MX Guarddog vs Rspamd

MX Guarddog is a hosted email gateway for standard SMTP servers serving owned domains. It scans incoming messages for spam, phishing, malware and viruses, quarantines offending mail, and forwards clean messages to the customer’s server. The service runs in the cloud, so it requires no hardware or software installation and no configuration changes to email clients or the server. Quarantine reports summarize stopped spam, and users can adjust report preferences; quarantine retention is seven days. If a customer’s server is unavailable, MX Guarddog says it holds mail for up to 168 hours and delivers it when the server returns. It can sync active addresses from Windows AD, LDAP or cPanel, and says it uses Transport Layer Security, including Perfect Forward Security, for email in transit. The listed per-address price is $0.25 per month; aliases are not charged. A free plan and 30-day trial are listed. The service is for web use and does not support consumer Gmail or Hotmail accounts.

Rspamd is an email security engine for filtering phishing, business email compromise, malicious attachments, and spam. It scores messages using reputation, sender authentication, content analysis, and machine learning. Authentication checks cover SPF, DKIM, DMARC, and ARC; malware scanning can use ClamAV or commercial antivirus engines. Administrators can define custom rules through the Lua API and configurable maps and selectors. Rspamd works with mail transfer agents including Postfix, Exim, and Sendmail, and its ClickHouse and Elasticsearch integrations provide visibility into attack patterns and detection rates. It is designed for gateway deployment and can run on-premises, keeping message data in the operator's environment without a mandatory vendor cloud. The detection engine is open source under Apache 2.0 and is available for Linux, macOS, and self-hosted use. Rspamd says its event-driven C core scans hundreds of messages per second per core and can scale from a single server to billions of messages a day. The open-source engine is listed at free. Scale costs £100 a month, with 5K mailboxes; hosted and enterprise plans have custom pricing. Premium plans offer support from core engineers, with enterprise SLA options.