Free Online Tools
A growing collection of 132 fast, privacy-first tools for developers, designers, and marketers. No sign-up. No tracking. Works offline.
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Featured
8Developer
JSON, encoders, hashes, regex, and code utilities.
JSON Formatter
Format, validate, and minify JSON with inline error reporting.
JSON ↔ YAML Converter
Convert between JSON and YAML formats bidirectionally.
XML Formatter
Pretty-print and minify XML with validation.
Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 to text with UTF-8 support.
UUID Generator
Generate RFC 4122 v4 UUIDs in bulk using the Web Crypto API.
Hash Generator
Generate SHA-1, SHA-256, SHA-384, SHA-512 hashes via Web Crypto.
HMAC Generator
Generate HMAC signatures (SHA-256/384/512) for a message and secret.
JWT Decoder
Decode and inspect JSON Web Token header and payload.
JWT Generator
Generate signed JSON Web Tokens (HS256) with custom claims.
Regex Tester
Test regular expressions with live match highlighting and flags.
URL Encoder / Decoder
Encode or decode URL components and full URLs.
Unix Timestamp Converter
Convert between Unix timestamps and human-readable dates.
Color Converter
Convert colors between HEX, RGB, HSL with a live preview.
HTML Entity Encoder
Encode or decode HTML entities in text.
SQL Formatter
Pretty-print and format SQL queries with keyword casing.
Markdown to HTML
Convert markdown to raw HTML source for emails and static sites.
Text Diff
Compare text at line, word, or character level with unified diff output.
Cron Expression Generator
Build cron schedules visually and preview next run times.
Diff Checker
Compare two texts line-by-line with a color-coded LCS diff.
Markdown Preview
Write Markdown and see a live rendered HTML preview.
CSS Minifier
Minify CSS by removing comments, whitespace, and empty rules.
JS Minifier
Minify JavaScript by removing comments and unnecessary whitespace.
HTML Minifier
Minify HTML by removing comments, whitespace, and empty attributes.
Text
Count, convert, clean, and transform text.
Word Counter
Count words, characters, sentences, and reading time.
Character Counter
Count characters with and without spaces, lines, and bytes.
Case Converter
Convert text to UPPER, lower, Title, camelCase, snake_case, kebab-case.
Slug Generator
Generate URL-safe slugs from any text.
Lorem Ipsum Generator
Generate placeholder Lorem Ipsum paragraphs, sentences, or words.
Text Sorter
Sort lines alphabetically, numerically, or by length.
Remove Blank Lines
Strip empty lines and optionally trim whitespace from text.
Duplicate Line Remover
Remove duplicate lines, optionally case-insensitive.
Reading Time Calculator
Estimate reading and speaking time at multiple speeds.
Unicode Inspector
Inspect every character: code point, name, UTF-8 bytes, category.
Capitalization Tool
Capitalize words, sentences, and titles with AP-style rules.
Text Compare
Compare two texts word-by-word with a color-coded inline diff.
Remove Duplicate Words
Remove duplicate words from text while preserving order.
Finance
Calculators for money, health, and school.
Percentage Calculator
Calculate percentages, increases, decreases, and ratios.
BMI Calculator
Calculate Body Mass Index with metric and imperial units.
VAT Calculator
Add or remove VAT from a price at any rate, with live results.
Loan Calculator
Calculate monthly payments, total interest, and amortization.
Mortgage Calculator
Estimate monthly mortgage payments with taxes and insurance.
Compound Interest Calculator
Project compound interest growth over time.
GPA Calculator
Calculate grade point average across courses with weight.
Currency Converter
Convert between currencies using bundled static reference rates.
Body Fat Calculator
Estimate body fat percentage via the U.S. Navy method.
Unit Converter
Convert length, weight, temperature, and data units.
Invoice Generator
Build a printable invoice with line items, tax, and totals.
BMR Calculator
Calculate Basal Metabolic Rate with the Mifflin-St Jeor formula.
TDEE Calculator
Estimate Total Daily Energy Expenditure from BMR and activity.
Calorie Calculator
Compute daily calorie needs and macro targets for any goal.
Macro Calculator
Split daily calories into protein, carbs, and fat by diet type.
Water Intake Calculator
Estimate daily water needs based on weight, activity, and climate.
Retirement Calculator
Project retirement savings growth with contributions and inflation.
ROI Calculator
Calculate return on investment, annualized ROI, and CAGR.
Savings Calculator
Project savings growth with regular contributions and compounding.
Break-Even Calculator
Find the break-even point in units and revenue for a product.
Profit Margin Calculator
Calculate profit margin, markup, and reverse-engineer costs.
Inflation Calculator
See how inflation erodes purchasing power over time.
Grade Calculator
Compute weighted final grades from assignments and weights.
Quote Generator
Generate inspirational quotes and download them as shareable images.
Flashcard Generator
Build, study, and export flashcard decks with a flip mode.
Citation Generator
Generate APA, MLA, and Chicago citations for books and sites.
Invoice Number Generator
Generate sequential, padded invoice numbers with optional date prefix.
Study Planner
Plan a study schedule across subjects before an exam date.
Tip Calculator
Calculate tips and split bills with quick-percentage presets.
SEO
Meta tags, schema, sitemaps, and content QA.
Meta Tag Generator
Generate SEO meta tags, Open Graph, and Twitter cards.
Title Generator
Generate SEO-optimized page titles from keywords.
CTA Generator
Generate call-to-action button copy and variations.
Robots.txt Generator
Build a robots.txt with rules for bots and sitemaps.
Sitemap Generator
Generate an XML sitemap from a list of URLs.
JSON-LD Generator
Generate JSON-LD structured data (Article, Product, FAQ, etc.).
Open Graph Preview
Preview how a page renders as an Open Graph social card.
Headline Analyzer
Score a headline for length, power words, and sentiment.
Keyword Density Checker
Analyze keyword frequency and density in body text.
Email Signature Generator
Design professional HTML email signatures with live preview.
Campaign URL Builder
Build tagged campaign URLs with custom parameters and presets.
QR Campaign Generator
Generate QR codes with UTM tracking for offline campaigns.
UTM Builder
Build UTM-tagged campaign URLs with live preview and presets.
FAQ Generator
Build FAQ sections with HTML markup and FAQPage JSON-LD schema.
Twitter Card Preview
Preview how a page renders as a Twitter/X card with meta tags.
Breadcrumb Schema Generator
Generate BreadcrumbList JSON-LD for navigation trails.
Organization Schema Generator
Generate Organization JSON-LD with address and social profiles.
Canonical URL Checker
Normalize URLs and generate the canonical link tag.
Blog Outline Generator
Generate structured blog outlines with sections and word budgets.
Security
Passwords, passphrases, and headers.
Password Generator
Generate strong passwords with Web Crypto and a strength meter.
Secure Passphrase Generator
Generate cryptographically secure passphrases from a word list.
Password Strength Checker
Estimate password entropy and crack time honestly.
CSP Generator
Build a Content-Security-Policy header with toggles per directive.
Network
DNS, IP, SSL, headers, and connectivity checks.
DNS Lookup
Query DNS records (A, AAAA, MX, TXT, NS, and more) for any domain.
IP Lookup
Geolocate an IP address with city, region, country, and ISP.
HTTP Header Checker
Inspect HTTP response headers and spot security headers.
SSL Checker
Inspect a site’s TLS certificate: issuer, validity, expiry days.
Ping Tool
Measure HTTP latency (TTFB) to any URL with 1 or 3 pings.
Redirect Checker
Trace the full HTTP redirect chain for any URL.
User-Agent Parser
Parse a user-agent string into browser, OS, and device.
Media
Images, colors, SVG, and file utilities.
QR Generator
Generate downloadable QR codes for any text or URL.
Color Palette Extractor
Extract a dominant color palette from an uploaded image.
Color Contrast Checker
Check WCAG color contrast ratios between two colors.
Image Compressor
Compress images client-side with an adjustable quality slider.
Image Resizer
Resize images to custom dimensions and download.
Favicon Generator
Generate favicon PNGs in multiple sizes from an image or text.
Social Image Generator
Design and export social share images on a canvas.
CSS Gradient Generator
Design multi-stop CSS gradients with live preview and copy CSS.
SVG Viewer
Preview SVG markup with stats, zoom, and background options.
File Size Converter
Convert between bytes, KB, MB, GB, TB, and PB (1024-base).
Alt Text Generator
Generate accessible alt text suggestions with WCAG guidance.
SVG Optimizer
Optimize SVG markup by removing comments, metadata, and whitespace.
MIME Type Detector
Detect MIME types from file extensions or uploaded files.
File Hash Calculator
Compute SHA-1, SHA-256, SHA-384, SHA-512 hashes of any file.
ARIA Validator
Check HTML for accessibility and ARIA issues with fix suggestions.
Merge PDFs
Combine multiple PDF files into one with reordering.
Split PDF
Split a PDF into individual pages, ranges, or fixed-size chunks.
Rotate PDF
Rotate all or specific pages of a PDF by 90, 180, or 270 degrees.
Extract PDF Pages
Extract specific pages from a PDF into a new document.
Compress PDF
Reduce PDF size by stripping metadata and optimizing object streams.
PDF to Images
Render PDF pages to PNG images and inspect PDF structure.
Images to PDF
Convert PNG and JPEG images into a single PDF document.
PDF Metadata Viewer
View PDF metadata, page sizes, and document properties.
File Checksum
Compute CRC32, MD5, SHA-1, SHA-256, SHA-512 checksums of any file.
File Signature Inspector
Identify file types by their magic bytes (hex signatures).
Image Metadata Viewer
Extract and view EXIF metadata from JPEG and TIFF images.
Font Accessibility Checker
Check font sizes, line height, and spacing against WCAG guidelines.
PNG to WebP
Convert PNG images to WebP with adjustable quality and savings.
Misc
AI helpers, tokens, and other utilities.
Token Counter
Estimate token counts for text (rough LLM tokenizer heuristic).
AI Cost Calculator
Estimate LLM API costs across models for any usage volume.
Prompt Optimizer
Score and improve LLM prompts with actionable suggestions.
Prompt Variable Replacer
Fill {{variables}} in prompt templates with live preview.
System Prompt Generator
Build structured system prompts for LLMs with presets.
AI Persona Generator
Design detailed AI personas with traits and system prompts.
Prompt Library
Browse, save, and manage curated LLM prompts with import/export.
Prompt Version Manager
Track prompt versions with diff, restore, and export.
AI Workflow Builder
Design multi-step AI workflows with a visual flow diagram.