💻 Best Free Developer Tools — No Signup Required

📋 JSON Formatter & Validator Popular

Format, minify, and validate JSON with syntax highlighting, tree view, JSON path on click, error detection with line/column, stats, and file upload/download.

🔄 Base64 Encode/Decode

Encode and decode Base64 with text mode, file mode, image-to-Base64 data URI, Base64-to-image preview, URL-safe variant toggle, live conversion, character count, and download support.

🧪 Regex Tester

Test regex patterns with real-time match highlighting, capture groups, replace mode, and a built-in cheatsheet.

🆔 UUID Generator

Generate UUID v4 with bulk generation (1-100), format options (standard, uppercase, no dashes, Base64), UUID validator with version detection, click-to-copy, download as TXT, and generation history.

📝 Markdown Editor & Preview

Full-featured split-pane markdown editor with live preview, formatting toolbar, code blocks, tables, and dark/light theme toggle.

⏰ Cron Expression Generator

Build cron expressions with a visual field builder, see human-readable descriptions, preview next 5 execution times, and reverse-parse any cron expression.

🗃️ SQL Formatter & Beautifier

Format, beautify, and minify SQL queries with syntax highlighting, keyword uppercasing, nested query indentation, and common SQL templates.

✏️ HTML to Markdown Converter

Convert HTML to Markdown or Markdown to HTML with live preview. Supports headings, bold, italic, links, images, lists, code blocks, blockquotes, tables, and more. Copy or download output.

🕐 Timestamp Converter

Convert between epoch timestamps and human-readable dates.

⏱️ Unix Time Converter

Convert between Unix timestamps and dates in both directions.

🔗 URL Encode/Decode

Encode and decode URLs with full URL parser showing protocol, host, path, query params, and fragment. Query string builder, bulk mode, encodeURI vs encodeURIComponent toggle, and live conversion.

🏷️ HTML Entity Encoder/Decoder

Convert HTML special characters to entities or decode them back.

✅ JSON Validator

Validate JSON with detailed error messages, line numbers, and fix suggestions.

🖥️ Live HTML Editor

Write HTML, CSS, and JS with real-time preview side by side.

🔲 CSS Flexbox Generator

Visually generate CSS flexbox layouts with live preview. Copy the generated CSS instantly.

🔲 CSS Grid Generator

Build CSS Grid layouts visually — set columns, rows, gap, and column width template, then copy the ready CSS.

🔍 Text Diff / Compare

Side-by-side diff, unified view, and word-level comparison with line numbers and similarity stats.

📋 Diff Checker

Compare two text blocks with enhanced diff highlighting.

🎭 ASCII Art Generator

Convert text to ASCII art with multiple font styles.

📡 Morse Code Translator

Convert text to Morse code or decode Morse code to text.

📐 Pixel to REM Converter

Convert pixels to REM and REM to pixels with custom base font size.

💻 Text to Binary Converter

Convert text to binary code and binary back to text instantly.

🔎 JSONPath Tester

Test JSONPath expressions against JSON data.

📦 YAML to JSON

Convert YAML to JSON and JSON to YAML instantly.

📝 YAML Validator & Formatter New

Validate, format, and convert YAML with bidirectional YAML/JSON conversion, syntax highlighting, line numbers, error detection, indent selector, stats, and file upload/download.

🎀 CSS Minifier & Beautifier

Minify or beautify CSS code with syntax highlighting, line numbers, and size stats — paste, upload, or drop a .css file and get optimized output instantly.

⚡ JavaScript Minifier & Beautifier

Minify or beautify JavaScript code with syntax highlighting, line numbers, and size stats — paste, upload, or drop a .js file and get optimized output instantly.

📰 XML Formatter & Validator

Beautify, minify, and validate XML with syntax highlighting, line numbers, element/attribute stats, error detection with line references, and file upload/download.

👻 Invisible Character Detector

Find and remove zero-width and invisible Unicode characters.

🖼️ Image to Base64

Convert images to Base64 encoded strings.

📧 Email Validator

Validate single or bulk email addresses — check RFC 5322 format, detect common typos (gmial→gmail), flag disposable domains, and export clean results.

🔄 JSON to YAML Converter

Convert JSON to YAML and YAML to JSON instantly.

🔑 JWT Generator

Generate JWT tokens with custom header and payload.

🌐 API Tester

Simple REST API tester supporting GET, POST, PUT, DELETE requests.

🧩 Regex Generator

Generate regex patterns from plain English descriptions.

📡 HTTP Status Codes

Reference guide for HTTP status codes with search and filtering.

📋 HTML Table Generator Upgraded

Visual HTML table editor with click-to-edit cells, add/remove rows and columns, header row toggle, cell alignment, zebra striping, border styles, 5 color themes, and export as HTML, Markdown, CSV, or LaTeX. Paste from spreadsheet supported.

📐 JSON Schema Generator

Generate JSON Schema from sample JSON data.

🔄 XML to JSON

Convert XML to JSON with attribute preservation, namespace handling, CDATA, auto-typing, and format options.

📦 TOML to JSON

Convert TOML configuration files to JSON format.

🕐 Epoch Converter

Convert between epoch timestamps and human-readable dates with millisecond precision.

🔗 URL Parser

Parse URLs into components like protocol, host, path, and query parameters.

🔍 User Agent Parser

Parse user agent strings into browser, OS, and device details.

🔄 cURL to Code Converter

Convert cURL commands to JavaScript fetch, Python requests, PHP cURL, Node.js axios, Go net/http, and Ruby net/http with syntax-highlighted output and one-click copy.

📋 Regex Cheat Sheet

Interactive regex quick-reference with live test area — learn and test common patterns instantly.

📘 JSON to TypeScript

Generate TypeScript interfaces from JSON — paste your JSON and get a clean, typed interface instantly.

🗜️ HTML Minifier & Beautifier

Minify or beautify HTML code with syntax highlighting, line numbers, size stats, and live preview — paste, upload, or drop an .html file.

💾 Git Commit Message Generator

Generate clean, conventional Git commit messages — pick a type, scope, and description to get a ready-to-use commit message.

⚛️ HTML to JSX Converter

Convert HTML code to JSX/React syntax — transforms class to className, style strings to objects, and self-closes tags.

🔑 JWT Debugger

Decode and inspect JWT tokens — view header, payload, expiration status, and claims without a secret key.

🕐 Unix Timestamp Converter

Convert Unix timestamps to human-readable dates and dates back to Unix timestamps with timezone support.

✂️ CSS Clip-Path Generator

Generate CSS clip-path shapes — choose polygon, circle, ellipse, or inset presets and copy the CSS code instantly.

🎯 CSS Specificity Calculator

Calculate the specificity of any CSS selector — understand which rules win and why, with a clear a-b-c breakdown.

🚫 .gitignore Generator

Generate a ready-to-use .gitignore file for any language or framework — Node.js, Python, Java, Go, Rust, Swift, and more.

🗄️ JSON to SQL

Convert JSON objects or arrays into SQL INSERT statements — supports MySQL, PostgreSQL, SQLite, and generic SQL dialects.

📐 CSS Unit Converter

Convert CSS units instantly — px, em, rem, vw, vh, pt, pc, cm, mm, and inches with custom base font size and viewport dimensions.

💾 Binary to Text Converter

12 conversion modes: binary, hex, decimal, octal, Base64 with hex dump view, encoding selection, and separator options.

▲ CSS Triangle Generator

Generate CSS-only triangles using border tricks — choose from 8 directions, pick color and size, then copy the ready-to-use CSS snippet with live preview.

📝 HTML to Plain Text

Strip HTML tags from any code and extract clean plain text — removes all markup, decodes HTML entities, and preserves or collapses whitespace for readable output.

📁 File Size Converter

Convert file sizes between bytes, kilobytes, megabytes, gigabytes, terabytes, and petabytes using either binary (1024) or decimal (1000) base — see all units at once.

📶 Bandwidth Calculator New

Calculate file transfer times, find required bandwidth for a deadline, and convert between all bandwidth units. Includes common bandwidth reference for 4G, 5G, WiFi 6, and Ethernet standards. Monthly data usage calculator for streaming hours and a streaming quality table showing Netflix and YouTube bandwidth requirements. Copy all results.

✨ HTML Beautifier & Formatter

Beautify and format messy or minified HTML with syntax highlighting, line numbers, and size stats — paste, upload, or drop an .html file and get properly indented, readable code.

📋 ASCII Table Generator

Convert CSV or tab-separated data into beautifully formatted ASCII text tables — paste your data, choose a border style, and copy the plain-text table for documentation or terminal output.

🗜️ JSON Minifier

Minify JSON by removing all whitespace, line breaks, and comments — paste any formatted or pretty-printed JSON and get the smallest possible valid JSON string in one click.

📞 Phone Number Validator

Validate and format phone numbers — check if a phone number is valid, detect country code, format to E.164 and international notation, and see the number type.

🔄 CSS Reset Generator

Generate a customized CSS reset or normalize stylesheet — choose from popular presets (Eric Meyer, Normalize.css, Modern CSS Reset, Tailwind Preflight) or build your own.

🏷️ Variable Name Generator

Convert any phrase into all standard variable naming conventions — camelCase, PascalCase, snake_case, SCREAMING_SNAKE, kebab-case, and more — in one click.

🌈 Color to Tailwind CSS

Find the nearest Tailwind CSS color class for any hex, RGB, or HSL color — paste your color and instantly get the closest Tailwind palette match with the class name to use.

🔄 JSON to XML Converter

Convert JSON to XML with CDATA, @attribute mapping, array wrapping options, indentation, and format/minify JSON.

📷 QR Code Scanner

Scan and decode QR codes directly in your browser — upload an image containing a QR code and instantly extract the encoded text, URL, or data without any app needed.

🔢 ASCII to Hex Converter

Convert ASCII text to hexadecimal and back. Supports spaces, punctuation, and special characters. See decimal, octal, and binary representations alongside hex. Perfect for developers and encoding tasks.

🔍 Regex to English Translator New

Paste any regular expression and get a plain English explanation of every part. Color-coded breakdown of anchors, quantifiers, character classes, groups, and alternations. Reverse mode: describe what you want and get a regex suggestion. Includes 20 common regex patterns and a live test area.

🧮 ChatGPT Token Counter

Count tokens for ChatGPT, GPT-4, GPT-3.5 prompts and estimate API cost instantly in your browser.

💰 LLM API Price Calculator

Compare API prices across OpenAI, Anthropic Claude, Google Gemini, Mistral and more — calculate monthly LLM cost.

🧮 Claude Tokenizer

Count tokens and estimate input cost for Anthropic Claude Opus, Sonnet and Haiku models.

💠 Gemini Token Counter

Count tokens for Google Gemini 2.5 Pro, Flash and Nano models with cost estimation.

📊 LLM Context Window Visualizer

Visualize how much of an LLM context window your prompt uses across 20+ popular models.

🔡 LLM Embedding Cost Calculator

Compare embedding costs across OpenAI, Cohere, Voyage AI and open-source models for millions of docs.

🎯 LLM Fine-Tuning Cost Estimator

Estimate training and inference costs for fine-tuning GPT-4o, Claude Haiku, Gemini Flash and Llama LoRA.

💰 Prompt Token Budget Calculator

Budget tokens across system prompt, few-shot examples, user query and expected output for any LLM.

📦 Batch API Cost Calculator New

Compare real-time vs batch API processing cost across LLM workloads with pricing presets, retry modeling, and monthly savings estimates.

DEVELOPER WORKFLOW

Free Developer Tools Workflow

Handle everyday debugging and data-prep tasks without opening a heavy IDE extension.

DATA WORKFLOW

Free JSON and Data Tools Online

Move structured data from broken paste to clean, validated, copy-ready output.