Open Source Email Tools
Email remains a core way to communicate, send account notifications, and reach audiences. The technology spans inboxes, mail servers, delivery protocols, and campaign systems. Open source email tools can help people manage messages, run their own infrastructure, send transactional mail, and reduce reliance on proprietary services. They also address practical needs such as deliverability, spam prevention, encryption, and control over stored data.
The category includes email clients, self-hosted mail servers, sending APIs, newsletter platforms, command-line tools, and services for routing or monitoring messages. When choosing a tool, consider its maturity, license, maintenance activity, deployment requirements, and compatibility with existing providers and standards such as SMTP. Security practices, privacy features, and expected delivery volume also matter. These tools are useful to individuals, developers, organizations, and operators who want more control over email workflows or infrastructure.
23 repositories · updated October 6, 2026
e2a: Email API for Applications and AI Agents
e2a provides an email API and relay for applications and AI agents. It supports transactional sending, inbound mailboxes, and agent replies, with optional human review and hosted or Docker-based deployment.
relay: Send Email Through Your Own Infrastructure
Hyvor Relay is a self-hosted email API that sends mail through your own SMTP infrastructure. It suits teams that want control over delivery operations, logs, and tenant or project separation rather than relying on a hosted sending provider.
osTicket: Manage Customer Support Tickets
osTicket is a self-hosted support ticket system that brings customer inquiries from email, phone, and web forms into one agent interface. It suits teams that need a web-based, open-source workflow for organizing and responding to support requests.
Zero: A Self-Hosted AI Email App
Zero is an open-source email app for managing accounts from providers such as Gmail and Outlook, with AI features and a focus on privacy. It suits people who want a customizable inbox they can self-host.
novu: Send Product and Agent Communications Across Channels
Novu provides a unified API and conversation model for product notifications and agent messaging. Use it to coordinate delivery across channels such as email, SMS, push, chat, and in-app inboxes without integrating each channel independently.
postcard: Create a Personal Website and Newsletter
Postcard is a self-hostable Rails app for publishing a personal website, blog posts, and an integrated newsletter. It suits people who want an owned online presence and mailing list instead of relying on social media.
00: Self-Host an AWS SES Email Dashboard
00 is a self-hosted dashboard and API for sending email through AWS SES and tracking delivery events. It connects SES notifications through SNS and SQS so developers can search messages and monitor recipient-level status in one place.
disposable-email-validator: Validate Emails Against Signup Rules
A TypeScript library for blocking disposable email domains and optionally plus-addressed emails. It lets applications apply different validation rules by environment, with allowlists and a built-in disposable-domain list.
aliasvault: Manage Passwords and Email Aliases Privately
AliasVault combines an encrypted password manager with disposable email aliases and a built-in email server. It suits people who want cross-platform access and the option to self-host their credentials and alias service.
OpenArchiver: Archive and Search Email for Compliance
OpenArchiver is a self-hosted platform for importing, preserving, and searching email from major providers and common archive formats. It suits organizations that need searchable records and retention controls, with deployment and storage managed on their own infrastructure.
forwardemail.net: Operate a Privacy-Focused Email Service
Forward Email is an email service codebase for domain-based forwarding and hosted mail, with web, SMTP, IMAP, POP3, CalDAV, and CardDAV services. It suits teams seeking to run or develop a privacy-focused email platform.
keila: Create and Send Newsletter Campaigns
Keila is a newsletter platform for creating campaigns and sign-up forms, with options to send through an existing inbox or supported email delivery services. It suits teams that want a hosted service or the option to run their own instance.