What are some alternatives?
When comparing Tcl and Proofpoint, you can also consider the following products
Python - Python is a clear and powerful object-oriented programming language, comparable to Perl, Ruby, Scheme, or Java.
Virtru - Virtru is your data privacy force field, wrapping and protecting emails and files wherever they're shared. Easy-to-use data security software for business. People also askIs Virtru Hipaa compliant?
Assembly - Powered by intelligent technology, we’re delivering the content readers need, exactly when they need it, across four dynamic brands (and counting).
dmarcian - Safeguard your email from abuse
REBOL - Rebol (historically REBOL) is a cross-platform data exchange language and a multi-paradigm dynamic...
Cisco Email Security - Cisco Email Security protects against ransomware, business email compromise, spoofing, and phishing.