dev tools
Format, encode, generate, convert — all in your browser. Your data never leaves your machine.
// AI & LLM Utilities
AI Cost Calculator
Free online AI cost calculator. Estimate API costs for GPT-5, Claude, Gemini, Llama 4, and DeepSeek. …
AI Model Comparison Table
Free interactive AI model comparison table. Compare context windows, pricing, benchmarks, and speeds …
AI Token Counter
Free online AI token counter. Estimate token counts for GPT-5, Claude, Gemini, Llama and more. …
Chunking Preview Tool
Free online text chunking tool for RAG pipelines. Split text by tokens, sentences, or paragraphs …
JSON Schema Generator for Function Calling
Free online JSON schema generator for AI function calling. Build tool schemas for OpenAI and Claude …
Prompt Diff / A/B Viewer
Free online prompt diff tool. Compare two prompts side by side with highlighted differences. Track …
Prompt Template Library
Free curated prompt templates for developers. Copy-paste prompts for coding, debugging, writing, …
Structured Output Tester
Free online structured output tester. Validate JSON schemas, generate example responses, and create …
System Prompt Builder
Free online system prompt builder. Create structured system prompts for ChatGPT, Claude, and other …
Text Similarity Analyzer
Free online text similarity analyzer. Compare two texts using TF-IDF and cosine similarity. …
// Formatters
CSS Beautifier / Minifier
Free online CSS beautifier and minifier. Format and compress CSS code instantly in your browser. No …
HTML Beautifier / Minifier
Free online HTML beautifier and minifier. Format, beautify and minify HTML code instantly in your …
JavaScript Beautifier / Minifier
Free online JavaScript beautifier and minifier. Format and compress JS code instantly in your …
JSON Formatter & Validator
Free online JSON formatter and validator. Beautify, minify and validate JSON instantly in your …
SQL Formatter
Free online SQL formatter. Beautify and format SQL queries instantly in your browser. No signup …
XML Formatter & Validator
Free online XML formatter and validator. Beautify and validate XML instantly in your browser. No …
YAML Validator
Free online YAML validator and syntax checker. Validate YAML files instantly in your browser — …
// Encoders
Base64 Encode / Decode
Free online Base64 encoder and decoder. Convert text to Base64 and back instantly in your browser. …
HTML Entity Encode/Decode
Free online HTML entity encoder and decoder. Convert special characters to HTML entities and back …
JWT Decoder
Free online JWT decoder. Decode and inspect JSON Web Token header and payload instantly. Check …
JWT Generator
Free online JWT generator. Sign JSON Web Tokens with HS256, HS384 or HS512 in your browser. Add …
Morse Code Translator
Free online Morse code translator. Convert text to Morse code and Morse code to text instantly in …
Unicode Escape/Unescape
Free online Unicode escape and unescape tool. Convert text to \uXXXX escape sequences and back …
URL Encode / Decode
Free online URL encoder and decoder. Percent-encode special characters and decode %20, %2F, %3D, and …
// Generators
.gitignore Generator
Free .gitignore generator for 50+ languages and frameworks. Build a .gitignore file for Node.js, …
Cron Expression Builder
Free online cron expression builder. Generate and understand cron schedules visually. Human-readable …
Favicon Generator
Free online favicon generator. Create favicons from text or emoji instantly in your browser. …
Lorem Ipsum Generator
Free online Lorem Ipsum generator. Generate placeholder text paragraphs, sentences, or words …
Meta Tags Generator
Free online meta tags generator. Create HTML meta tags, Open Graph tags, and Twitter Card tags …
Password Generator
Free online password generator. Create strong, random passwords instantly in your browser. …
QR Code Generator
Free online QR code generator. Create QR codes for URLs, text, WiFi, and more instantly in your …
robots.txt Generator
Free online robots.txt generator. Build and customize your robots.txt file instantly in your …
UUID Generator
Free online UUID generator. Generate random UUIDs (v4) instantly in your browser. Bulk generation, …
// Converters
Color Converter
Free online color converter. Convert between HEX, RGB, HSL color formats instantly. Visual color …
HTML to Markdown Converter
Free online HTML to Markdown converter. Convert HTML code to clean Markdown syntax instantly in your …
JSON to CSV Converter
Free online JSON to CSV converter. Convert JSON arrays to CSV and CSV to JSON instantly in your …
JSON to YAML Converter
Free online JSON to YAML converter. Convert between JSON and YAML formats instantly in your browser. …
Markdown to HTML Converter
Free online Markdown to HTML converter. Convert Markdown syntax to HTML code instantly in your …
Number Base Converter
Free online number base converter. Convert between binary, octal, decimal, and hexadecimal instantly …
Unix Timestamp Converter
Free online Unix timestamp converter. Convert timestamps to human-readable dates and back. Supports …
YAML to TOML Converter
Free online YAML to TOML converter. Convert between YAML and TOML formats instantly in your browser. …
// Text Utilities
Case Converter
Free online case converter. Instantly convert text to camelCase, snake_case, PascalCase, kebab-case, …
chmod Calculator
Free online chmod calculator. Convert between numeric and symbolic Unix file permissions instantly …
Diff Checker
Free online diff checker. Compare two texts side by side with highlighted differences. Find changes …
Hash Generator
Free online hash generator. Generate MD5, SHA-1, SHA-256, and SHA-512 hashes instantly in your …
Regex Tester
Free online regex tester. Test regular expressions with real-time match highlighting. Supports …
Word & Character Counter
Free online word and character counter. Count words, characters, sentences, and paragraphs …
// from the blog
Understanding Unix Timestamps
Learn what Unix timestamps are, how they work, and how to convert them in different programming languages.
MD5 vs SHA-256: Security Comparison
Compare MD5 and SHA-256 hash algorithms. Learn the differences in security, speed, and when to use each for your …
JSON vs YAML: When to Use Which
Compare JSON and YAML data formats. Learn the differences, pros, cons, and when to use each format in your projects.
Regex Cheatsheet for Developers
Complete regular expression cheatsheet. Quick reference for regex syntax, character classes, quantifiers, anchors, and …
What is JWT and How to Decode It
Learn what JSON Web Tokens are, how they work, and how to decode them. Understand JWT structure, claims, and common use …