Email & Communication

Inbox Zero

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.

Zero

MIT

Self-hostable email client that connects to your existing accounts and gives you full control over your data, interface, and inbox experience.

Novu

Unknown

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

Freescout

AGPL-3.0

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

Keila

AGPL-3.0

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

Plunk

AGPL-3.0

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

Postal

MIT

Self-hosted email delivery platform with powerful features for transactional and bulk emails, offering full control and customization.

Sendportal

MIT

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

useSend

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.

UnInbox

Unknown

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

Ntfy

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.

AgentMail

Unknown

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

DoubleZero

AGPL-3.0

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

Hyvor Relay

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.

Sessy

Unknown

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

Tuta

GPL-3.0

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

Twake Mail

AGPL-3.0

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