JSONLint Pro

Professional JSON toolkit for macOS

Native performance. Works offline. Handles large files without breaking a sweat.

Download on the

Mac App Store

macOS 12.0+•Apple Silicon & Intel•$6.99

JSONLint Pro - Native JSON Editor for macOS showing diff comparison view

Everything you need for JSON

A complete toolkit for developers who work with JSON daily

Real-time Validation

Instant validation as you type with clear error messages and line numbers. Validates against RFC 8259.

Smart Repair

Auto-fix trailing commas, single quotes, unquoted keys, comments, and more. One click to fix common issues.

Format & Minify

Pretty-print with customizable indentation or minify for production. Sort keys alphabetically.

Format Conversions

Convert JSON to YAML, CSV, TypeScript interfaces, or Swift Codable structs instantly.

Tree View

Visual tree structure with collapsible nodes. Click to copy JSONPath for any value.

Dark Mode

Beautiful syntax highlighting in both light and dark modes. VS Code-inspired color scheme.

Native Performance

Built with SwiftUI for native macOS performance. Handle multi-MB files without lag.

Works Offline

No internet required. Your data never leaves your machine. Complete privacy.

Sample Datasets

14 built-in sample datasets for testing: users, products, GeoJSON, GraphQL, and more.

Smart JSON Repair

Paste broken JSON and let JSONLint Pro fix it automatically. No more manual editing for common mistakes.

Trailing commas
Single quotes to double quotes
Unquoted property keys
Smart/curly quotes to straight quotes
JavaScript comments removal
undefined to null conversion
NaN/Infinity to null conversion

Before

{
  name: 'John Doe',  // unquoted key, single quotes
  "age": 30,
  "active": true,    // trailing comma
}

One-click repair

After

{
  "name": "John Doe",
  "age": 30,
  "active": true
}

Blazing Fast Performance

Native Swift code means no JavaScript overhead. Handle large files that would crash a browser.

Validation Speed

1 KB< 1ms

10 KB< 5ms

100 KB< 50ms

1 MB< 500ms

Formatting Speed

1 KB< 2ms

10 KB< 10ms

100 KB< 100ms

1 MB< 1 sec

Conversions

YAML< 50msper 10KB

CSV< 20msper 10KB

TypeScript< 10msper 10KB

Swift< 10msper 10KB

Benchmarked on Apple Silicon (M1). Performance may vary on Intel Macs.

Convert to Any Format

Transform JSON into the format you need with a single click

JSON→TypeScript

{
  "id": 123,
  "name": "John",
  "active": true
}

interface Root {
  id: number;
  name: string;
  active: boolean;
}

JSON→YAML

{
  "database": {
    "host": "localhost",
    "port": 5432
  }
}

database:
  host: localhost
  port: 5432

Ready to get started?

Download JSONLint Pro and experience professional JSON editing on your Mac.

Download on the

Mac App Store

macOS 12.0+Apple Silicon & Intel$6.99 one-time

Why go native?

Feature	JSONLint Pro	Web Tools
Works offline
Large file support (10MB+)
Native keyboard shortcuts
macOS Services integration
Tab-based workflow		Some
Drag & drop files
Format conversions
Ad-free experience

Prefer the web? The JSONLint web validator is always free with 40+ tools for JSON validation, formatting, and conversion.