Tools below also have their own public APIs. Check them out, it's free and no registration needed!
MD5 Checker Online Tool
Free online dictionary attack on hashed MD5 string with huge database list. Check if I may have one of your need!Use This!
Online DNS Query
Fetch DNS Resource Records associated with a given hostname. Get DNS record for SOA, NS, A, AAAA, and MX.Use This!
Various Online String Generator
Primarily intended to help people in converting or calculating strings to different modes.Use This!
Online Email Validator Tool
Free online tool to verify an email addresses format and check its MX records from its authoritative DNS server.Use This!