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All Developer Tools

Browse all 50 free developer tools. Everything runs in your browser — no signup, no server calls, no data collection.

FreeDevTool is a single-page reference for the small, repetitive tasks that take up too much of a developer's day — formatting a JSON response, decoding a JWT, generating a UUID, calculating a CIDR subnet, escaping a string for HTML. Every tool listed here is 100% client-side: the file you paste, the token you decode, the regex you test never leaves your browser. There's no account to create, no upgrade prompt, and no advertising.

The toolbox is organized into seven categories: Encoding & Conversion for the formats data needs to travel in (Base64, URL, hex, YAML); Generation & Formatting for the things you produce or pretty-print (JSON, UUID, QR, gradients); Security & Hashing for everyday auth debugging (JWT decode, MD5/SHA hashes); Code & Text Tools for the regex/diff/markdown grind; Optimization & DevOps for the build & ops side (minifiers, cron, chmod, cURL); Network & Time for IP/DNS/subnet math; and SEO & Meta Tools for the meta tags, OG previews, and slugs that ship with every page.

Tools below are searchable by name, alias, or task — try "jwt", "slug", or "chmod" in the box. Bookmark this page if you find yourself opening the same set of tools every week.

Encoding & Conversion

Base64 Encoder / Decoder

Encode and decode Base64 strings instantly.

UNIX Timestamp Converter

Convert between UNIX epoch and human-readable dates.

URL Encoder / Decoder

Encode and decode URL percent-encoded strings.

Hex to RGB Converter

Convert hex color codes to RGB, RGBA, and HSL.

HTML Entity Encoder / Decoder

Encode and decode HTML entities and special characters.

Image to Base64 Encoder

Convert images to Base64 data URIs for embedding.

JSON to CSV Converter

Convert JSON arrays to downloadable CSV files.

Number Base Converter

Convert between binary, decimal, hex, and octal.

YAML to JSON Converter

Convert between YAML and JSON formats instantly.

Byte/Data Size Converter

Convert between bytes, KB, MB, GB, TB and more.

Pixel to REM Converter

Bidirectional px ↔ rem ↔ em with adjustable base.

Generation & Formatting

Generate random v4 UUIDs and GUIDs.

JSON Formatter & Validator

Pretty print, validate, and format JSON data.

Lorem Ipsum Generator

Generate placeholder text for mockups and designs.

Password Generator

Create strong, secure random passwords.

QR Code Generator

Generate QR codes for URLs, text, and Wi-Fi.

Color Palette Generator

Generate color palettes with harmony and contrast tools.

URL Slug Generator

Create SEO-friendly URL slugs from any text.

SQL Formatter & Beautifier

Format, beautify and minify SQL queries.

XML Formatter & Validator

Format, validate and beautify XML documents.

CSS Gradient Generator

Create CSS gradients with a visual editor.

Meta Tag Generator

Generate SEO meta tags and Open Graph markup.

OG Preview Tool

Preview how your page looks on social media.

CSS Box Shadow Generator

Build multi-layer box-shadows with visual sliders.

WCAG Contrast Checker

Check AA/AAA contrast ratios with live pass/fail.

Color Name from Hex

Find the nearest CSS named color for any hex value.

Security & Hashing

JWT Decoder & Inspector

Decode and inspect JWT tokens, headers, and claims.

Hash Generator — MD5 / SHA

Generate MD5, SHA-1, SHA-256, and SHA-512 hashes.

Create signed JWT tokens for testing and development.

Code & Text Tools

Regex Tester & Debugger

Test and debug regular expressions with live matching.

Text Diff Checker

Compare two texts side by side and highlight differences.

Markdown Editor & Preview

Write and preview GitHub Flavored Markdown live.

Regex Explainer

Translate regular expressions into plain English.

String Case Converter

Convert between camelCase, snake_case, kebab-case, and more.

String Escape & Unescape

Escape and unescape strings for JSON, HTML, and URLs.

Character / String Length Counter

Live char, word, line, UTF-8 byte + tweet/SMS limits.

Word / Rich Text to Markdown

Convert pasted Word or HTML content to clean Markdown.

AI Token Counter

Estimate GPT / Claude tokens and cost for any prompt.

Optimization & DevOps

CSS Minifier & Beautifier

Minify or beautify CSS code instantly.

JavaScript Minifier & Beautifier

Minify or beautify JavaScript code.

Cron Expression Generator

Build and parse cron expressions with a visual editor.

Chmod Calculator

Calculate Unix file permissions interactively.

HTTP Status Code Reference

Browse all HTTP status codes with descriptions.

HTML Minifier & Beautifier

Minify or pretty-print HTML with live byte savings.

HTTP Request Builder

Build requests and export as cURL, fetch, axios, Python.

Git Commands Cheatsheet

Searchable reference of 60+ git commands with copy.

Network & Time

IP Address Lookup & Analyzer

Look up IP address details, geolocation, and subnet info.

Timestamp Diff Calculator

Calculate the difference between two timestamps.

DNS Lookup Tool

Query A, AAAA, CNAME, MX, TXT, NS records via DoH.

Relative Time Calculator

Convert timestamps to "3 days ago", "in 2 hours".

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