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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JSON Formatter Format, validate, and minify JSON with inline error reporting.
Developer Password Generator Generate strong passwords with Web Crypto and a strength meter.
Security QR Generator Generate downloadable QR codes for any text or URL.
Media UUID Generator Generate RFC 4122 v4 UUIDs in bulk using the Web Crypto API.
Developer Color Converter Convert colors between HEX, RGB, HSL with a live preview.
Developer Markdown Preview Write Markdown and see a live rendered HTML preview.
Developer Hash Generator Generate SHA-1, SHA-256, SHA-384, SHA-512 hashes via Web Crypto.
Developer Invoice Generator Build a printable invoice with line items, tax, and totals.
Finance { }
Developer JSON, encoders, hashes, regex, and code utilities. 23 tools JSON Formatter Format, validate, and minify JSON with inline error reporting.
Developer JSON ↔ YAML Converter Convert between JSON and YAML formats bidirectionally.
Developer XML Formatter Pretty-print and minify XML with validation.
Developer Base64 Encoder / Decoder Encode text to Base64 or decode Base64 to text with UTF-8 support.
Developer UUID Generator Generate RFC 4122 v4 UUIDs in bulk using the Web Crypto API.
Developer Hash Generator Generate SHA-1, SHA-256, SHA-384, SHA-512 hashes via Web Crypto.
Developer HMAC Generator Generate HMAC signatures (SHA-256/384/512) for a message and secret.
Developer JWT Decoder Decode and inspect JSON Web Token header and payload.
Developer JWT Generator Generate signed JSON Web Tokens (HS256) with custom claims.
Developer Regex Tester Test regular expressions with live match highlighting and flags.
Developer URL Encoder / Decoder Encode or decode URL components and full URLs.
Developer Unix Timestamp Converter Convert between Unix timestamps and human-readable dates.
Developer Color Converter Convert colors between HEX, RGB, HSL with a live preview.
Developer HTML Entity Encoder Encode or decode HTML entities in text.
Developer SQL Formatter Pretty-print and format SQL queries with keyword casing.
Developer Markdown to HTML Convert markdown to raw HTML source for emails and static sites.
Developer Text Diff Compare text at line, word, or character level with unified diff output.
Developer Cron Expression Generator Build cron schedules visually and preview next run times.
Developer Diff Checker Compare two texts line-by-line with a color-coded LCS diff.
Developer Markdown Preview Write Markdown and see a live rendered HTML preview.
Developer CSS Minifier Minify CSS by removing comments, whitespace, and empty rules.
Developer JS Minifier Minify JavaScript by removing comments and unnecessary whitespace.
Developer HTML Minifier Minify HTML by removing comments, whitespace, and empty attributes.
Developer Tt
Text Count, convert, clean, and transform text. 13 tools Word Counter Count words, characters, sentences, and reading time.
Text Character Counter Count characters with and without spaces, lines, and bytes.
Text Case Converter Convert text to UPPER, lower, Title, camelCase, snake_case, kebab-case.
Text Slug Generator Generate URL-safe slugs from any text.
Text Lorem Ipsum Generator Generate placeholder Lorem Ipsum paragraphs, sentences, or words.
Text Text Sorter Sort lines alphabetically, numerically, or by length.
Text Remove Blank Lines Strip empty lines and optionally trim whitespace from text.
Text Duplicate Line Remover Remove duplicate lines, optionally case-insensitive.
Text Reading Time Calculator Estimate reading and speaking time at multiple speeds.
Text Unicode Inspector Inspect every character: code point, name, UTF-8 bytes, category.
Text Capitalization Tool Capitalize words, sentences, and titles with AP-style rules.
Text Text Compare Compare two texts word-by-word with a color-coded inline diff.
Text Remove Duplicate Words Remove duplicate words from text while preserving order.
Text %
Finance Calculators for money, health, and school. 29 tools Percentage Calculator Calculate percentages, increases, decreases, and ratios.
Finance BMI Calculator Calculate Body Mass Index with metric and imperial units.
Finance VAT Calculator Add or remove VAT from a price at any rate, with live results.
Finance Loan Calculator Calculate monthly payments, total interest, and amortization.
Finance Mortgage Calculator Estimate monthly mortgage payments with taxes and insurance.
Finance Compound Interest Calculator Project compound interest growth over time.
Finance GPA Calculator Calculate grade point average across courses with weight.
Finance Currency Converter Convert between currencies using bundled static reference rates.
Finance Body Fat Calculator Estimate body fat percentage via the U.S. Navy method.
Finance Unit Converter Convert length, weight, temperature, and data units.
Finance Invoice Generator Build a printable invoice with line items, tax, and totals.
Finance BMR Calculator Calculate Basal Metabolic Rate with the Mifflin-St Jeor formula.
Finance TDEE Calculator Estimate Total Daily Energy Expenditure from BMR and activity.
Finance Calorie Calculator Compute daily calorie needs and macro targets for any goal.
Finance Macro Calculator Split daily calories into protein, carbs, and fat by diet type.
Finance Water Intake Calculator Estimate daily water needs based on weight, activity, and climate.
Finance Retirement Calculator Project retirement savings growth with contributions and inflation.
Finance ROI Calculator Calculate return on investment, annualized ROI, and CAGR.
Finance Savings Calculator Project savings growth with regular contributions and compounding.
Finance Break-Even Calculator Find the break-even point in units and revenue for a product.
Finance Profit Margin Calculator Calculate profit margin, markup, and reverse-engineer costs.
Finance Inflation Calculator See how inflation erodes purchasing power over time.
Finance Grade Calculator Compute weighted final grades from assignments and weights.
Finance Quote Generator Generate inspirational quotes and download them as shareable images.
Finance Flashcard Generator Build, study, and export flashcard decks with a flip mode.
Finance Citation Generator Generate APA, MLA, and Chicago citations for books and sites.
Finance Invoice Number Generator Generate sequential, padded invoice numbers with optional date prefix.
Finance Study Planner Plan a study schedule across subjects before an exam date.
Finance Tip Calculator Calculate tips and split bills with quick-percentage presets.
Finance SEO
SEO Meta tags, schema, sitemaps, and content QA. 19 tools Meta Tag Generator Generate SEO meta tags, Open Graph, and Twitter cards.
SEO Title Generator Generate SEO-optimized page titles from keywords.
SEO CTA Generator Generate call-to-action button copy and variations.
SEO Robots.txt Generator Build a robots.txt with rules for bots and sitemaps.
SEO Sitemap Generator Generate an XML sitemap from a list of URLs.
SEO JSON-LD Generator Generate JSON-LD structured data (Article, Product, FAQ, etc.).
SEO Open Graph Preview Preview how a page renders as an Open Graph social card.
SEO Headline Analyzer Score a headline for length, power words, and sentiment.
SEO Keyword Density Checker Analyze keyword frequency and density in body text.
SEO Email Signature Generator Design professional HTML email signatures with live preview.
SEO Campaign URL Builder Build tagged campaign URLs with custom parameters and presets.
SEO QR Campaign Generator Generate QR codes with UTM tracking for offline campaigns.
SEO UTM Builder Build UTM-tagged campaign URLs with live preview and presets.
SEO FAQ Generator Build FAQ sections with HTML markup and FAQPage JSON-LD schema.
SEO Twitter Card Preview Preview how a page renders as a Twitter/X card with meta tags.
SEO Breadcrumb Schema Generator Generate BreadcrumbList JSON-LD for navigation trails.
SEO Organization Schema Generator Generate Organization JSON-LD with address and social profiles.
SEO Canonical URL Checker Normalize URLs and generate the canonical link tag.
SEO Blog Outline Generator Generate structured blog outlines with sections and word budgets.
SEO 🔒
Security Passwords, passphrases, and headers. 4 tools Password Generator Generate strong passwords with Web Crypto and a strength meter.
Security Secure Passphrase Generator Generate cryptographically secure passphrases from a word list.
Security Password Strength Checker Estimate password entropy and crack time honestly.
Security CSP Generator Build a Content-Security-Policy header with toggles per directive.
Security 🌐
Network DNS, IP, SSL, headers, and connectivity checks. 7 tools DNS Lookup Query DNS records (A, AAAA, MX, TXT, NS, and more) for any domain.
Network IP Lookup Geolocate an IP address with city, region, country, and ISP.
Network HTTP Header Checker Inspect HTTP response headers and spot security headers.
Network SSL Checker Inspect a site’s TLS certificate: issuer, validity, expiry days.
Network Ping Tool Measure HTTP latency (TTFB) to any URL with 1 or 3 pings.
Network Redirect Checker Trace the full HTTP redirect chain for any URL.
Network User-Agent Parser Parse a user-agent string into browser, OS, and device.
Network ◐
Media Images, colors, SVG, and file utilities. 28 tools QR Generator Generate downloadable QR codes for any text or URL.
Media Color Palette Extractor Extract a dominant color palette from an uploaded image.
Media Color Contrast Checker Check WCAG color contrast ratios between two colors.
Media Image Compressor Compress images client-side with an adjustable quality slider.
Media Image Resizer Resize images to custom dimensions and download.
Media Favicon Generator Generate favicon PNGs in multiple sizes from an image or text.
Media Social Image Generator Design and export social share images on a canvas.
Media CSS Gradient Generator Design multi-stop CSS gradients with live preview and copy CSS.
Media SVG Viewer Preview SVG markup with stats, zoom, and background options.
Media File Size Converter Convert between bytes, KB, MB, GB, TB, and PB (1024-base).
Media Alt Text Generator Generate accessible alt text suggestions with WCAG guidance.
Media SVG Optimizer Optimize SVG markup by removing comments, metadata, and whitespace.
Media MIME Type Detector Detect MIME types from file extensions or uploaded files.
Media File Hash Calculator Compute SHA-1, SHA-256, SHA-384, SHA-512 hashes of any file.
Media ARIA Validator Check HTML for accessibility and ARIA issues with fix suggestions.
Media Merge PDFs Combine multiple PDF files into one with reordering.
Media Split PDF Split a PDF into individual pages, ranges, or fixed-size chunks.
Media Rotate PDF Rotate all or specific pages of a PDF by 90, 180, or 270 degrees.
Media Extract PDF Pages Extract specific pages from a PDF into a new document.
Media Compress PDF Reduce PDF size by stripping metadata and optimizing object streams.
Media PDF to Images Render PDF pages to PNG images and inspect PDF structure.
Media Images to PDF Convert PNG and JPEG images into a single PDF document.
Media PDF Metadata Viewer View PDF metadata, page sizes, and document properties.
Media File Checksum Compute CRC32, MD5, SHA-1, SHA-256, SHA-512 checksums of any file.
Media File Signature Inspector Identify file types by their magic bytes (hex signatures).
Media Image Metadata Viewer Extract and view EXIF metadata from JPEG and TIFF images.
Media Font Accessibility Checker Check font sizes, line height, and spacing against WCAG guidelines.
Media PNG to WebP Convert PNG images to WebP with adjustable quality and savings.
Media ✦
Misc AI helpers, tokens, and other utilities. 9 tools Token Counter Estimate token counts for text (rough LLM tokenizer heuristic).
Misc AI Cost Calculator Estimate LLM API costs across models for any usage volume.
Misc Prompt Optimizer Score and improve LLM prompts with actionable suggestions.
Misc Prompt Variable Replacer Fill {{variables}} in prompt templates with live preview.
Misc System Prompt Generator Build structured system prompts for LLMs with presets.
Misc AI Persona Generator Design detailed AI personas with traits and system prompts.
Misc Prompt Library Browse, save, and manage curated LLM prompts with import/export.
Misc Prompt Version Manager Track prompt versions with diff, restore, and export.
Misc AI Workflow Builder Design multi-step AI workflows with a visual flow diagram.
Misc