33 free utilities

Developer Tools

Fast utilities for everyday engineering work.

Generators

QR Code Generator

Generate QR codes from text, URLs, VietQR, Wi-Fi, or contact details.

UUID Generator

Create UUID v4 values and copy them to your clipboard.

Password Generator

Secure passwords with customizable character sets.

Lorem Ipsum

Placeholder text with adjustable paragraph counts.

Slug Generator

Turn titles into URL-friendly slugs — Vietnamese diacritics transliterated.

Random Picker

Draw one random entry from a list you provide.

Fortune Wheel

Spin a wheel to randomly pick from your list.

Encode & decode

Base64 Encode/Decode

Encode binary-safe text for APIs and data URLs, or decode Base64 payloads.

URL Encode/Decode

Percent-encode query values and paths, or decode encoded URLs.

HTML Entities

Escape characters for HTML markup or decode entity references like &.

Escape & Unescape

Make plain text JSON-safe with \\n and \\" escapes, or reverse them.

Case Converter

Switch between camelCase, snake_case, kebab-case, and other naming styles.

Vietnamese Typing

Type Vietnamese with Telex, VNI, or VIQR — no Unikey or EV Key needed.

Parsers & converters

JWT Parser

Decode JWTs to inspect header and payload claims.

Cron Parser

Parse cron expressions and read their schedules.

Cron Builder

Build cron expressions with presets and preview next run times.

Hash Utilities

MD5, SHA-256, SHA-512, and bcrypt — client-side only.

Date & Time

Unix timestamps, ISO dates, JSON /Date()/ strings, and a live clock.

JSON Formatter

Pretty-print, minify, or validate JSON with clear parse errors.

YAML ↔ JSON

Convert YAML configs to JSON and back for CI or API work.

CSV ↔ JSON

Convert CSV with headers to JSON arrays, or export JSON back to CSV.

Color Converter

Convert between HEX, RGB, and HSL color formats.

Markdown Preview

Live markdown preview with word count — HTML sanitized client-side.

Number & Byte Formatter

Format large numbers and convert bytes between SI and IEC units.

IPv4 Subnet Calculator

Network, broadcast, host range, and masks from IPv4 CIDR notation.

PEM / Certificate Viewer

Inspect X.509 certificate fields from PEM text — parsed locally.

ASCII Table

Reference for ASCII codes 0–127 with decimal, hex, and control names.

Countdown Timer

Large countdown clock with sound and optional alerts when time runs out.

Text Counter

Count characters, words, and paragraphs in any text.

Text Diff

Compare two texts line by line with clear additions and removals.

JSON Diff

Deep-compare JSON documents and list changed paths.

Base Converter

Convert integers between binary, octal, decimal, and hex.

Regex Tester

Test JavaScript regular expressions against sample text.

33 of 33 tools

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