Free Online Programming Tools

Free online HTTP status code query tool, provides a complete HTTP status code reference manual. Supports filtering by category, keyword search, and includes detailed explanations, causes, and solutions for all standard status codes including 1xx informational responses, 2xx success responses, 3xx redirections, 4xx client errors, and 5xx server errors.

Free online HTML entity escape tool, supports HTML code escaping and unescaping, provides multiple escape modes such as basic, complete, minimal, numeric, etc., quickly convert HTML special characters, prevent XSS attacks and HTML parsing errors.

Free online URL analysis tool, supports URL parsing, validation, formatting, and comparison. One-click analyze URL structure, validate URL validity, format URL, compare differences between two URLs, suitable for web development, API debugging, and link management.

Free online KeyCode lookup tool, real-time detection of keyboard keys, query keyCode, code, which and other code value information. Supports lookup of common key codes for letter keys, number keys, function keys, control keys, navigation keys, symbol keys, etc. Provides key type classification filtering, an essential development aid for front-end developers and programmers.

Free online Git commands cheat sheet tool, provides quick lookup of commonly used Git commands and one-click copy functionality. Includes complete categories such as basic operations, branch management, remote operations, history viewing, undo operations, supports search and category filtering.

Free online UUID generation tool, supports batch generation of all UUID versions V1/V3/V4/V5, with customizable format (uppercase/lowercase, with or without hyphens), one-click copy or download. Suitable for database primary keys, API keys, distributed IDs, session identifiers and other scenarios, no download or installation required, free and ad-free.

Free online ASCII character table lookup tool, supports decimal, hexadecimal, binary, octal conversion, includes complete character set of basic ASCII (0-127) and extended ASCII (128-255), essential character encoding query tool for programmers.

Free online common port lookup tool, supports searching by port number, service name and description, provides port information queries in categories including Web services, databases, remote access, file transfer, email services and more.

Free online JSON difference comparison tool, supports comparing differences between two JSON objects, highlights added, deleted and modified content. Supports JSON formatting, real-time comparison, one-click copy results, suitable for API interface debugging, data comparison and other scenarios.

Free online subnet calculator, supports IP address subnet division, CIDR calculation, network address, broadcast address, usable IP range, host count and other quick calculations. Suitable for network planning, IP allocation, subnet mask calculation and other scenarios.

Free online Base64 file conversion tool, supports mutual conversion between files and Base64 encoding. Convert images, documents and other files to Base64 strings, or decode Base64 to download files. Supports drag-and-drop upload, batch conversion, no software installation required.

Free online Linux file permission calculation tool, supports mutual conversion between symbolic and numeric permissions, supports special permissions like SetUID, SetGID, Sticky Bit, displays chmod command in real time.

Free online directory tree generation tool, generates beautiful ASCII or Unicode format directory tree structures from local folders, with customizable display options, indentation styles, and connector styles. One-click copy results, suitable for project documentation, README files and other scenarios.

Free online advanced JSON extraction tool, supports using JSONPath expressions to extract, filter and transform fields from complex JSON data. Supports data preview and multi-format export (JSON/CSV/TXT), suitable for API debugging, data processing, data analysis and other scenarios.

Free online JavaScript code obfuscation tool, supports multiple obfuscation techniques including control flow flattening, string obfuscation, dead code injection, variable name obfuscation, to protect your JavaScript code security. Suitable for frontend code protection, commercial application anti-reverse engineering, open source project security hardening and other scenarios.

Free online JavaScript/TypeScript code minification and beautification tool, supports code compression, variable name obfuscation, comment removal, code formatting, syntax highlighting and more. One-click minify JS code to reduce file size, or beautify code to improve readability. Suitable for frontend performance optimization, debugging, project deployment and other scenarios.

Free online Meta tag analysis tool to detect webpage SEO meta tags including Title, Description, Keywords, Open Graph, Twitter Card, and provide optimization suggestions and scores.

Free online XML formatting and compression tool. Supports XML beautification, minification, validation, escaping, tree view, and more. Real-time preview, one-click copy, perfect for development debugging and data viewing.

Free online HTML formatter tool with beautify, minify, and validate functions. Auto-indent, syntax highlighting, error checking for clean HTML code. Supports HTML5 standard.

Free online CSS minifier and formatter tool. Beautify, compress, and optimize CSS code. Remove unnecessary whitespace and comments, reduce file size, and improve webpage loading speed.

Free online code comment removal tool. Supports JavaScript, TypeScript, CSS, HTML, Python, Java, PHP, SQL, C/C++ and more programming languages. Clean up all comments from your code with one click.

Free online IP address lookup tool. Query IP geolocation, ISP, ASN, timezone and more. Supports IPv4 and IPv6 address lookup, local IP detection, and batch query for multiple IPs.

Free online MAC address lookup tool. Query device manufacturer information via the first 24-bit OUI of MAC address. Supports batch query and MAC address format validation.

Free online responsive layout testing tool. Real-time detection of browser viewport size, breakpoint info, device pixel ratio, screen orientation, and more. Helps developers debug responsive web design.

Free online CSS dashed border generator tool. Customize border style, color, width, dash length, gap, and radius. Preview borders in real-time and generate CSS code with one click. Perfect for web layouts, UI design, and button decorations.

Free online HTML filter and extraction tool. Extract plain text from HTML code, filter specific tags, extract links, images, tables and more. Support custom tag filtering, one-click HTML tag removal while preserving desired content.

Free online SQL formatting tool supporting MySQL, PostgreSQL, SQLite, SQL Server, Oracle and more database dialects. Auto format, compress, beautify SQL statements with syntax highlighting and one-click copy.

Free online SQLite database viewer tool. Supports uploading .db/.sqlite files, creating new databases, executing SQL queries, browsing table data, viewing table structure, exporting JSON/CSV and more. Use directly in browser without installation.

Free online tool to view webpage HTML source code. Supports fetching source by URL, uploading local HTML files, and pasting HTML code with formatting and syntax highlighting. Features include syntax highlighting, line numbers, and automatic encoding detection.

Free online YAML editor with formatting, compression, validation, YAML/JSON conversion, Properties conversion, and tree preview. Real-time syntax checking, one-click copy and download, no ads, no installation required.

Free online port scanner supporting single port, port range, and common port groups. Quickly detect target host port status, service types, and response latency for network security assessment and service discovery.

An essential online tool for SEO professionals to automate page reloading. It allows you to continuously monitor real-time ranking fluctuations in search engines and instantly verify the indexing and display results after website updates or code adjustments. By setting custom refresh intervals, it simulates user visits, effectively assisting in website health checks, server response testing, and competitor page monitoring, significantly boosting SEO workflow efficiency.

Free online JSON editor with formatting, compression, validation, tree view browsing, and search. Parse JSON data in real-time with visual tree structure display for efficient editing.

Free online Sitemap detection tool. Fetch and parse sitemap.xml files to extract all URLs. Supports standard Sitemap and Sitemap Index formats, automatic recursive parsing of child sitemaps, and one-click CSV export.

Free online robots.txt crawler rules detection tool. Enter a website domain to quickly fetch and parse the robots.txt file, view search engine crawler rules. Supports Allow/Disallow rule parsing, Crawl-Delay settings, Sitemap extraction, and common crawler-related file detection.

Free online hashtag generator tool that automatically extracts keywords from text to create social media hashtags. Supports custom formatting, case conversion, deduplication, and count limits. Perfect for content marketing and SEO on Instagram, Twitter, TikTok, and other social media platforms.

Free online browser fingerprint detection tool. Detect Canvas fingerprint, WebGL fingerprint, audio fingerprint and more browser fingerprint information. Learn about your browser and device unique identifier to protect online privacy.

Free online subdomain enumeration tool. Quickly discover all subdomains of a target domain based on Certificate Transparency logs (CRT.sh). Supports exporting results and one-click copy for security assessment and asset discovery.

Free online Skeleton Screen generator. Supports article, dashboard, card grid, profile, data table, form, chat, product, hero section, and comments layouts. Customize colors, animations, and preview background, generate ready-to-use HTML+CSS code with one click.

Free online database schema designer tool. Visually design table structures, field types, primary keys, indexes for MySQL and PostgreSQL. Generate CREATE TABLE SQL statements with one click.

Free online regular expression testing tool with real-time matching, syntax highlighting, group capture, and common regex patterns. Test and debug your regular expressions instantly.

Free online API request debugging tool. Supports GET, POST, PUT, DELETE and other HTTP methods. Customize headers and request body, view response status codes, headers and body in real-time to help developers debug APIs quickly.

Free online Nginx and Apache configuration generator. Supports static sites, reverse proxy, load balancing, SSL/HTTPS, security headers and more scenarios. Generate server config files quickly.

Free online JSON Schema generator tool. Input JSON data and automatically generate standard JSON Schema. Supports Draft 2020-12/2019-09/Draft-07/Draft-06/Draft-04 schema versions with customizable options like required fields and additionalProperties. Powered by Monaco Editor for professional code editing experience.

Free online environment variable format converter supporting mutual conversion between .env, YAML, JSON, and Docker formats. Parse env files with one click and quickly convert to target format. Ideal for development configuration management, Docker deployment, CI/CD pipelines, and more.

Free online .gitignore file generator supporting 30+ programming languages and frameworks including Python, Node.js, Go, Rust, Java and more. Select your tech stack to automatically generate a complete .gitignore file. Copy or download with one click.

Free online page speed test tool. Enter a URL to check DNS lookup, TCP connection, TLS handshake, TTFB, download speed, and other core performance metrics. Get a comprehensive score and optimization recommendations to understand your website's performance.

Free online broken link checker tool. Check web page link accessibility in bulk. Support single URL check and batch URL detection, automatically identify broken links, redirects, and timeouts. Provides detailed HTTP status code and response time analysis. Ideal for website SEO optimization,友情链接 checking, and content maintenance.

Free online CSS box shadow generator with real-time preview, multi-layer shadow support, custom color and opacity. Visual controls for offset, blur radius, spread radius, and more. One-click copy CSS code.

Free online CSS gradient background generator. Supports linear, radial, and conic gradients. Customize color stops, angles, and directions. Real-time preview and one-click CSS code copy.

Free online CSS text shadow generator with multi-layer shadow support, real-time visual preview, customizable horizontal offset, vertical offset, blur radius and shadow color, one-click CSS code generation. Perfect for creating stunning text effects.

Free online CSS Flexbox layout generator with visual preview, real-time editing of container and item properties, and automatic CSS code generation.

Free online CSS Grid layout generator. Create grid layouts visually with customizable columns, rows, gaps, and alignment. Real-time preview with ready-to-use CSS code output. Perfect for web layout design, prototyping, and learning CSS Grid.

Free online blob shape generator tool. Generate unique organic SVG shapes in real-time by adjusting parameters like points and randomness. Support custom colors, gradients, stroke styles, and SVG export. Perfect for web design, UI backgrounds, and creative graphic design.

Free online wave separator generator. Supports sine wave, square wave, triangle wave, sawtooth wave and more. Customize colors, amplitude, frequency and generate CSS/SVG code for web decoration, content separation and UI design.

Free online SSL/TLS certificate checker tool. Enter a domain to quickly inspect SSL certificate details including issuer, validity period, Subject Alternative Names (SAN), signature algorithm, public key info, TLS protocol version, and more. Helps you detect expired certificates and misconfigurations.

Free online random user data generator. Create mock user data with name, email, phone, address, company, job title and more. Export to JSON, CSV, SQL, TypeScript, or Excel.

Free online SQL to ER diagram tool. Automatically parse SQL DDL CREATE TABLE statements and generate entity-relationship diagrams. Supports primary/foreign key detection and SVG/PNG export.

Free online Kubernetes YAML configuration file generator. Supports one-click generation of common K8s resources such as Deployment, Service, ConfigMap, Secret, Ingress, Pod, StatefulSet, DaemonSet, Job, and CronJob. Customize image, replica count, environment variables, ports, resource limits, and more to generate standard YAML configurations that can be copied and downloaded.

Free online Redis command lookup tool. Browse and search Redis commands by category, view syntax, time complexity, version, and detailed descriptions. Covers String, Hash, List, Set, Sorted Set, Bitmap, HyperLogLog, Geo, Stream, Pub/Sub, Transaction, Connection, Server, Scripting, Cluster, and Generic commands.

Free online MongoDB query builder. Visually create MongoDB queries with comparison operators, logical combinations, array operations, regex matching, and field existence checks. Preview results in real-time and copy the generated JSON query with one click.

Free online Elasticsearch query generator. Build common DSL queries like match, term, range, bool, and exists through a visual interface. Automatically generates JSON request bodies and cURL commands with one-click copy/download, helping developers quickly write and debug ES queries.

Free online data structure visualization tool. Intuitively understand how arrays, stacks, queues, linked lists, binary trees, binary search trees, and heaps work through animations. Supports insert, delete, search, and traversal operations.

Free online Vim command cheat sheet. Quickly look up common Vim shortcuts by category: cursor movement, insert mode, editing, visual mode, search and replace, file operations, windows and buffers, with search and one-click copy.

Free online regex cheat sheet. Browse common regular expression syntax by character classes, anchors, quantifiers, groups, lookaround assertions, flags, escaping and practical examples. Supports search, one-click copy and live testing.

Free online Kubernetes command cheat sheet, collecting the most commonly used kubectl and Helm commands for daily operations and development. Supports category filtering, keyword search, one-click command copying, and detailed usage examples to help quickly locate and execute K8s operations.

Free online VSCode keyboard shortcut reference covering 70+ common shortcuts for editing, navigation, search, debugging, terminal, Git, and view. Supports Windows/Linux and macOS platforms, category filtering, real-time search, and one-click copy.

Free online IntelliJ IDEA shortcut reference. Supports Windows/Linux and macOS shortcuts. Quickly find and copy commonly used IDEA development shortcuts by category.

Free online Shell command cheat sheet covering common Bash / Zsh commands for Linux / macOS / WSL, including file operations, text processing, system management, network debugging, permissions, compression, and Git, with search, category filtering, one-click copy, and usage examples.

Free online file MD5 fingerprint calculator. Drop in a file to get its fingerprint instantly — large files are processed in milliseconds by reading only a few kilobytes. Batch support and optional full-file MD5. Everything runs locally in your browser; files never leave your device.