AppSvc online developer toolbox

Kr3 DevTools

Fast local utilities for encoding, JSON, hashes, timestamps, UUIDs, QR codes, text processing, and more.

All developer tools

Data

Format, convert, validate, and generate structured data for development workflows.

Batch Image CropBatch crop photos to a target size with cover crop or centered padding.
Batch JSON FormatterFormat or minify multiple JSON documents locally.
Code to ImageRender code into a shareable SVG image locally.
Color ExtractionExtract a simple dominant palette from an image locally.
CSS Formatter / CompressorFormat or compress CSS locally.
CSV Table to SQLConvert a CSV table into SQL INSERT statements locally.
HTML FormatterFormat HTML markup locally.
HTML Symbols ReferenceReference common HTML entities locally.
HTML Table to Markdown TableConvert HTML tables into Markdown tables locally.
HTML to JSXConvert common HTML attributes into JSX syntax locally.
HTML to SQLConvert an HTML table into SQL INSERT statements locally.
Image CompressorCompress images locally with Squoosh-style quality and resize controls.
Image CropCrop local images with free selection or common photo presets.
Image to IconConvert an image into icon-sized PNG and ICO files locally.
JavaScript Formatter / CompressorFormat or compress JavaScript locally.
JSON DiffFormat two JSON documents and compare them in a side-by-side highlighted diff.
JSON FormatterFormat, validate, and inspect JSON input as a readable tree in the browser.
JSON MinifierMinify and validate JSON input in the browser.
JSON to Crystal ClassInfer a Crystal JSON::Serializable class from JSON locally.
JSON to CSVConvert JSON into CSV locally.
JSON to HTMLConvert JSON into an HTML table locally.
JSON to IO-TSInfer an io-ts codec from JSON locally.
JSON to Pike ClassInfer a Pike class from JSON locally.
JSON to SarcasticConvert JSON into sarcastic TypeScript-like output.
JSON to SQLGenerate SQL INSERT statements from JSON locally.
JSON to SQL SchemaInfer a SQL table schema from JSON locally.
JSON to Swift StructInfer a Swift Codable struct from JSON locally.
JSON to TSVConvert JSON into TSV locally.
JSON to TypeScript InterfaceInfer a TypeScript interface from JSON locally.
JSON to YAMLConvert JSON into YAML locally.
Less to CSSCompile a small local subset of Less into CSS.
Markdown Table to HTML TableConvert Markdown tables into HTML tables locally.
SQL CompressorMinify SQL statements locally.
SQL FormatterFormat SQL statements locally.
SQL Schema to C# ClassGenerate a C# class from SQL schema locally.
SQL Schema to Python ClassGenerate a Python dataclass from SQL schema locally.
SQL Schema to TypeScript InterfaceGenerate a TypeScript interface from SQL schema locally.
SQL UnescapeUnescape SQL string literals locally.
YAML Formatter / CompressorFormat or compact YAML locally.
YAML to JSONConvert YAML into formatted JSON locally.

Encoding

Encode, decode, escape, and inspect common text and binary-safe formats.

Base64 CodecEncode and decode Base64 strings with UTF-8 support.
Base64 File DecodeDecode Base64 into a downloadable file locally.
Base64 File EncodeEncode a local file to Base64 without uploading it.
Base64 to HexConvert Base64 text into hexadecimal bytes locally.
CIDR CalculatorCalculate CIDR network details locally.
JSON Escape / UnEscapeEscape and unescape JSON string content locally.
JWT DecoderDecode, inspect, and verify JWTs locally.
Morse DecodeDecode Morse code into text locally.
Morse EncodeEncode text into Morse code locally.
Port Cheat SheetReference common network ports locally.
String EscapeEscape and unescape string literals locally.
URL CodecEncode and decode URL components or full URI strings.
URL ParseParse URL parts and query parameters locally.
UTF Encoding InspectorInspect UTF-8 and UTF-16 hex encodings locally.
UTF16 DecodeDecode UTF-16LE hex bytes locally.
UTF7 EncodeEncode and decode UTF-7 or IMAP UTF-7 locally.
UTF8 DecodeDecode UTF-8 hex bytes locally.
WebSocket TesterConnect to a WebSocket endpoint locally from the browser.

Crypto

Generate hashes, keys, signatures, and other browser-side cryptographic helper output.

AES DecryptionDecrypt AES text locally.
AES EncryptionEncrypt text with AES locally.
BCrypt VerifyVerify a password against a bcrypt hash.
CRC1 HashGenerate a CRC1 checksum locally.
CRC16-CCITT HashGenerate a CRC16-CCITT checksum locally.
CRC24 HashGenerate a CRC24 checksum locally.
CRC32 HashGenerate a CRC32 checksum locally.
DES DecryptionDecrypt DES text locally.
DES EncryptionEncrypt text with DES locally.
Hash GeneratorGenerate SHA digests for text input using the browser crypto API.
Htpasswd GeneratorGenerate htpasswd entries locally.
JWT EncoderGenerate and sign JWTs locally.
Keccak224 HashGenerate a Keccak224 hash locally.
PGP DecryptDecrypt PGP armored text locally.
PGP EncryptEncrypt text with a PGP public key locally.
PGP Key Pair GeneratorGenerate PGP key pairs locally.
PGP SignCreate a cleartext PGP signature locally.
PGP VerifyVerify a cleartext PGP signature locally.
Rabbit DecryptionDecrypt text with Rabbit locally.
Rabbit EncryptionEncrypt text with Rabbit locally.
RC4 DecryptionDecrypt RC4 text locally.
RC4 EncryptionEncrypt text with RC4 locally.
RSA DecryptionDecrypt RSA ciphertext locally.
RSA EncryptionEncrypt text with an RSA public key locally.
RSA Key Pair GeneratorGenerate RSA key pairs locally.
RSA Private to PublicExtract a public RSA key from a private key locally.
SHA3-512 HashGenerate a SHA3-512 hash locally.
SM2 DecryptionDecrypt SM2 ciphertext locally.
SM2 EncryptionEncrypt text with SM2 locally.
SM4 DecryptionDecrypt SM4 ciphertext locally.
SM4 EncryptionEncrypt text with SM4 locally.
Triple DES DecryptionDecrypt Triple DES text locally.
Triple DES EncryptionEncrypt text with Triple DES locally.

Time

Parse, convert, and inspect timestamps, dates, countdowns, and schedule expressions.

CountdownCount down to a target time locally.
CrontabDescribe five-field cron expressions locally.
Timestamp ConverterConvert timestamps or date strings into readable date values.

Text

Process plain text, QR content, image text, and document-friendly content formats.

Arabic to RomanConvert Arabic numerals into Roman numerals locally.
Barcode GeneratorGenerate a barcode image locally.
Barcode ScannerScan a barcode from an image or camera.
Chinese to PinyinConvert Chinese text to pinyin locally.
English PluralizePluralize English words locally.
Mermaid EditorEdit and preview Mermaid diagrams locally.
QR Code for EmailGenerate a QR code for email content.
QR Code for Ethereum AddressGenerate a QR code for an Ethereum address.
QR Code for Phone NumberGenerate a QR code for a phone number.
QR Code for SMSGenerate a QR code for an SMS payload.
QR Code for TextGenerate a QR code from plain text.
QR Code for URLGenerate a QR code from a URL.
QR Code ScannerScan a QR code from an image or camera.
Simplified to Traditional ChineseConvert between simplified and traditional Chinese locally.
Text Case ConverterConvert text into camelCase, snake_case, kebab-case, title case, or constant case.
Text ProcessorClean, filter, deduplicate, sort, and change case for line-based text locally.

Generator

Generate identifiers, styles, configuration, and other everyday developer assets.

Chmod CalculatorConvert between chmod octal and symbolic modes locally.
Color PickerPick and convert colors locally.
CSS Grid GeneratorGenerate CSS Grid snippets locally.
Loan CalculatorCalculate loan payment and interest locally.
LotteryRandomly pick items from a list locally.
Regex TesterTest regular expressions locally.
UUID / ULID GeneratorGenerate UUID v4 and ULID values locally.
UUID GeneratorGenerate RFC 4122 version 4 UUID values locally.
UUID ParserParse UUID version and variant information locally.