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Self-hosted email server for 2026

single binary, CalDAV

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Built this after getting frustrated with the paying to a google for email. Now running it for 1 months in production.What it does: - Full SMTP server (inbound/outbound, DKIM signing, SPF/DMARC checking) - IMAP with IDLE support - CalDAV/CardDAV (replace Google Calendar/Contacts) - Web admin panel with Prometheus metrics - Greylisting for spam prevention - Auto-discovery (mail clients configure themselves) - Audit logging for complianceWhat it doesn't do: - Webmail (use Roundcube, etc.) - ML-based spam filtering (greylisting + basic heuristics only) - Clustering/HA

HN · launched Jan 3, 2026 · 7 upvotes (top 65%) · 1 view

Niche: self-hosted software platforms · 79 launches, 5 in the last 7 days ▼ -50% · Explore this niche →

Category and tags
  • Horizontal
  • Communication
  • Prosumer
  • Not AI
  • Hobby / open-source project

Visit website ↗ Source listing ↗

More like this: all 79 launches in self-hosted software platforms →

Could you build this?

No Writing a compliant, secure, single-binary email and CalDAV server implementing full SMTP, DKIM/SPF/DMARC, and IMAP IDLE requires deep protocol implementation and email deliverability expertise that vibe coding cannot safely replicate.

What it would actually take: The architecture requires a systems language (Go or Rust) implementing low-level RFCs for SMTP (RFC 5321), IMAP4rev1 (RFC 3501) with IDLE, MIME parsing, cryptographic signing (DKIM), and WebDAV/CalDAV/CardDAV specs (RFC 4791, 6352). Beyond protocol engineering, real-world deployment requires strict memory safety, robust queue persistence, TLS handling, spam filtering (Rspamd integration), and navigating IP warming and global deliverability blacklists.

Discussion

5 comments analyzed.

Competitors mentioned: Maddy, Mox, Stalwart, Google Workspace, Postgres/MySQL

Concerns raised: Unclear differentiation from established mail server alternatives, Server binds to all interfaces by default without configuration option

Feature requests: bind_address config option for multi-homed machines, API for transactional emails, Webhooks support

Competitors

Other products that read as similar to this one : 215 launches clear the similarity bar, closest 8 shown.

Attention rank: #100 of 216 (itself plus its competitors, highest first, normalized so YC and Product Hunt are compared fairly).

Launched 17 days after the earliest competitor.

Related data

The niche, labels, vibe code rating and competitor comparison on this page are analysis by Nicheloom. If you use them, please credit nicheloom.com. How you may use our data.