Web Dev Toolkit ロゴ
Developer's Toolkit Practical browser-only tools for developers.

100% Client-side processing. Your data never leaves your browser.

Developer tools that stay in your browser

Practical browser-only tools for developers.

JSON Formatter & Model Generator

Format JSON and generate Swift Codable structs or Kotlin data classes from the same input.

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URL Encode/Decode & Deep Link Parser

Easily encode, decode, and parse URL parameters for debugging.

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UNIX Timestamp ⇄ Date Converter

Convert between UNIX timestamps and date-time. Features auto-detection of seconds/milliseconds and flexible parsing of loose date formats.

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QR Code Generator

Generate QR codes from text or URLs. Customize sizes, colors, error correction levels, and download as PNG or SVG.

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Favicon Generator

Create favicons from images, emoji, or text. Download favicon.png, apple-touch-icon.png, and favicon.ico as a ZIP bundle.

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JWT Decoder & Inspector

Decode JWT tokens, inspect expiration in real-time, edit claims, and resign using an HS256 secret key entirely in your browser.

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Regex Tester & Visualizer

Test regular expressions with real-time match highlighting, capture group extraction, replace output, and cheatsheet insertions.

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YAML Formatter & YAML ↔ JSON Converter

Bidirectional real-time YAML ↔ JSON conversion with syntax validation, tree view, JSON Schema generation, Git-style diff, key sorting, and template snippets.

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Advanced Text & JSON Diff Checker

Compare text or JSON differences securely in your browser. Features UI freeze protection via Web Workers, semantic JSON Tree Diff, credential masking, and standalone HTML export.

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