Dev Utilities

Free online color blind simulator. Preview how colors and images appear under color blindness, color weakness, and red-green color blindness perspectives. Perfect for accessible design, UI color checking, and visual accessibility optimization.

Online color converter supporting 14 color formats including HEX, RGB, RGBA, HSL, HSV, CMYK, OKLCH, LAB, LCH with instant conversion. Features WCAG contrast checking, color harmony schemes, shade generation, image color picker, and batch processing. All processing happens locally in your browser with no upload required, ready to use instantly on desktop and mobile. Professional tool for designers and frontend developers.

Free online .htaccess to Nginx converter. Convert Apache RewriteRule, redirects, and URL rewriting rules to Nginx Rewrite configuration. Perfect for website migration, server switching, and operations troubleshooting.

GeekFormat online SQL Converter instantly converts SQL INSERT statements and CREATE TABLE scripts into JSON, CSV, TSV, XML, YAML, HTML tables, Markdown tables, JSON Lines and other formats. It supports multiple INSERT statements, multi-value tuples and multiple tables, and automatically recognizes numbers, strings, NULL, booleans and hexadecimal literals, compatible with the quoting styles of MySQL, PostgreSQL, SQLite, SQL Server and more. All processing happens locally in your browser—no data is uploaded.

Free online cookie parser with dual modes for Cookie request headers / document.cookie and Set-Cookie response headers. It automatically splits names and values, shows URL-decoded results, recognizes SameSite / Secure / HttpOnly / Path / Domain / Expires / Max-Age attributes, and supports JSON plus Netscape Cookie File export. Ideal for frontend debugging, login-state troubleshooting, crawler cookie reuse, and browser network debugging. Everything runs locally in your browser.

Free online Cron expression generator. Visually generate Cron, crontab, and scheduled task expressions with execution time preview. Perfect for Linux operations, backend development, and automation scheduling configuration.

Free online Cron expression validator. Check Cron and crontab syntax correctness and preview future execution times. Perfect for scheduled task debugging, rule verification, and pre-launch checks.

Free online CSS formatter. Support CSS code beautification, indentation organization, code layout, and CSS Formatter scenarios. Perfect for development debugging, code review, and collaborative organization.

Free online CSS minifier. Support CSS code compression, removing extra spaces and line breaks. Perfect for page publishing, static resource optimization, and production environment size control.

CSV to Excel tool page is reserved. Will later support converting CSV files to Excel or XLSX spreadsheets with export download. Current features are under development. You can bookmark this page and wait for the feature launch.

Free online CSV Viewer. Quickly view CSV data in table format, support column sorting and data filtering. Perfect for data preview and data analysis.

Free online CSV editor. Support CSV data viewing, editing, filtering and sorting. Perfect for data processing, data analysis and data conversion preparation.

Free online currency converter with real-time exchange rates. Convert USD, EUR, GBP, and more instantly. Perfect for travel, cross-border shopping, and international payments.

Free online text comparison tool. Support comparing differences between two texts, code, and configuration content. Perfect for copy proofreading, code review, version comparison, and configuration troubleshooting.

Free online Excel to CSV converter. Quickly convert Excel files (XLSX, XLS) to CSV format. Perfect for data migration, data import and data processing.

Online Favicon Generator supporting text, image, and Emoji modes to create website icons. One-click export of complete ZIP package including favicon.ico, 16/32/180/192/512 multi-size PNGs, and site.webmanifest. Auto-generates HTML head link code, with square/rounded/circle shape options and transparent background support. Pure Canvas local generation.

Free online CSS formatter. Beautify CSS code, organize indentation and structure. Perfect for development debugging, code review and team collaboration.

Free online HTML formatter. Beautify HTML code, organize tag indentation and structure. Perfect for development debugging, code review and template editing.

Free online Markdown formatter. Beautify Markdown document format, organize headings, lists and code blocks. Perfect for document writing, README editing and note organization.

Free online XML formatter. Support XML beautification, compression, indentation organization, and syntax validation. Perfect for interface message viewing, configuration file organization, and development debugging.

Free online Hexadecimal Converter. Instantly convert between Hex, Decimal, Binary, Octal and 2–36 base number systems. Supports fractional numbers, high-precision calculation, no registration required.

Free online HTML formatter. Support HTML code beautification, indentation organization, code layout, and HTML Formatter scenarios. Perfect for development debugging, code review, and collaborative organization.

Free online HTML minifier. Support HTML code compression, removing extra spaces and line breaks. Perfect for page publishing, static resource optimization, and production environment size control.

Free online HTML to Markdown converter. Convert webpage source code, rich text, and article snippets to Markdown syntax. Perfect for blog migration, document organization, and knowledge base editing.

Free online Markdown to HTML converter. Convert Markdown text to HTML webpage code with real-time preview. Perfect for blog publishing, documentation launch, email templates, and content migration.

Online JavaScript/JS code beautifier tool with Prettier-style formatting options (indent width, semicolons, quote type, trailing commas, arrow function parentheses), supports code minification and obfuscation, compatible with TypeScript/JSX/TSX/JSON/CSS/HTML for 7 languages total, built-in CodeMirror editor with syntax highlighting, real-time preview, keyboard shortcuts, file upload/download, ideal for frontend development, code review, pre-production deployment processing.

Free online JS minifier. Support JavaScript code compression, removing extra spaces and line breaks. Perfect for page publishing, static resource optimization, and production environment size control.

Online JSX formatter tool that beautifies React JSX/TSX code based on Prettier v3. Supports 12 formatting configurations (indentation, semicolons, quotes, trailing commas, bracket spacing, arrow function parentheses, print width, JSX single quotes, JSX bracket same line, property quotes, etc.), one-click minification, file upload/download, history records, browser-local processing with no code upload.

Free online JSX minifier. Support React JSX code compression, removing extra spaces and line breaks. Perfect for page publishing, static resource optimization, and production environment size control.

A free online keyword clustering tool that supports quickly grouping Chinese and English keyword lists by subject words and shared word fragments. It is suitable for SEO vocabulary organization, long-tail keyword classification, content planning, topic page layout and column construction. After clustering is completed, you can continue to review the grouping and plan the page structure.

Generate Lorem Ipsum placeholder text (dummy text/filler text) online, supports custom paragraph count (1-20 paragraphs) and words per paragraph (10-200 words), generates Latin vocabulary text based on seeded random algorithm, click regenerate to get new content, suitable for web design typography demos, prototype placeholders, frontend template development, PPT poster typography testing. Generated locally in browser, no internet required.

Free online Markdown table generator. Support quick conversion of CSV or text to Markdown Table. Perfect for GitHub README, technical documentation, tutorial articles, and knowledge base formatting.

Browser-based Meta Tag Generator supporting title, meta description, keywords, canonical, Open Graph, Twitter Card, robots, author, theme-color and other meta tags. Automatically handles HTML entity escaping (&<>"'), provides SEO character length guidance (title 50-60 characters, description 120-160 characters) with color status indicators, supports one-click copy, download as meta-tags.html file, real-time preview, and structured output across three sections (Basic SEO / Open Graph / Twitter Card).

Free secure password generator using browser Web Crypto CSPRNG. Generate strong random passwords, memorable passphrases, and numeric PINs. Strength meter, batch export, local-only generation.

Online password strength checker that evaluates password security based on Shannon Entropy algorithm, featuring 5-star rating, estimated cracking time across three scenarios (PC/supercomputer/rate-limited online attack), 7 security indicators (length, case, digits, special characters, repetition patterns, common passwords), built-in cryptographically secure random password generator, and browser-local processing with no password upload.

Free online 2-in-1 QR Code generator and Barcode generator, supporting 9 QR Code types (URL/WiFi/vCard/SMS/Phone/Email/Geolocation/Calendar Event/Text) and 6 barcode formats (CODE128/EAN-13/UPC etc.), customizable colors, styles and Logo, batch generation with ZIP download, pure frontend generation with no data upload.

Free online Regex Tester with JavaScript real-time matching, Capture Group/Named Group inspection, replace preview, built-in regex syntax explanation. Web Worker sandbox execution prevents ReDoS. Includes common regex template library (email/phone/URL/IP/UUID etc.), ready to use without registration.

Free online Slugify tool. Support quick conversion of English titles, article titles, and word phrases to URL Slugs, permalinks, and SEO-friendly aliases. Perfect for blog publishing, independent site building, and route naming.

Free online SQL builder. Visually generate CREATE TABLE, SELECT, INSERT, UPDATE, DELETE, and other common SQL statements. Perfect for database learning, backend development, table structure design, and query statement assembly.

Online SQL formatter tool supporting SQL beautification, minification, and syntax validation. Compatible with 20 database dialects including MySQL, PostgreSQL, SQLite, SQL Server, Oracle, and more. Customize formatting options such as keyword case, indent style, logical operator newline placement, and expression width. Offers 4 preset styles with built-in sample SQL, file upload/download, URL sharing, and keyboard shortcuts. All processing happens locally in your browser—SQL statements are never uploaded to any server.

Free online word counter tool that counts words, characters (with/without spaces), sentences, lines, and estimates reading time in real-time. All processing happens locally in your browser - no text uploaded to servers. Perfect for writing, essays, WeChat articles, SEO content, and more.

Free online Text Translator. Support multi-language text translation, suitable for document translation, website localization and cross-language communication.

All-in-one online time tool: global world clock with flags + SVG analog clocks + day/night indicators, bidirectional Unix timestamp conversion (seconds/milliseconds), countdown timer with quick presets. Shows your local current time and timestamp on load, runs entirely in-browser with no internet required.

Free online TS formatter. Support TypeScript code beautification, indentation organization, code layout, and TS Formatter scenarios. Perfect for development debugging, code review, and collaborative organization.

Free online TS minifier. Support TypeScript code compression, removing extra spaces and line breaks. Perfect for page publishing, static resource optimization, and production environment size control.

Free online TSX formatter. Support React TypeScript code beautification, indentation organization, and component layout. Perfect for TSX component development, type debugging, and team collaboration.

Free online TSX minifier. Support React TypeScript code compression, removing extra spaces and line breaks. Perfect for component snippet optimization and pre-publishing preparation.

Free online Unix timestamp converter supporting bidirectional conversion between seconds, milliseconds, and microseconds with automatic unit detection. Switch between UTC and local timezone, view live current timestamp, and get code examples for JavaScript, Python, Go, and Bash. Perfect for development debugging, log analysis, and API integration.

Free online UUID generator supporting UUID v1/v4/v5, ULID, and NanoID in one tool. Bulk generate up to 100 IDs, toggle case/hyphen formatting, validate UUID version recognition. Ideal for database primary keys, distributed IDs, API request identifiers, and test data generation. Copy all or export to TXT/JSON. All generation runs locally in your browser—no data uploaded.

Free online YAML formatter. Support YAML beautification, syntax checking, indentation organization, and configuration layout. Perfect for Kubernetes, Docker Compose, and various YAML configuration file processing.

Convert between camelCase, snake_case, kebab-case and more naming styles