All the tools

135+ free developer tools — everything runs in your browser

Encoders & Decoders

20
Base64 Encoder / Decoder
Encode & decode Base64 strings
Popular
URL Encoder / Decoder
Encode & decode URL components
HTML Entity Encoder
Encode & decode HTML entities
JWT Decoder & Verifier
Decode & verify JWT tokens with signature check
Popular
Hash Generator
MD5, SHA-1, SHA-256 & SHA-512 hashes
Base64 Image Encoder
Convert images to Base64 data URIs
Base64 Image Decoder
Decode Base64 strings back into images
GZIP Compress / Decompress
Compress & decompress text with GZIP
Text Escape / Unescape
Escape & unescape JSON, HTML, URL, XML & more
Backslash Escape / Unescape
Escape & unescape backslash sequences per language
Bcrypt Hash Generator
Hash & verify passwords with PBKDF2-SHA256
HMAC Generator
Generate HMAC-SHA256/384/512 message digests
AES Encrypt / Decrypt
Encrypt & decrypt text with AES-256-GCM
Popular
PDF Signature Checker
Check PDF files for digital signatures
Base32 Encoder / Decoder
Encode & decode Base32 strings (RFC 4648)
Punycode Encoder / Decoder
Convert internationalized domain names to Punycode
Morse Code Translator
Translate text to Morse code & back with audio
Hex String Encoder / Decoder
Convert text to hex strings & back
PBKDF2 Key Generator
Derive cryptographic keys with PBKDF2
Base58 Encoder / Decoder
Encode & decode Base58 (Bitcoin & Flickr alphabets)

Formatters & Linters

19
JSON Formatter
Format, validate & minify JSON
Popular
SQL Formatter
Beautify & indent SQL queries
Markdown Previewer
Write Markdown, see live HTML preview
Code Minifier
Minify JS, CSS & HTML code
Diff Checker
Compare two texts, highlight changes
Popular
Regex Tester
Test regular expressions with live matching
XML Formatter
Format, validate & minify XML
CSS Formatter / Minifier
Beautify or minify CSS stylesheets
HTML Formatter / Minifier
Beautify or minify HTML documents
JSONPath Tester
Test JSONPath expressions on JSON data
JSON Schema Validator
Validate JSON data against a JSON Schema
HTML WYSIWYG Editor
Rich text editor with live HTML output
JSON Diff
Deep compare two JSON objects & highlight differences
YAML Formatter
Format & prettify YAML documents
Nginx Config Formatter
Format & beautify Nginx configuration files
.env File Formatter
Sort, group & validate .env files
GraphQL Formatter
Format & prettify GraphQL queries
Dockerfile Linter
Lint Dockerfiles for best practices
Markdown Linter
Format & lint Markdown documents

Generators

35
Password Generator
Strong, random, secure passwords
Popular
UUID Generator
Generate random UUID v4 identifiers
Lorem Ipsum Generator
Generate placeholder text
Random Name Generator
Names, usernames & businesses
Slug Generator
Convert text to URL-friendly slugs
CSS Gradient Generator
Create CSS gradient code visually
Cron Expression Parser
Build & explain cron schedules
QR Code Generator
Generate QR codes from text or URLs
Popular
RSA Key Pair Generator
Generate RSA public/private key pairs
Chmod Calculator
Calculate Linux file permission codes
Markdown Table Generator
Build Markdown tables visually
Token / API Key Generator
Generate random tokens & API keys
Popular
ULID Generator
Generate sortable ULID identifiers
BIP39 Passphrase Generator
Generate memorable mnemonic passphrases
OTP / TOTP Generator
Generate time-based one-time passwords
Basic Auth Header Generator
Generate & decode HTTP Basic Auth headers
Open Graph Meta Generator
Generate OG & Twitter Card meta tags
Random Port Generator
Generate random port numbers with range options
WiFi QR Code Generator
Generate QR codes for WiFi network connections
SVG Placeholder Generator
Create SVG placeholder images with custom dimensions
Camera Recorder
Capture screenshots & record video from your camera
MAC Address Generator
Generate random MAC addresses with format options
IPv6 ULA Generator
Generate RFC 4193 Unique Local IPv6 addresses
SSH Key Generator
Generate RSA & ECDSA key pairs in PEM format
CORS Header Generator
Generate CORS config for Express, Nginx & Apache
Placeholder Data Generator
Generate fake names, emails, addresses & more
Sitemap XML Generator
Generate XML sitemaps from URL lists
CSS Box Shadow Generator
Visual box shadow builder with live preview
Flexbox Playground
Interactive CSS Flexbox layout builder
CSS Grid Generator
Visual CSS Grid layout builder
Color Palette Generator
Generate harmonious color palettes from a seed color
JWT Token Generator
Build & sign JWT tokens with HMAC
robots.txt Generator
Visual robots.txt builder with presets
.htaccess Generator
Generate common .htaccess rules
Barcode Generator
Generate Code 128 barcodes as SVG/PNG

Converters

30
HEX ↔ RGB Converter
Web color code converter
Color Picker & Converter
Pick colors, convert HEX / RGB / HSL
Popular
Timestamp Converter
Unix timestamp ↔ human-readable date
CSV to JSON Converter
Convert between CSV & JSON formats
JSON ↔ YAML Converter
Convert between JSON & YAML formats
Popular
XML ↔ JSON Converter
Convert between XML & JSON formats
JSON to TypeScript
Generate TypeScript interfaces from JSON
Popular
HTML to JSX Converter
Convert HTML markup to React JSX
Popular
Number Base Converter
Convert between binary, octal, decimal & hex
TOML ↔ JSON Converter
Convert between TOML & JSON formats
SQL to MongoDB Converter
Convert SQL queries to MongoDB syntax
Epoch Batch Converter
Bulk convert timestamps & dates
Docker Run → Compose
Convert docker run commands to compose YAML
Text ↔ Binary / Hex
Convert text to binary or hexadecimal
Roman Numeral Converter
Convert between decimal numbers & Roman numerals
Case Converter
Convert text between camelCase, snake_case, kebab-case & more
Text to NATO Alphabet
Convert text to NATO phonetic alphabet
Text to Unicode
Convert text to Unicode code points & back
YAML ↔ TOML Converter
Convert between YAML & TOML formats
List Converter
Convert & transform lists with separators & options
Markdown to HTML
Convert Markdown to HTML code
Temperature Converter
Convert between Celsius, Fahrenheit & Kelvin
WebP Image Converter
Convert PNG/JPG images to WebP format
SVG to PNG Converter
Convert SVG to PNG with custom dimensions
Charset Converter
View text encoding in UTF-8, UTF-16 & Latin-1
JSON to Go Struct
Generate Go struct definitions from JSON
JSON to CSV Converter
Convert JSON arrays to CSV with flattening
Image Cropper & Resizer
Crop & resize images with format conversion
Favicon Generator
Generate favicons in all sizes from an image
Color Blindness Simulator
Simulate color vision deficiencies

Text Tools

31
Word Counter
Words, chars, sentences & more
Character Counter
Count chars for social platforms
HTTP Status Code Reference
Searchable HTTP status code lookup
ASCII Art Generator
Generate text art in multiple font styles
IP Subnet Calculator
Calculate subnet ranges & network info
Regex Cheat Sheet
Interactive searchable regex reference
Password Strength Analyzer
Analyze password entropy & crack time
Math Expression Evaluator
Evaluate math expressions safely
ETA Calculator
Estimate time remaining for tasks
Percentage Calculator
Calculate percentages & changes
MIME Type Lookup
Search file extensions & MIME types
User Agent Parser
Parse browser & OS from user agent strings
Phone Number Parser
Parse & format international phone numbers
IPv4 Range Expander
Expand CIDR ranges to IP addresses
URL Parser
Parse & inspect URL components
Device Information
View browser, OS & device details
Keycode Info
Press any key to see its keycode & properties
Outlook Safelink Decoder
Decode Outlook Safe Links to original URLs
Git Cheatsheet
Searchable reference of common Git commands
Email Normalizer
Normalize email addresses for deduplication
IPv4 Address Converter
Convert IPv4 between decimal, binary, hex & octal
MAC Address Lookup
Look up vendor from MAC address OUI prefix
Chronometer
Stopwatch with lap times & millisecond precision
Benchmark Builder
Benchmark JavaScript code snippets & compare performance
Emoji Picker
Browse & copy emojis by category
String Obfuscator
Obfuscate text with ROT13, homoglyphs & more
Numeronym Generator
Generate numeronyms like i18n, l10n, a11y
IBAN Validator
Validate & parse International Bank Account Numbers
cURL Command Builder
Build cURL commands from a visual form
HTTP Header Parser
Parse & explain HTTP headers
Aspect Ratio Calculator
Calculate & visualize aspect ratios

Free Online Developer Tools — No Signup Required

Konvertio is a free collection of 135+ online developer tools built for software engineers, web developers, DevOps engineers, and IT professionals. Every tool runs entirely in your browser — your data never leaves your device.

Encoders & Decoders: Base64, URL encoder, JWT decoder, AES encryption, HMAC, hash generators (MD5, SHA-256, SHA-512), Punycode, Morse code, and more.

Formatters & Linters: JSON formatter & validator, SQL formatter, CSS beautifier, XML formatter, YAML formatter, GraphQL formatter, Nginx config formatter, and Dockerfile linter.

Generators: Password generator, UUID generator, QR code maker, Lorem Ipsum, cron expressions, color palettes, SSH key generator, barcode generator, OTP codes, and placeholder data.

Converters: JSON ↔ YAML, JSON → TypeScript, HTML → JSX, CSV ↔ JSON, Markdown → HTML, YAML ↔ TOML, Docker Compose generator, image format converters, and unit converters.

Text & Utility Tools: Diff checker, regex tester, word counter, HTTP status codes reference, user agent parser, Git cheatsheet, cURL builder, and many more productivity tools for developers.