#214
B+
Rank #49
Stalwart
Modern all-in-one mail server (SMTP, IMAP, JMAP) written in Rust as a single binary. Standout trait is consolidating what usually takes 5+ services (Postfix/Dovecot/Rspamd/etc.) into one memory-safe binary.
76.5
/ 100
⚙ Full Stack
Single Rust binary implementing SMTP/IMAP/JMAP protocols with pluggable storage backends (RocksDB, FoundationDB, Postgres, or S3-compatible blob storage). No external process dependencies required for a functioning mail server.
📈 Scaling Analysis
The single-binary design with pluggable storage backends (including distributed FoundationDB) gives a genuinely credible scale-up and scale-out story unusual for mail servers. Still bound by the same external realities as any mail server — DNS reputation and IP warm-up — rather than internal architecture limits.
🚀 Running on Nexlayer
Deploy as a single stalwart pod with a persistent volume (or point it at an external Postgres/S3 backend via <podName>.pod:<port>); base the image on mirror.gcr.io if using a Debian/Alpine builder stage. Like Mailu, mail delivery still needs externally routable DNS/MX records regardless of how clean the in-cluster deployment is.