Free Developer Tools Online

Base64 Encoder & Decoder

Encode text to Base64 or decode Base64 to text instantly. Supports UTF-8 encoding and file-to-Base64 conversion.

URL Encoder & Decoder

Encode or decode URLs and query parameters. Convert special characters to percent-encoding for safe URL usage.

JSON Formatter & Validator

Format, beautify, minify, and validate JSON data. Syntax highlighting with error detection and tree view.

HTML Entity Encoder & Decoder

Encode special characters to HTML entities or decode entities back to characters. Supports named and numeric entities.

MD5 Hash Generator

Generate MD5 hash from any text input instantly. Create checksums for data integrity verification.

SHA-256 Hash Generator

Generate SHA-256 cryptographic hash from text input. Secure hashing using the Web Crypto API in your browser.

Regex Tester

Test and debug regular expressions in real-time. See matches highlighted, capture groups, and get explanations for your patterns.

JWT Decoder

Decode and inspect JSON Web Tokens (JWT). View header, payload, and signature. Verify token expiration and claims.

Unix Timestamp Converter — Current Millis & Epoch Tool

Convert milliseconds to human-readable dates, get all common format snapshots, and generate shareable time links. The essential timestamp toolkit for developers.

Color Converter (HEX ↔ RGB ↔ HSL)

Convert colors between HEX, RGB, HSL, and CMYK formats. Live color preview with copy-to-clipboard for each format.

IndieBase — Indie Dev Stack Selector

Choose the perfect tech stack for your indie product. Get opinionated recommendations for Web SaaS, Indie Games, Chrome Extensions, Mobile Apps, and more — with learning paths, MVP checklists, monetization guides, and launch channels.

Claude Prompt Optimizer

Transform raw prompts into structured, Claude-optimized prompts. Supports CLAUDE.md, SKILL.md, System Prompts, Subagent Prompts, and Tool Definitions with XML formatting and quality scoring.

Claude Prompt Debugger

Analyze and fix Claude-specific prompt bugs: XML tag errors, instruction overflow, hallucination risks, subagent context leaks, and model-prompt mismatches.

CSS Gradient Generator

Create beautiful CSS gradients with a live preview. Linear and radial gradients, up to 5 color stops, angle control, and one-click Random. Copy CSS or download PNG.

Glassmorphism Generator

Generate beautiful glassmorphism CSS effects with realtime preview. Adjust blur, opacity, border, and shadow. Copy CSS or download the component. Free online glass UI generator.

Color Palette Generator

Generate harmonious color palettes from any base color. Choose from 5 color theory schemes, export as CSS variables, Tailwind config, or Figma JSON. Free online palette tool.

WCAG Color Contrast Checker

Check color contrast ratios against WCAG 2.1 AA and AAA accessibility standards. Live preview, pass/fail badges, and automatic color fix suggestions. Free accessibility tool.

CSS Box Shadow Generator

Generate CSS box shadows visually with live preview. Multi-layer shadows, presets (Soft, Neon, Neumorphism), inset mode, and one-click copy. Free online box-shadow tool.

CSS Border Radius Generator

Generate CSS border-radius values visually. Simple, advanced (per-corner), and blob modes. 8 organic blob presets. Live preview and one-click copy. Free online tool.

Aspect Ratio Calculator

Calculate missing dimensions from aspect ratio or find the ratio from width and height. Presets for 16:9, 9:16, 1:1, 4:5 and more. Shows common resolutions. Free online tool.

Font Pairing Generator

Find beautiful Google Fonts pairings for your project. Filter by mood and use case. Live preview with real font rendering. Copy @import URL and CSS snippet. Free font pairing tool.

Number Base Converter

Convert numbers between binary, octal, decimal, and hexadecimal. Supports both integer and floating-point conversions with step-by-step explanation.

CSS Unit Converter

Convert between CSS units: px, rem, em, vw, vh, pt, and percentages. Set base font size for accurate rem/em calculations.

Markdown Previewer

Write and preview Markdown in real-time with syntax highlighting. Supports GFM tables, code blocks, task lists, and export to HTML.

Text to Binary Converter

Convert text to binary code and binary to text. Supports ASCII and UTF-8 encoding with space-separated or continuous output.

Chrome Extension Icon Generator

Upload one image and get all 4 required Chrome extension icon sizes (16×16, 32×32, 48×48, 128×128) instantly. Download as individual PNGs, ready for your extension.

Manifest V3 Generator

Generate a valid Chrome Extension manifest.json (Manifest V3) from a form. No need to memorize syntax — fill in the fields and get a ready-to-use JSON file.

Content Security Policy (CSP) Generator

Build a Content Security Policy header string using checkboxes. No need to memorize complex CSP syntax — configure sources for scripts, styles, images, and more.

Chrome Storage Size Calculator

Paste your JSON data and instantly see its byte size compared to Chrome extension storage limits. Supports chrome.storage.sync (100KB) and chrome.storage.local (5MB).

Chrome Extension Boilerplate Generator

Select your options (popup, background SW, content script, TypeScript) and get a complete Chrome Extension boilerplate with all files pre-configured. Ready to load in Chrome Developer Mode.

Chrome Web Store Description Generator

Generate an optimized Chrome Web Store listing — short description (132 chars) and full description with features, how-to, and privacy section. Copy and paste into Chrome Web Store Developer Dashboard.

Chrome Permissions Explainer

Paste your Chrome Extension permissions array and get plain-English explanations with risk levels for each permission. Perfect for writing your privacy policy and store listing.