Developer Guides
Step-by-step tutorials for common developer tasks. Each guide links to a free tool you can use right away.
How to Format JSON Online
Format, validate, and beautify JSON instantly in your browser. Free JSON formatter with syntax highlighting, error detec...
Read guide →How to Encode & Decode Base64
Encode text to Base64 or decode Base64 strings instantly. Free online tool with UTF-8 support, file encoding, and URL-sa...
Read guide →How to Generate UUID Online
Generate UUID v4 instantly in your browser. Bulk generate, copy to clipboard, and use in your code. Free UUID/GUID gener...
Read guide →How to Test an API Online
Send HTTP requests and test REST APIs directly from your browser. Free Postman alternative with GET, POST, PUT, DELETE s...
Read guide →How to Convert CSV to JSON
Convert CSV data to JSON format instantly. Free online tool that handles headers, custom delimiters, and large files. No...
Read guide →How to Generate a Secure Password
Generate cryptographically secure passwords instantly. Customize length, characters, and complexity. Free password gener...
Read guide →How to Create a QR Code Online
Generate QR codes for URLs, text, WiFi, and more. Free QR code generator with customizable size, colors, and instant PNG...
Read guide →How to Decode a JWT Token
Decode and inspect JWT tokens instantly. View header, payload, claims, and expiration. Free JWT decoder with signature v...
Read guide →How to Test Regex Online
Test and debug regular expressions in real-time. Free regex tester with match highlighting, capture groups, and cheat sh...
Read guide →How to Parse Cron Expressions
Build and understand cron schedule expressions visually. Free cron parser that shows next run times, explains syntax in ...
Read guide →How to Generate Hash Online
Generate MD5, SHA-1, SHA-256, and SHA-512 hashes instantly. Free hash generator for text and files. Compare hashes to ve...
Read guide →How to Generate a Color Palette
Create beautiful color palettes for your designs. Generate harmonious colors, extract palettes from images, and export i...
Read guide →How to Build a CSS Grid Layout
Create CSS Grid layouts visually with a drag-and-drop builder. Generate clean CSS code for responsive grid layouts. No C...
Read guide →How to Preview Markdown Online
Write and preview Markdown in real-time. Free online editor with live preview, syntax highlighting, and export to HTML. ...
Read guide →How to Minify CSS Online
Minify CSS files instantly to reduce file size and improve page load speed. Free online CSS minifier with whitespace rem...
Read guide →How to Convert JSON to XML
Convert JSON data to XML format instantly. Free online converter that handles nested objects, arrays, and preserves data...
Read guide →How to Generate CSS Gradients
Create beautiful CSS gradients visually. Free gradient generator with linear, radial, and conic gradients. Pick colors, ...
Read guide →How to Encode & Decode URLs Online
Encode special characters in URLs or decode percent-encoded strings instantly. Free URL encoder/decoder with UTF-8 suppo...
Read guide →How to Format SQL Online
Format and beautify SQL queries instantly. Free SQL formatter with syntax highlighting, indentation, and support for MyS...
Read guide →How to Convert HTML to Markdown
Convert HTML to clean Markdown instantly. Free tool that transforms HTML tags into Markdown syntax — headings, links, im...
Read guide →How to Generate Lorem Ipsum
Generate lorem ipsum placeholder text for designs and mockups. Choose paragraphs, sentences, or words. Free tool with in...
Read guide →How to Diff JSON Online
Compare two JSON objects side by side and instantly see additions, deletions, and changes. Free online JSON diff tool — ...
Read guide →How to Convert JSON to CSV
Convert JSON arrays to CSV format instantly. Supports nested objects, custom delimiters, and header detection. Free tool...
Read guide →How to Generate a Favicon
Create favicons from text, emoji, or image uploads. Generate all sizes (16x16 to 512x512) with one click. Free online to...
Read guide →How to Build Docker Compose
Generate docker-compose.yml files visually. Add services, configure ports, volumes, and environment variables. Free tool...
Read guide →How to Compress Images Online
Compress JPEG, PNG, and WebP images without losing quality. Reduce file size by up to 80% in your browser. Free — no upl...
Read guide →How to Optimize SVG Files
Clean and optimize SVG files to reduce file size. Remove metadata, simplify paths, and minify markup. Free browser-based...
Read guide →How to Validate JSON Schema
Validate JSON data against a JSON Schema definition. Check types, required fields, patterns, and constraints. Free onlin...
Read guide →How to Convert XML to JSON
Convert XML data to JSON format instantly. Handles attributes, namespaces, and nested elements. Free browser-based conve...
Read guide →How to Generate Mock Data Online
Generate realistic mock data for APIs, databases, and testing. Names, emails, addresses, dates — all fake but realistic....
Read guide →How to Build a Flexbox Layout
Create CSS Flexbox layouts visually. Adjust direction, alignment, wrapping, and gaps with live preview. Generate clean C...
Read guide →How to Convert Image to Base64
Convert images (PNG, JPG, SVG, GIF, WebP) to Base64 data URIs instantly. Embed images directly in HTML, CSS, or JSON wit...
Read guide →How to Calculate Chmod Permissions
Calculate Linux file permissions with an interactive chmod calculator. Convert between numeric (755) and symbolic (rwxr-...
Read guide →How to Generate Placeholder Images
Generate custom placeholder images for mockups and prototypes instantly. Set size, color, text, and format. Free placeho...
Read guide →How to Build CSS Box Shadow
Create CSS box shadows visually with a live preview. Adjust offset, blur, spread, color, and inset. Copy production-read...
Read guide →How to Convert cURL to Code
Convert cURL commands to Python, JavaScript, Go, PHP, and more. Paste a curl command, get production-ready code. Free on...
Read guide →How to Resize an Image Online
Resize images to any dimension instantly in your browser. Maintain aspect ratio, set exact pixels, or resize by percenta...
Read guide →How to Generate ASCII Art Online
Convert text to ASCII art instantly. Choose from 20+ fonts, preview in real-time, and copy to clipboard. Free ASCII art ...
Read guide →How to Build CSS Animations
Create CSS keyframe animations visually. Adjust timing, easing, and properties with a live preview. Free CSS animation g...
Read guide →How to Test WebSocket Connections
Connect to any WebSocket server, send messages, and inspect responses in real-time. Free browser-based WebSocket testing...
Read guide →How to Generate Meta Tags for SEO
Generate SEO-optimized meta tags for your website. Preview how your page appears in Google, Facebook, and Twitter. Free ...
Read guide →How to Generate CSS Border Radius
Create CSS border-radius values visually. Adjust each corner independently, preview live, and copy production-ready CSS....
Read guide →How to Convert Text Case Online
Convert text between uppercase, lowercase, title case, sentence case, camelCase, snake_case, and more. Free online text ...
Read guide →How to Generate URL Slugs
Convert any text into clean, SEO-friendly URL slugs. Handles special characters, accents, and multiple languages. Free s...
Read guide →How to Parse & Analyze HTTP Headers
Parse, inspect, and analyze HTTP response headers from any URL. Check security headers, caching rules, and CORS configur...
Read guide →How to Convert JSON to Types
Generate TypeScript interfaces, Go structs, Rust types, and more from any JSON data. Free online JSON to types converter...
Read guide →How to Build a Markdown Table
Create perfectly formatted Markdown tables with an interactive editor. Set columns, enter data, align text, and copy the...
Read guide →How to Diff Text Online
Compare two texts side-by-side and find every difference instantly. Free online diff checker with line-by-line highlight...
Read guide →How to Convert YAML to JSON
Convert YAML to JSON and JSON to YAML instantly in your browser. Free online converter with syntax validation, error hig...
Read guide →How to Generate Unix Timestamps
Generate Unix timestamps, convert epoch to human-readable dates, and batch-convert timestamps instantly in your browser....
Read guide →How to Convert Number Bases Online
Convert numbers between binary, octal, decimal, and hexadecimal instantly. Free online base converter with step-by-step ...
Read guide →How to Build Git Commands
Build complex Git commands visually without memorizing flags. Select operations, options, and parameters from a visual i...
Read guide →How to Count Words Online
Count words, characters, sentences, and paragraphs in your text instantly. Free online word counter with reading time es...
Read guide →How to Generate Color Codes Online
Pick any color and get its HEX, RGB, HSL, and CMYK codes instantly. Free online color code generator with palette sugges...
Read guide →How to Escape HTML Online
Escape and unescape HTML entities instantly. Convert special characters like <, >, &, and quotes to their HTML entity eq...
Read guide →How to Decode & Test JWT Tokens
Decode, inspect, and validate JSON Web Tokens instantly. View header, payload, and signature. Free JWT debugger with exp...
Read guide →How to Convert Pixels to REM
Convert pixel values to REM units instantly. Free PX to REM calculator with customizable base font size, bulk conversion...
Read guide →How to Validate Email Addresses
Validate email addresses instantly with regex, format checks, and common typo detection. Free online email validator for...
Read guide →How to Generate Lorem Ipsum Text
Generate lorem ipsum placeholder text for web designs, mockups, and prototypes. Choose paragraphs, sentences, or words —...
Read guide →How to Test GraphQL Queries Online
Test GraphQL queries, mutations, and subscriptions against any endpoint. Free online GraphQL playground with syntax high...
Read guide →How to Build a Responsive Layout
Build responsive CSS layouts with grid and flexbox. Free visual layout builder with breakpoint preview, code export, and...
Read guide →How to Calculate Color Contrast Ratio
Check color contrast ratios for WCAG 2.1 accessibility compliance. Free online contrast checker with AA/AAA ratings, col...
Read guide →How to Generate HMAC
Generate HMAC signatures using SHA-256, SHA-512, MD5, and more. Free online HMAC generator for API authentication, webho...
Read guide →How to Query JSON with JSONPath
Extract data from JSON using JSONPath expressions. Free online evaluator with syntax highlighting, path suggestions, and...
Read guide →How to Generate Fake Test Data
Generate realistic fake data for testing: names, emails, addresses, phone numbers, and more. Free mock data generator wi...
Read guide →How to Generate JWT Tokens
Create and sign JWT tokens with custom claims, algorithms, and expiration. Free online JWT generator with HS256, RS256 s...
Read guide →How to Count AI Tokens
Count tokens for GPT, Claude, and other LLM APIs instantly. Estimate API costs, check context window limits, and optimiz...
Read guide →How to Escape & Unescape Strings
Escape and unescape strings for JSON, HTML, URLs, SQL, regex, and more. Free online tool that handles special characters...
Read guide →How to Convert CSS Units
Convert between CSS units instantly: px, rem, em, vh, vw, %, pt, and more. Free online converter with responsive design ...
Read guide →How to Calculate AI API Costs
Compare pricing across OpenAI, Anthropic, Google, and Meta models. Calculate per-request and monthly API costs instantly...
Read guide →How to Preview HTML Online
Live HTML/CSS/JS editor with instant preview. Test code snippets, prototype page layouts, and debug rendering issues in ...
Read guide →How to Look Up HTTP Status Codes
Search and understand all HTTP status codes from 1xx to 5xx. Get clear explanations, common use cases, and troubleshooti...
Read guide →How to Convert Markdown to HTML
Convert Markdown syntax to clean, semantic HTML output instantly. Preview the rendered result and copy production-ready ...
Read guide →How to Encode & Decode Base32
Encode text to Base32 or decode Base32 strings instantly. Free online tool following RFC 4648. No data leaves your brows...
Read guide →How to Simulate Color Blindness
Test your designs for color blindness. Simulate protanopia, deuteranopia, tritanopia, and more. Free accessibility testi...
Read guide →How to Diff Environment Files
Compare two .env files and find differences instantly. Free environment variable diff tool for developers. Identify miss...
Read guide →How to Edit Environment Files
Edit .env files with a user-friendly interface. Add, modify, and delete environment variables. Free dotenv editor for de...
Read guide →How to Batch Convert Epoch Timestamps
Convert multiple epoch timestamps at once. Batch convert Unix time to human-readable dates and vice versa. Free develope...
Read guide →How to Sort JSON Keys
Sort JSON object keys alphabetically or reverse. Recursively sort nested objects. Free online JSON key sorter for develo...
Read guide →How to View OpenAPI Specifications
View and explore OpenAPI (Swagger) specifications online. Free OpenAPI viewer for REST API documentation. Supports OpenA...
Read guide →How to Build Effective AI Prompts
Craft better prompts for AI models. Free AI prompt builder with templates and best practices for ChatGPT, Claude, and ot...
Read guide →How to Find & Use Regex Patterns
Browse and use common regex patterns. Free regex library with ready-to-use patterns for emails, URLs, phone numbers, and...
Read guide →How to Convert Regex to Code
Convert regex patterns to code in JavaScript, Python, Java, and more. Free regex code generator with ready-to-use snippe...
Read guide →How to Convert SQL to Code
Convert SQL queries to code in JavaScript, Python, PHP, and more. Free SQL to code generator with ORM and raw query supp...
Read guide →How to Test Tailwind CSS
Experiment with Tailwind CSS classes in a live playground. Free Tailwind playground with instant preview and IntelliSens...
Read guide →How to Convert Text to Binary
Convert text to binary and back. Free online text to binary converter with ASCII, UTF-8 support. Instant translation bot...
Read guide →How to Lookup Unicode Characters
Search and explore Unicode characters. Free Unicode lookup tool with code points, HTML entities, and character informati...
Read guide →How to Choose a Tech Stack
Find the perfect tech stack for your project. Interactive selector with recommendations based on your needs. Free develo...
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