Open source·Works offline·Zero telemetry

DevToolBox

24 beautifully crafted tools for developers and creators.

Fast, private, client-side. No sign-up, no servers, no surveillance. Just tools that work.

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Works offline100% client-sideOpen source

Tools

100%

Free

Servers

Trackers

The Toolbox

Pick a tool. Get to work.

Every tool runs in your browser. Nothing gets uploaded. Nothing gets tracked.

Developer

JSON Explorer

hot

Visualize, search & compare JSON in a tree view.

Diff Checker

Compare text with character-level highlighting.

Regex Playground

Test regex live with groups & explanations.

Cron Visualizer

Build & explain cron schedules in plain English.

JWT Decoder

new

Inspect JWT header, payload & expiration.

Base64 Encoder

new

Encode & decode Base64 — URL-safe mode too.

Markdown Preview

new

Write markdown, preview HTML live.

Hash Generator

new

MD5, SHA-1, SHA-256, SHA-512 instantly.

REST Client

new

Test APIs — GET, POST, PUT, DELETE in-browser.

SQL Formatter

new

Format & minify SQL for Postgres, MySQL & more.

UUID Generator

new

Bulk v1, v4 & v7 UUIDs with format options.

JSON ⇄ CSV

new

Convert JSON and CSV with custom delimiters.

Case Converter

new

camelCase, snake_case, kebab-case & more.

YAML ⇄ JSON

new

Convert YAML and JSON — nested maps & lists.

Design

CSS Generators

Shadows, gradients, flexbox & glassmorphism.

Color Palette

Palettes, format conversion & WCAG contrast.

OG Preview

Preview links on Google, X, Slack & Discord.

Files & PDF

Image Compressor

Compress & resize images — nothing uploaded.

PDF Tools

new

Merge, split, compress & convert PDFs.

Utility

QR Generator

Custom QR codes — download PNG or SVG.

Timestamp

Convert Unix epochs & compare timezones.

URL Encoder

new

Encode, decode & parse URLs and queries.

Lorem Ipsum

new

Placeholder text — paragraphs, words or lists.

Password Generator

new

Strong random passwords with strength meter.

Showing 24 of 24 tools

Why DevToolBox

Built different. On purpose.

Most dev tool sites are slow, ad-cluttered and upload your data. We built ours the opposite way.

Blazing Fast

Everything runs in your browser. No network latency, no cold starts, no loading spinners.

Private by Default

Your data never leaves your machine. No analytics, no cookies, no third-party scripts.

Always Free

No sign-up walls, no premium tiers, no feature gates. Every tool is fully unlocked, forever.

Smart Features

Pattern libraries, live previews, shareable URLs, copy-to-clipboard, and bulk export.

DevToolBox vs. the rest

Why we're different from the alternatives.

	DevToolBox	Others
Sign-up required	Never	Usually yes
Files uploaded to server	Never	Yes, often
Works offline	Yes	No
Ads / popups	Minimal	Everywhere
Free tier limits	None	1-2/day
Tracks you	No	Yes

Ready to build something?

Pick a tool and start building. No account needed, ever.

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