#1
Postal is an open source mail delivery platform for sending and receiving email, with SMTP support, web-based management, and tools for running your own SendGrid-style service.
16.8k stars1.3k forksMITlast commit Actively maintained
11 self-hosted SocketLabs alternatives
Cloud email delivery platform for transactional and marketing messages. Provides SMTP and API sending, deliverability monitoring and analytics, suppression and compliance management, reporting and migration support for developers and businesses.
Alternatives to SocketLabs
#2
Haraka is a fast, event-driven SMTP server for receiving, filtering, and relaying email, featuring a modular plugin architecture for customization at scale.
5.6k stars712 forksMITlast commit Actively maintained
AGPL-3.0 open-source email API for developers that can be self-hosted; supports SMTP sending, webhooks, DNS automation, observability, multi-tenancy, and project isolation.
876 stars59 forksAGPL-3.0last commit Actively maintained
A small, C-based Mail Transfer Agent for local submission and outbound relay with TLS/SMTP authentication, aimed at home and small office use.
263 stars59 forkslast commit Likely dormant
#5
Exim is an open source SMTP message transfer agent (MTA) for Unix-like systems, offering flexible mail routing and extensive controls for handling inbound email.
Activity unknown
#6
Lightweight SMTP server written in Go that receives and sends email via a single JSON config and executable hooks; supports per-user DKIM and TLS.
Activity unknown
E-MailRelay is a lightweight SMTP relay/store-and-forward mail server with optional POP3 access to spooled messages, designed for simple, scriptable mail handling.
Activity unknown
OpenSMTPD is an open-source, minimal SMTP daemon from the OpenBSD project providing an RFC-compliant MTA with privilege separation, table backends, filters and TLS support.
Activity unknown
#9
Postfix is a fast, secure, and easy-to-administer SMTP server for sending and routing email on Unix-like systems, commonly used as an MTA or mail relay.
Activity unknown
Open Source Sendmail provides a subset of Proofpoint's Sendmail Sentrion MTA for large-scale mail deployments; current release is 8.16.1 with a PGP-signed tarball and OpenDKIM integration.
Activity unknown
#11
chasquid is a minimalist SMTP server (MTA) for individuals and small groups, focused on secure defaults, easy configuration, and straightforward operation.
Activity unknown
What replacing SocketLabs actually involves
Every option on this page is open source and free to run on your own hardware, so you own the data and there is no subscription to cancel. 3 of 11 shipped a commit in the last six months. Licences in this list: MIT, AGPL-3.0. In exchange you take on hosting, backups and updates yourself.
Browse everything in Email Servers (SMTP/IMAP).
