Add MailboxValidator

Business/MailboxValidator.md

@@ -0,0 +1,48 @@
+# [MailboxValidator](https://www.mailboxvalidator.com/api-email-free)
+
+## __Description__
+Validate email address to improve deliverability
+
+## __Example Request__
+* Curl
+```
+curl https://api.mailboxvalidator.com/v1/email/free?email=test@test.com&key={{token}}
+```
+
+* Raw
+```
+GET /v1/email/free?email=test@test.com&key={{token}} HTTP/1.1
+Host: api.mailboxvalidator.com
+```
+
+## __Response__
+* Success
+```
+{
+    "email_address":"test@test.com",
+    "is_free":"False",
+    "credits_available":999,
+    "error_code":"",
+    "error_message":""
+}
+```
+* Error
+```
+{
+    "email_address":"",
+    "is_free":"",
+    "credits_available":"",
+    "error_code":"101",
+    "error_message":"API key not found."
+}
+```
+
+## __Regex__
+```
+[A-Z0-9]{20}
+```
+
+## __Example API key__
+```
+1MA2C3BBBASAAAA6AA77
+```