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Open Source Email & Communication Tools

A curated collection of the best open source tools related to email and other communication methods.

See also:Email ClientsSecure Email ProvidersEmail PlatformsPush Notification
Favicon of Novu

Novu

Multi-channel notification infrastructure for apps

  • Stars

    39,652

  • Last commit

    5 hours ago

  • License

    Unknown
Open-source platform for building in-app, email, push, SMS, and chat notifications with a unified API, workflow engine, and embeddable inbox component.

Open Source Alternative to:

Favicon of Customer.io
Customer.io
Favicon of Macro Mail

Macro Mail

Keyboard-first email client with AI, chat, and tasks

  • Stars

    4,000

  • Last commit

    7 hours ago

  • License

    AGPL-3.0
An AI-powered email client that combines inbox management, chat, tasks, and AI agents in one shared workspace, built for keyboard-driven workflows.

Open Source Alternative to:

Favicon of Gmail
Gmail
Favicon of Ntfy

Ntfy

Simple, fast, and secure push notifications for all

  • Stars

    33,713

  • Last commit

    4 days ago

  • License

    Apache-2.0
A lightweight, open-source solution for sending real-time notifications to your devices, with end-to-end encryption and no sign-up required.

Open Source Alternative to:

Favicon of LogSnag
LogSnag
Favicon of Inbox Zero

Inbox Zero

AI email assistant that automates, organizes, and declutters

  • Stars

    12,069

  • Last commit

    12 hours ago

  • License

    AGPL-3.0
Automates Gmail and Outlook with AI-drafted replies, bulk unsubscribe, cold email blocking, attachment filing, and inbox analytics for individuals and teams.

Open Source Alternative to:

Favicon of Superhuman Mail
Superhuman Mail
Favicon of Tuta

Tuta

Secure email, calendar and contacts with end-to-end encryption

  • Stars

    7,871

  • Last commit

    3 days ago

  • License

    GPL-3.0
Tuta offers encrypted email, calendar and contacts with quantum-resistant security, protecting your privacy without ads or tracking.

Open Source Alternative to:

Favicon of Gmail
Gmail
Favicon of Plunk

Plunk

The open-source, affordable email platform

  • Stars

    5,386

  • Last commit

    16 hours ago

  • License

    AGPL-3.0
Plunk unifies marketing, transactional, and broadcast emails into a single, complete solution for businesses of all sizes.

Open Source Alternative to:

Favicon of Resend
Resend
Favicon of useSend

useSend

Pay per email sent, not for contact storage

  • Stars

    4,631

  • Last commit

    19 hours ago

  • License

    AGPL-3.0
Open source email platform for transactional and marketing emails. Self-host or use cloud service with transparent pricing - pay only for emails sent.

Open Source Alternative to:

Favicon of Resend
Resend
Favicon of Freescout

Freescout

Open-source helpdesk for seamless customer support

  • Stars

    4,498

  • Last commit

    5 hours ago

  • License

    AGPL-3.0
Self-hosted email management system with shared inboxes, automation, and powerful collaboration features for efficient customer support.

Open Source Alternative to:

Favicon of Zendesk
Zendesk
Favicon of Keila

Keila

Open-source email marketing for the privacy-conscious

  • Stars

    2,191

  • Last commit

    5 days ago

  • License

    AGPL-3.0
Self-hosted newsletter platform with powerful features, data protection, and full control over your mailing lists and campaigns.

Open Source Alternative to:

Favicon of Substack
Substack
Favicon of Sendportal

Sendportal

Self-hosted email marketing with unlimited everything

  • Stars

    2,159

  • Last commit

    2 years ago

  • License

    MIT
Open-source email marketing platform offering unlimited subscribers, campaigns, and workspaces. Self-hosted solution with powerful API and beautiful interface.

Open Source Alternative to:

Favicon of Resend
Resend
Favicon of UnInbox

UnInbox

Transform team email into efficient collaborative workflows

  • Stars

    1,755

  • Last commit

    6 months ago

  • License

    AGPL-3.0
Streamline team communication with shared inboxes, unlimited email addresses, and customizable workflows. Perfect for modern businesses seeking organized email management.

Open Source Alternative to:

Favicon of Gmail
Gmail
Favicon of Sessy

Sessy

Own your SES email analytics, from send to inbox

  • Stars

    914

  • Last commit

    5 days ago

  • License

    Unknown
Track SES deliveries, bounces, opens and clicks in a self-hosted dashboard with real-time search, analytics and reputation monitoring.

Open Source Alternative to:

Favicon of Resend
Resend
Favicon of Hyvor Relay

Hyvor Relay

Open-source email API with enterprise deliverability

  • Stars

    871

  • Last commit

    2 days ago

  • License

    AGPL-3.0
Self-hosted email API alternative to AWS SES & Mailgun. Open-source AGPL-3.0 with enterprise features, automated deliverability, and cloud version coming 2026.

Open Source Alternative to:

Favicon of Resend
Resend
Favicon of DoubleZero

DoubleZero

Self-hosted email infrastructure for developers

  • Stars

    1,249

  • Last commit

    2 years ago

  • License

    AGPL-3.0
00 is an open-source email API and infrastructure solution that allows developers to own and control their email stack.

Open Source Alternative to:

Favicon of Resend
Resend
Favicon of Twake Mail

Twake Mail

Secure open source email with advanced encryption & AI

  • Stars

    647

  • Last commit

    7 hours ago

  • License

    AGPL-3.0
Open source professional email solution with PGP encryption, JMAP protocol, AI-powered responses, and advanced antispam protection. Control your data privately.

Open Source Alternative to:

Favicon of Gmail
Gmail
Favicon of AgentMail

AgentMail

AI
Email inbox API built for AI agents and workflows

  • Stars

    38

  • Last commit

    5 days ago

  • License

    MIT
Provides AI agents with real email inboxes via REST API. Create inboxes instantly, send and receive messages, search threads, and handle attachments programmatically.
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