smtp-relay

An email and SMTP testing tool with API for developers

Simple Golang SMTP relay/proxy server

The first Open-Source high-performance MTA developed from the ground-up for high-volume email sending environments.

The collaborative Open Source successor to qmail and netqmail

Email inbox API for AI agents. Give every agent its own real email address, receive mail as structured webhooks, and reply in-thread over REST. A complete multi-tenant mail server in Rust: inbound and outbound, DKIM/SPF/DMARC/ARC, MTA-STS, DANE, three-tier anti-spam.

Self-hosted email gateway between your apps and a transactional mail provider (Postmark, Resend, Mailgun, AWS SES, or outbound-SMTP). Three ingress shapes (HTTP form, HTTP API, SMTP). One Docker container, one TOML config.

SimpleRelay - Self-hosted SMTP relay with web dashboard, DNS validation, and per-sender access control (FastAPI/Postfix/Docker)

Lightweight SMTP relay Docker image using msmtpd

Simple mail relay that can take unauthenticated SMTP emails (e.g. over port 25) and relay them to authenticated, TLS-enabled SMTP servers.

Docker image running a SMTP relay with postfix

SpamPD - Spam Proxy Daemon. A spam-filtering SMTP/LMTP proxy server using SpamAssassin in Perl. Since 2002.

Postfix Docker Image with great flexibility

SMTP server and SMTP relay host

SMTP Open Relay Exploitation

Keep scan-to-email working after Microsoft 365 retires SMTP Basic auth: SMTP to Microsoft Graph (OAuth) relay, least-privilege, never an open relay

SMTP Relay service for Windows

AWS-hosted personal email system: sending, receiving, storage, and forwarding (relaying). `notmuch` client. JMAP server WIP.

SMTP server to use for forwarding messages

Lightweight self-hosted mail server with SMTP/IMAP, catch-all mailboxes, multi-domain hosting, Web admin, DKIM/TLS, DNS diagnostics, Cloudflare DDNS, and SMTP relay.