On freeformatter.com/ you have many free online tools for developers. The tools contain converter, formatters, decryptors, validators and many more. It could be used for XML, HTML, SQL, JSON…
A guick list of the possibilities:
Formatters
- JSON Formatter
- HTML Formatter
- XML Formatter
- SQL Formatter
Validators
- JSON Validator
- HTML Validator
- XML Validator – XSD
- XSD Generator
- XPath Tester
- Credit Card Number Generator & Validator
- Regular Expression Tester
Encoders & Decoders
- Url Encoder & Decoder
- Base 64 Encoder & Decoder
- QR Code Generator
Code Minifiers
- JavaScript Minifier
- CSS Minifier
Converters
- XSLT (XSL Transformer)
- XML to JSON Converter
- JSON to XML Converter
- CSV to XML Converter
- Epoch Timestamp To Date
Cryptography
- Message Digester
- HMAC Generator
String Escaper & Utilities
- String Utilities
- HTML Escape
- XML Escape
- Java and .Net Escape
- JavaScript Escape
- CSV Escape
- SQL Escape
Web Resources
- Lorem Ipsum Generator
- LESS Compiler
- List of MIME types
- HTML Entities
- URL Parser / Query String Splitter
- ISO country list – HTML select snippet
- USA state list – HTML select snippet
- Canada province list – HTML select snippet
- Time zone list – HTML select snippet