email

Billionmail/BillionMail

Self-hosted mail server and newsletter platform in one stack — BillionMail bundles Postfix, Dovecot and Rspamd with a newsletter/email-marketing layer, letting you self-host transactional and campaign email without monthly SaaS fees. A one-command installer promises setup in minutes, aimed at businesses and developers wanting full control over sending, domains and analytics.

BillionMail gives you open-source MailServer, NewsLetter, Email Marketing — fully self-hosted, dev-friendly, and free from monthly fees. Join the discord: https://discord.gg/asfXzBUhZr

megadose/holehe

holehe allows you to check if the mail is used on different sites like twitter, instagram and will retrieve information on sites with the forgotten password function.

logto-io/logto

Open-source auth infrastructure built for AI agent platforms too — Logto handles OIDC, OAuth 2.1, and SAML with multi-tenancy, enterprise SSO, and RBAC out of the box, saving teams from wiring up these protocols themselves. It ships pre-built sign-in flows and SDKs for 30+ frameworks, and notably works out-of-the-box with Model Context Protocol and agent-based AI architectures, making it fit for both SaaS and emerging AI app stacks.

🧑‍🚀 Authentication and authorization infrastructure for SaaS and AI apps, built on OIDC and OAuth 2.1 with multi-tenancy, SSO, and RBAC.

elie222/inbox-zero

An open-source AI assistant that drafts, sorts and unsubscribes for you — Inbox Zero pairs an AI assistant with an email client for Gmail and Outlook: it pre-drafts replies in your tone, auto-blocks cold emails, bulk-unsubscribes, and files attachments. It's pitched as an open-source, more customizable and secure alternative to Fyxer, with Slack/Telegram control and meeting briefs.

The world's best AI personal assistant for email. Open source app to help you reach inbox zero fast.

reacherhq/check-if-email-exists

Verify email deliverability in Rust without sending a message — A Rust tool and HTTP backend that checks whether an email address is real without actually sending mail. Deployable via Docker, CLI, or API, it's aimed at developers wanting self-hosted email validation instead of a paid SaaS; a commercial version exists for those wanting a hosted UI.

Check if an email address exists without sending any email, written in Rust. Comes with a ⚙️ HTTP backend.

tutao/tutanota

Tuta is an email service with a strong focus on security and privacy that lets you encrypt emails, contacts and calendar entries on all your devices.

Mailu/Mailu

A self-hosted mail server stack that skips proprietary extras — Mailu packages a full email server—IMAP/SMTP, webmail, admin UI, DKIM/DMARC, Let's Encrypt, antispam—as Docker images for self-hosting. It adds modern touches like passkey sign-in, WKD key publication, and full-text attachment search, while deliberately avoiding bundled groupware or tracking, making it suited for privacy-minded admins who want control over their own mail infrastructure.

Insular email distribution - mail server as Docker images

macro-inc/macro

One workspace replacing Slack, Linear, Notion, HubSpot and Superhuman — Macro merges email, chat, docs, tasks, agents, calls and CRM into one SolidJS/Rust interface with shared team-level AI memory. Everything is @-linked and searchable, built by a team that dogfooded it for two years after scaling a startup to 20 people across disconnected tools.

Macro is a unified workspace for teams: email, chat, docs, tasks, agents, calls, and CRM — @-linked together with shared AI memory.

hieunc229/mailflare

Self-hosted email inbox built on Cloudflare, Resend, or SES — Mailflare lets you run your own email service for custom domains, using Cloudflare, Resend, or AWS SES as backends. Beyond basic mail, it bundles shared mailboxes, calendar scheduling with booking pages, routing rules, and an AI assistant with MCP access—aimed at teams and professionals wanting control over their own email stack.

Email for professionals and teams

marclou/mailcheap

Newsletters where you pay for the emails you send, not for dormant subscribers, at a fraction of the price of beehiiv and the like. Open source: self-host it, or use mailcheap.ai.

inlark/inlark

📧✨ Beautiful email. For everyone.

peterretief/yggstore

Pool machines over Yggdrasil for files, mail and sites — A Go toolkit letting people and organisations pool their own boxes over the Yggdrasil mesh, storing encrypted, erasure-coded files, email, websites and messaging without a central server or provider. It adds an S3 gateway for those without hardware and keeps full file history. Status: experimental, crypto unreviewed.

Files, email and websites kept on machines owned by the people and organisations using them, linked over Yggdrasil. Each file is encrypted and spread over several machines, and sites stay up when one is off. No central server. Open source.