Does SparkPost Send Emails as Encrypted Messages?
SparkPost supports Transport Layer Security (TLS). TLS and its predecessor, Secure Sockets Layer (SSL), are cryptographic protocols that provide security on the Internet and let you encrypt emails. All incoming API calls use HTTPS and are SSL/TLS encrypted. Incoming SMTP offers TLS, if the user choses to enable Encryption: STARTTLS. We also do opportunistic TLS for outbound traffic, which will depend on whether the receiving SMTP servers supports TLS.