The developer's toolbox
A comprehensive collection of free utilities for developers. Code formatting, text processing, image editing, and more. No installation. No signup. No data sent to servers.
Tools for Developers
From code formatting to text processing. We're building the ultimate toolbox for developers.
All Tools
Browse our complete collection of free tools.
Developer Tools
JSON Formatter & Validator
Format, validate, and beautify JSON data instantly
JSON to CSV
Convert JSON data to CSV format
JSON to TypeScript
Generate TypeScript interfaces from JSON
JSON Diff
Compare two JSON objects and highlight differences at field level
JSON to SQL Converter
Convert JSON arrays to SQL INSERT statements with CREATE TABLE definition
JSONPath Tester
Test and evaluate JSONPath expressions
YAML Formatter & Validator
Format, validate, and prettify YAML with error details
YAML to JSON
Convert between YAML and JSON formats
TOML ↔ JSON Converter
Convert between TOML and JSON configuration formats
TOML ↔ YAML Converter
Convert between TOML and YAML configuration formats
XML Formatter
Format and validate XML documents
XPath Tester
Test XPath expressions against XML/HTML
GraphQL Formatter
Format and beautify GraphQL queries, mutations, and SDL
SQL Formatter
Format, minify, and beautify SQL queries
SQL to JSON Converter
Parse SQL INSERT statements and convert to JSON array
Base64 Encoder
Encode and decode Base64 text and files
Base32/Base58/Base85 Encoder
Encode and decode Base32, Base58, and Base85 format text
URL Encode/Decode
Encode or decode URL strings with component-only option
URL Parser
Parse and analyze URL components
Hash Generator
Generate MD5, SHA-1, SHA-256, SHA-512 hashes
Advanced Hash Generator
Generate hashes with SHA3, RIPEMD160, CRC32, xxHash and more
HMAC Generator
Generate HMAC signatures with SHA algorithms
Hex Encoder/Decoder
Encode text to hex or decode hex to text with multiple format options
HTML Encoder
Encode and decode HTML entities
Regex Tester
Test regular expressions with live preview
Regex Cheatsheet
Interactive regex syntax quick reference with examples
Text Diff / Code Diff
Compare two texts and highlight differences (added, removed, modified lines)
Text Escape/Unescape Converter
Escape or unescape text sequences for programming
JavaScript Minifier
Minify JavaScript code by removing whitespace and comments
CSS Minifier
Minify CSS code by removing whitespace and optimizing values
HTML Minifier
Minify HTML by removing whitespace, comments, and optional tags
TypeScript to JavaScript Transpiler
Convert TypeScript/TSX code to JavaScript in the browser
Markdown to HTML
Convert Markdown syntax to HTML
JWT Decoder
Decode JSON Web Tokens to view header and payload
JWT Encoder & Signer
Encode and sign JWT tokens with HMAC algorithms
Bcrypt Hash Generator & Verifier
Generate and verify bcrypt password hashes with adjustable cost factor
Password Strength Analyzer
Analyze password strength using zxcvbn algorithm
AES Encryption / Decryption
Encrypt and decrypt text using AES-256-GCM encryption
RSA Key Pair Generator
Generate RSA public/private key pairs in PEM format
HTTP Request Builder & Tester
Build and test HTTP requests with custom headers, body, and authentication
HTTP Status Codes Reference
Complete HTTP status code reference with descriptions, RFC links, and usage examples
cURL Command Generator
Generate cURL commands from HTTP request parameters
CORS Checker
Check CORS configuration and analyze preflight requests
WebSocket Tester
Test WebSocket connections with message sending and receiving
DNS Lookup
Query DNS records using DNS-over-HTTPS
IP Lookup
Query IP address geolocation, ISP, and ASN information
UUID Generator
Generate random UUIDs and GUIDs
UUID Validator
Validate UUID format and generate random UUIDs
UUID / NanoID / ULID Generator
Generate UUID, NanoID, and ULID unique identifiers
Slug Generator
Generate URL-friendly slugs from text
Number Base Converter
Convert numbers between binary, decimal, hex and other bases
Timestamp Converter
Convert between Unix timestamps and dates
CRC32 / Checksum Generator
Calculate CRC32, CRC32C and Adler32 checksums
MIME Checker
Check and validate MIME types
User Agent Parser
Parse user agent strings to identify browsers and OS
Cron Parser
Parse and validate cron job expressions
CIDR Calculator
Calculate network ranges and subnet masks
Chmod Calculator
Calculate Linux file permissions in numeric and symbolic notation
ASCII / Unicode Lookup
Look up ASCII and Unicode characters, find character codes, HTML entities, CSS escapes
Git Cheatsheet
Common Git commands quick reference with examples
Designer Tools
Aspect Ratio Calculator
Calculate and scale aspect ratios for images and videos
Border Radius Generator
Generate CSS border-radius values with visual preview
Box Shadow Generator
Generate beautiful CSS box shadows with interactive controls
Color Converter
Convert between HEX, RGB, and HSL color formats
Contrast Checker
Check color contrast ratios for accessibility compliance
Favicon Generator
Generate favicons for websites from any image
Glassmorphism Generator
Create modern glassmorphism UI effects
Gradient Generator
Create stunning CSS gradients with visual editor
CSS Grid Generator
Generate CSS Grid layouts with visual builder
CSS Filter Playground
Experiment with CSS filters interactively
Flexbox Playground
Visual builder for CSS Flexbox layouts
Font Converter
Convert between font formats
Image Converter
Convert images between different formats
Image Resizer
Resize images to specific dimensions
Line Height Calculator
Calculate optimal line height for better readability
Image to Base64
Convert images to Base64 data URLs for embedding
Color Palette Extractor
Extract color palettes from images automatically
Metadata Viewer
View and edit file metadata
SVG Optimizer
Optimize and minify SVG files
Writer Tools
Case Converter
Convert text to uppercase, lowercase, title case, and more
Citation Generator
Generate citations in APA, MLA, and Chicago formats
Duplicate Remover
Find and remove duplicate lines from text
Headline Analyzer
Analyze headlines for SEO and engagement
Lorem Ipsum Generator
Generate dummy text for your designs and prototypes
Markdown Preview
Live markdown editor with instant preview
Passive Voice Detector
Detect passive voice constructions in text
Random Picker
Randomly select items from a list
Reading Level Checker
Check the reading level of your text
Reading Time Calculator
Estimate reading time for any text
Sentence Length Analyzer
Analyze sentence length distribution in text
Sort Lines
Sort lines of text alphabetically or numerically
Text Summarizer
Automatically summarize long text into key points
Whitespace Remover
Remove extra spaces and tabs from text
Word Counter
Count words, characters, sentences, and reading time
Word Frequency Counter
Count word frequency in text
Calculator Tools
Age Calculator
Calculate exact age from birthdate
Base Converter
Convert between binary, decimal, hex, and octal
BMI Calculator
Calculate Body Mass Index from height and weight
Credit Card Validator
Validate credit card numbers using Luhn algorithm
Date Difference Calculator
Calculate days between two dates
Discount Calculator
Calculate discounted prices and savings
Fraction Calculator
Perform arithmetic operations with fractions
Hash Generator
Generate various hash functions from text
Loan Calculator
Calculate loan payments and interest
Percentage Calculator
Calculate percentages, increases, and decreases easily
Password Generator
Generate secure random passwords with custom options
Quadratic Equation Solver
Solve quadratic equations and find roots
Random Number Generator
Generate random numbers in a range
Number to Words
Convert numbers to their written form in English
Text Diff
Compare two texts and see differences highlighted
Time Zone Converter
Convert times between different zones
Tip Calculator
Calculate tips and split bills
Roman Numeral Converter
Convert between Roman numerals and Arabic numbers
Unit Converter
Convert length, weight, temperature, and data storage units
Office Tools
Batch Rename
Rename multiple files at once with patterns
Business Card Maker
Design professional business cards with customizable templates
Compress PDF
Reduce PDF file size while maintaining quality
Decrypt PDF
Remove password protection from PDFs
Encrypt PDF
Add password protection to PDFs
Extract PDF Images
Extract all images from a PDF document
Extract PDF Pages
Extract specific pages from a PDF
File Info
View detailed file information and metadata
CSS Filter Playground
Experiment with CSS filters interactively
Flexbox Playground
Visual builder for CSS Flexbox layouts
Font Converter
Convert between font formats
Invoice Generator
Create professional invoices with automatic calculations
Merge PDFs
Combine multiple PDF files into a single document
Metadata Viewer
View and edit file metadata
PDF to Images
Convert PDF pages to image files
PDF to Text
Extract text content from PDF documents
PDF Watermark
Add watermarks to PDF pages
QR Code Generator
Generate QR codes for URLs, text, WiFi, and vCard
Reorder PDF Pages
Rearrange pages in a PDF document
Resize Image
Resize images to specific dimensions
Rotate PDF
Rotate pages in a PDF document
Split PDF
Split a PDF into separate files by page ranges
Why 9kit?
Built for developers who value speed, privacy, and simplicity.
Lightning Fast
Zero latency. All tools run instantly in your browser with no server delays.
100% Private
Your data never leaves your device. No tracking, no logs, no data collection.
100+ Tools
A comprehensive collection of tools for developers, from code formatting to text processing.
One kit. All your tools.
Our vision is simple: create the most comprehensive, privacy-focused toolbox for developers.