolbox ←

What It Does

Convert, validate, format, and transform JSON and related data formats. Everything runs in your browser. Nothing leaves your machine.

Formats: JSON, CSV, XML, YAML, CSS
Operations: Convert, Format, Minify, Validate, Repair, Diff, Query, Transform
Output: JSON, TypeScript interfaces, JSON Schema, Tree view

Capabilities

Examples

CSV to JSON

Input:

name,role,active
Alice,admin,true
Bob,user,false

Output:

[
  {"name": "Alice", "role": "admin", "active": true},
  {"name": "Bob", "role": "user", "active": false}
]

JSON to TypeScript

Input:

{"id": 1, "name": "Product", "price": 29.99, "tags": ["sale"]}

Output:

interface Root {
  id: number;
  name: string;
  price: number;
  tags: string[];
}

Repair Broken JSON

Input:

{name: 'Alice', active: true,}  // single quotes + trailing comma

Output:

{"name": "Alice", "active": true}

Why Local Execution?

When This Matters

• Converting customer data (PII)
• Working with API keys or credentials
• Processing proprietary business data
• Working in air-gapped environments
• Requiring audit-compliant workflows
• Needing reproducible output

Use Cases

Privacy & Security

Suitable for:

• Personally Identifiable Information (PII)
• Financial data
• Healthcare data (PHI)
• Proprietary business data
• API keys and credentials (for testing)

Privacy Manifesto

JSON Toolbox follows a strict privacy-first philosophy:

1. Your data stays on your machine

All processing happens in the browser. Nothing is sent to backend.

2. No identification

No cookies. No fingerprints. No session IDs. No user IDs.

3. Opt-in storage

localStorage is only used to save your preferences. Cleared with one click.

4. Transparent analytics

Aggregate usage statistics only. Self-hosted on same infrastructure.

5. No reconstruction

Impossible to reconstruct individual sessions or user behaviors.

We believe tools should help, not surveil.

Observability & Analytics

JSON Toolbox uses privacy-first analytics to improve the tool:

Disable analytics

Add to your code before page load:

<script>window.ANALYTICS_DISABLED = true;</script>

PII & Enterprise Compatibility

JSON Toolbox is designed for enterprise environments with strict data policies:

GDPR-friendly

No personal data collected. No consent banners needed.

HIPAA-compatible

PHI never leaves the browser. No third-party exposure.

SOX-compliant

Deterministic output. Verifiable local execution.

Audit trail

No server-side logging of user data. Nothing to audit.

Self-hosted

Hosting mackan.eu yourself? Full control over all infrastructure.

Air-gapped & Offline Mode

JSON Toolbox works in completely isolated environments:

Enable offline mode

1. Load the page once with internet
2. All resources are cached locally
3. Disconnect internet - tool still works

For full air-gap

Disable analytics and download for local hosting:

<script>window.ANALYTICS_DISABLED = true;</script>
<!-- Then download /tools/json/ folder for local hosting -->

All features offline

CSV/XML/YAML/CSS conversion | Format/Validate/Repair | Diff/Query/Schema | Transform/Tree/Utilities

Deterministic Developer Utility

JSON Toolbox follows the Deterministic Developer Utility pattern:

1. Local execution

No network calls during operation

2. Deterministic output

Same input always produces same output

3. Zero onboarding

Paste data, click convert

4. No side effects

Nothing installed, nothing persisted without consent

5. Keyboard-first

Full operation via shortcuts (press ?)

This is a tool, not a service.

Keyboard Shortcuts

Policies

Dependency Policy

Allowed: Capability libraries (local-only, deterministic, self-hosted)

Self-hosted in /vendor/:

• papaparse.min.js — CSV parsing (RFC 4180)
• js-yaml.min.js — YAML parsing (YAML 1.2)
• jsonrepair.min.js — Broken JSON repair
• lucide.min.js — Icon library

Disallowed: Frameworks, build systems, CDN dependencies, external services

Local Execution Policy

• No network calls during tool operation
• No backend or cloud processing
• No telemetry (aggregate analytics only, opt-out)
• All processing in browser JavaScript

Accessibility Policy

• WCAG AA contrast compliance (≥4.5:1)
• Keyboard navigation for all functions
• ARIA labels on interactive elements
• Screen reader compatible

Browser Support

Technical Details

Libraries

• PapaParse — CSV parsing
• js-yaml — YAML parsing
• jsonrepair — JSON repair
• Lucide — UI icons

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• Password Generator — Cryptographically secure passwords
• Image Converter — Local image format conversion
• Coordinate Converter — GPS coordinate transformation