Open-source email software
237 open-source libraries, tools and applications tagged email, ranked by how closely email is their primary purpose, then by adoption and maintenance health. Each entry links to a page with sources, use cases and when to choose or avoid it.
237 products, primary matches first, then adoption-weighted; health v2 shown.
| Product | Health v2 | Stars | Maturity |
|---|---|---|---|
| adam-p/markdown-here Markdown Here is a browser and email-client extension (Chrome, Firefox, Opera, Safari, Thunderbird, Postbox) that lets users write email in… | 48 | 60265 | active |
| PHPMailer/PHPMailer PHPMailer is a full-featured PHP library for creating and sending email, with integrated SMTP support, authentication, attachments, HTML/mu… | 86 | 22296 | stable |
| Resend Email Platform React Email is a collection of high-quality, unstyled React components for building responsive email templates with TypeScript, handling em… | 93 | 19781 | active |
| docker-mailserver Docker Mailserver is a production‑ready, full‑stack mail server packaged as a Docker container. It bundles SMTP, IMAP, LDAP authentication,… | 97 | 19434 | active |
| docker-mailserver A production-ready, containerized fullstack mail server bundling Postfix (SMTP), Dovecot (IMAP/POP3), Rspamd, SpamAssassin, ClamAV, Fail2ba… | 97 | 19434 | active |
| mjmlio/mjml MJML is a markup language and open-source engine that compiles semantic, component-based markup into responsive HTML email that renders rel… | 95 | 18244 | stable |
| Mailspring Mailspring is a fully open source desktop email client for Mac, Windows, and Linux, built with Electron, React, and TypeScript, with a C++ … | 99 | 17908 | active |
| nodemailer/nodemailer Nodemailer is the most popular email sending library for Node.js, supporting SMTP, Sendmail, Amazon SES, and custom transports. It handles … | 99 | 17679 | stable |
| Billionmail/BillionMail BillionMail is a self-hosted, open-source mail server and email marketing platform built on Postfix, Dovecot, and Rspamd, with campaign man… | 63 | 15862 | active |
| Mail-in-a-Box Mail-in-a-Box is a one-click, easy-to-deploy mail server appliance that turns a fresh Ubuntu 22.04 machine into a complete email provider w… | 93 | 15443 | active |
| Stalwart Mail & Collaboration Server Stalwart is an open-source, all-in-one mail and collaboration server written in Rust, supporting JMAP, IMAP4, POP3, SMTP, CalDAV, CardDAV a… | 96 | 14870 | active |
| maillab/cloud-mail Cloud Mail is a self-hosted email service built on Cloudflare Workers that lets you create and manage multiple mailboxes using just a domai… | 85 | 14862 | active |
| thunderbird/thunderbird-android Thunderbird for Android is a free, open-source, privacy-focused email client for Android, formerly known as K-9 Mail and now part of the Mo… | 97 | 14050 | active |
| mailcow mailcow: dockerized is a full-featured, self-hosted mail server suite delivered as a set of Docker containers, bundling Postfix, Dovecot, S… | 99 | 13632 | stable |
| elie222/inbox-zero Inbox Zero is an open-source AI email assistant web application that organizes your inbox, pre-drafts replies in your voice, blocks cold em… | 97 | 12645 | active |
| dreamhunter2333/cloudflare_temp_email A self-hosted temporary/disposable email service built entirely on Cloudflare's free tier (Workers, Pages, Email Routing). It provides a mo… | 94 | 11944 | active |
| egulias/EmailValidator A PHP library for validating email addresses against multiple RFC standards (5321, 5322, 6530-6532, 1035). It offers pluggable validation s… | 32 | 11639 | stable |
| Mail-0/Zero Zero (Mail0) is an open-source, self-hostable email client that unifies multiple providers like Gmail and Outlook into one privacy-first in… | 46 | 10857 | active |
| axllent/mailpit Mailpit is a lightweight, zero-dependency email and SMTP testing tool for developers that acts as a local SMTP server and captures outgoing… | 95 | 10590 | active |
| Reacher Email Verification A Rust library and CLI that checks whether an email address exists via SMTP/MX lookups without sending an actual email. It also ships as a … | 85 | 10093 | active |
| openclaw/gogcli gog is a single Go binary CLI that provides terminal access to Google Workspace services including Gmail, Calendar, Drive, Docs, Sheets, Sl… | 80 | 8512 | active |
| cloudflare/agentic-inbox A self-hosted email client with an integrated AI agent that runs entirely on Cloudflare Workers. Incoming mail is handled via Cloudflare Em… | 46 | 8237 | active |
| tutao/tutanota Tuta Mail (formerly Tutanota) is an open-source, end-to-end encrypted email service with integrated encrypted calendar and contacts, availa… | 93 | 7967 | active |
| Mailu Mailu is a full-featured, self-hosted email server distributed as a set of Docker images, providing SMTP, IMAP, webmail, and an admin inter… | 100 | 7567 | active |
| Himalaya Himalaya is a command-line email client written in Rust for listing, reading, composing, sending, searching, and moving messages. It suppor… | 85 | 7318 | active |
| Roundcube Webmail Roundcube Webmail is a browser-based, multilingual IMAP email client written in PHP with an application-like user interface. It offers full… | 94 | 7192 | stable |
| SimpleLogin SimpleLogin is an open-source email aliasing service that lets users create unique aliases to receive and send emails without exposing thei… | 93 | 7012 | active |
| jstedfast/MailKit MailKit is a cross-platform .NET mail client library built on top of MimeKit, providing IMAP, POP3, and SMTP support along with a high-perf… | 77 | 6863 | stable |
| sj26/mailcatcher MailCatcher is a Ruby gem that runs a lightweight fake SMTP server which catches all outgoing mail from an application and displays it in a… | 66 | 6780 | stable |
| maildev/maildev MailDev is a local SMTP server with a modern web interface that catches all emails sent by your application during development, so nothing … | 93 | 6145 | active |
| foxcpp/maddy Maddy is a composable all-in-one mail server written in Go that combines an SMTP MTA/MX, IMAP storage, and email security protocols (DKIM, … | 98 | 6107 | active |
| openpgpjs/openpgpjs OpenPGP.js is a pure JavaScript implementation of the OpenPGP protocol (RFC 9580), maintained by Proton Mail. It lets applications encrypt,… | 87 | 5966 | stable |
| mjl-/mox Mox is an all-in-one, secure, open source mail server written in Go, combining SMTP, IMAP4, webmail, SPF/DKIM/DMARC, DANE/MTA-STS, automati… | 89 | 5864 | active |
| tijsverkoyen/CssToInlineStyles A PHP library that converts HTML pages or files by inlining their CSS styles directly into the HTML elements. This is primarily useful for … | 51 | 5823 | stable |
| Mailtrain-org/mailtrain Mailtrain is a self-hosted newsletter application built on Node.js and MySQL/MariaDB for managing subscriber lists and sending email campai… | 39 | 5759 | active |
| Proton Mail Suite The official monorepo for Proton's web clients, including Proton Mail, Calendar, Drive, VPN, Pass, Wallet, and more. It is built with React… | 82 | 5644 | active |
| haraka/Haraka Haraka is a fast, highly extensible, event-driven SMTP server written in Node.js with a modular plugin architecture. It is widely deployed … | 93 | 5618 | stable |
| useplunk/plunk Plunk is an open-source, self-hostable email platform combining transactional email sending (API and SMTP), marketing campaigns, and event-… | 89 | 5499 | active |
| Unlayer Email Editor An official React component that embeds Unlayer's drag-and-drop email editor into any React application. It lets developers load and save e… | 91 | 5232 | active |
| addy.io The self-hostable source code for addy.io (formerly AnonAddy), an open-source anonymous email forwarding service. It lets users create emai… | 98 | 4885 | active |
| M66B/FairEmail FairEmail is a fully featured, open source, privacy oriented email client for Android. It supports unlimited accounts via standard protocol… | 95 | 4714 | active |
| usesend/useSend useSend is an open-source, self-hostable email sending platform built on Amazon SES, offering transactional and marketing email delivery wi… | 84 | 4700 | active |
| sdushantha/tmpmail tmpmail is a command line utility written in POSIX sh that creates temporary/disposable email addresses and receives emails via the 1secmai… | 23 | 4185 | stable |
| imapsync/imapsync Imapsync is a command-line tool written in Perl that performs incremental, recursive, duplicate-free transfers between two IMAP mailboxes. … | 75 | 4180 | active |
| rnwood/smtp4dev smtp4dev is a fake SMTP email server for development and testing, with a web interface, terminal UI, and REST API. It captures outgoing mai… | 86 | 3981 | active |
| arikchakma/maily.to Maily is a powerful, opinionated WYSIWYG email editor built on Tiptap and React, offering pre-designed, mobile-ready components for craftin… | 73 | 3976 | active |
| gmail.js Gmail.js is a JavaScript library that provides an unofficial API for interacting with Gmail's web interface from browser extensions. It let… | 77 | 3848 | active |
| neomutt/neomutt NeoMutt is a highly configurable, terminal-based command line email reader (MUA) forked from Mutt, written in C. It consolidates many commu… | 87 | 3838 | active |
| ryanb/letter_opener A Ruby gem that intercepts outgoing email in development and previews it in the browser instead of sending it. It integrates with Rails Act… | 64 | 3838 | stable |
| MailHog MailHog is an email testing tool that runs a fake SMTP server and exposes a web UI and JSON API for inspecting outgoing messages. It can op… | 23 | 16189 | maintenance |
| forwardemail/email-templates A Node.js library for creating, previewing, and sending custom email templates with automatic CSS inlining. It integrates with Nodemailer a… | 72 | 3739 | active |
| mikel/mail Mail is a pure Ruby library for generating, parsing, and sending/receiving email messages in a simple, Ruby-esque way. It proxies network a… | 75 | 3670 | stable |
| sofn-xyz/mailing Mailing is an open-source TypeScript tool for building, testing, and sending emails using React components and MJML. It includes a hot-relo… | 70 | 3606 | active |
| Modoboa Modoboa is an open-source mail hosting and management platform with a modern web UI, built in Python/Django and Vue. It integrates Postfix,… | 96 | 3537 | stable |
| ChangemakerStudios/Papercut-SMTP Papercut SMTP is a desktop application that runs a local SMTP server and displays every email your application sends, so nothing is ever de… | 91 | 3339 | active |
| Automattic/juice Juice is a JavaScript library and CLI that inlines CSS stylesheets into HTML by converting CSS rules into style attributes. It is primarily… | 98 | 3284 | active |
| dafthack/MailSniper MailSniper is a PowerShell-based penetration testing tool for searching email in Microsoft Exchange environments for sensitive terms like p… | 75 | 3281 | active |
| zalify/easy-email-editor Easy Email Editor is an open-source React component library for building drag-and-drop email editors that generate responsive HTML via MJML… | 72 | 3246 | active |
| lukencode/FluentEmail FluentEmail is an all-in-one email sending library for .NET and .NET Core with a fluent API. It supports multiple senders (SMTP, SendGrid, … | 32 | 3215 | stable |
| GAM-team/got-your-back Got Your Back (GYB) is a Python command line tool that backs up and restores Gmail messages to your local computer using Gmail's API over H… | 98 | 3134 | active |
| leafac/kill-the-newsletter A self-hostable web application that converts email newsletters into Atom feeds. It gives each feed a unique email address; incoming newsle… | 98 | 3114 | active |
| matcornic/hermes Hermes is a Go package that generates clean, responsive HTML emails for transactional mail such as welcome, password-reset, and receipt ema… | 26 | 3029 | active |
| dittofeed/dittofeed Dittofeed is an open-source, omni-channel customer engagement platform for sending transactional and marketing messages via email, SMS, mob… | 82 | 3002 | active |
| charmbracelet/pop Pop is a terminal-based tool for sending emails, offering both an interactive TUI and a CLI for piping Markdown messages with attachments. … | 93 | 2923 | active |
| symfony/mime Symfony MIME is a PHP component for creating and manipulating MIME messages, including email construction with headers, attachments, and mu… | 92 | 2829 | stable |
| beilunyang/moemail MoeMail is a self-hostable temporary (disposable) email service with a cute web UI, built on Next.js and the Cloudflare stack (Pages, Worke… | 80 | 2822 | active |
| kootenpv/yagmail yagmail is a Python library that makes sending emails via Gmail/SMTP as simple as a single client call, with 'magical' handling of text, HT… | 66 | 2738 | active |
| LukeSmithxyz/mutt-wizard mutt-wizard is a shell-based tool that automatically configures the neomutt terminal email client along with isync and msmtp, including IMA… | 62 | 2649 | active |
| eladnava/mailgen A Node.js package that programmatically generates clean, responsive HTML emails for transactional mail, with bundled themes and plaintext o… | 77 | 2540 | stable |
| rspamd/rspamd Rspamd is an advanced spam filtering system and email processing framework written in C with an extensive Lua plugin API. It evaluates mess… | 96 | 2534 | active |
| LogicLabs-OU/OpenArchiver OpenArchiver is an open-source, self-hosted platform for legally compliant email archiving and eDiscovery. It ingests email from Google Wor… | 87 | 2422 | active |
| premailer/premailer Premailer is a Ruby gem that prepares HTML email for delivery by inlining CSS styles, converting relative URLs to absolute, and checking CS… | 75 | 2416 | active |
| emersion/go-imap go-imap is an IMAP4rev2 protocol library for Go, providing both client and server implementations. It lets Go applications talk to mail ser… | 76 | 2356 | active |
| Jinnrry/PMail PMail is a lightweight personal email server written in Go that ships as a single ~15MB binary with full send/receive SMTP/POP3 services an… | 88 | 2321 | active |
| inbucket/inbucket Inbucket is a self-hosted disposable webmail (email testing) server that accepts messages for any address via built-in SMTP and exposes the… | 88 | 2309 | stable |
| SendWithSES/Drag-and-Drop-Email-Designer An open-source Angular library providing a drag-and-drop HTML email template designer with no-code editing, HTML code editing, and plain te… | 62 | 2307 | active |
| lettre/lettre lettre is a mailer library for Rust that lets applications compose and send emails via SMTP, sendmail, and other transports. It offers a st… | 91 | 2272 | stable |
| mailpile/Mailpile Mailpile is a free, open-source, privacy-focused email client with built-in PGP encryption, a fast custom search engine, and tag-based orga… | 23 | 8811 | maintenance |
| postalsys/emailengine EmailEngine is a self-hosted, source-available (not open-source) headless email client that exposes IMAP, SMTP, Gmail API, and Microsoft Gr… | 92 | 2228 | active |
| pentacent/keila Keila is an open source (AGPL-3.0) email newsletter tool written in Elixir, positioned as an alternative to Mailchimp or Sendinblue. It sup… | 96 | 2223 | active |
| Notifuse/notifuse Notifuse is an open-source, self-hosted email marketing and transactional email platform built with Go and React. It offers a visual MJML d… | 80 | 2216 | active |
| eleith/emailjs emailjs is a TypeScript library for sending text and HTML emails with attachments (files, streams, or strings) to any SMTP server from Node… | 73 | 2209 | active |
| langchain-ai/executive-ai-assistant Executive AI Assistant (EAIA) is an open-source AI agent built with LangGraph that performs the job of an executive assistant, primarily by… | 10 | 2207 | active |
| mbrt/gmailctl gmailctl is a Go CLI tool that lets you manage Gmail filters declaratively using Jsonnet configuration files. It applies filters directly t… | 78 | 2198 | active |
| SendPortal SendPortal is an open-source, self-hosted email marketing application for managing newsletters, subscribers, and campaigns. It is a Laravel… | 23 | 2174 | active |
| SOGo SOGo is an open-source groupware (collaboration) server offering webmail, shared calendars, address books, and tasks. It uses open standard… | 93 | 2171 | stable |
| LukeSmithxyz/emailwiz A shell script that automates installing and configuring a full email server on Debian/Ubuntu using Postfix, Dovecot, Spamassassin, OpenDKI… | 77 | 2170 | active |
| Gururagavendra/gmail-cleaner A free, open-source, self-hosted web application for bulk cleaning of Gmail inboxes. It runs locally via Docker or Python and uses the Gmai… | 64 | 2119 | active |
| s1t5/mail-archiver Mail-Archiver is a self-hosted web application for archiving, searching, and exporting emails from multiple accounts (IMAP, Microsoft 365, … | 84 | 2118 | active |
| zone-eu/wildduck WildDuck is a scalable, no-single-point-of-failure IMAP/POP3 email server built on Node.js that stores all mail in sharded and replicated M… | 98 | 2109 | active |
| Qoraiche/laravel-mail-editor MailEclipse is a Laravel package that provides a web UI for creating, editing, and previewing mailables without using the command line. It … | 33 | 2108 | active |
| Mailcheck A JavaScript library and jQuery plugin that detects misspelled email domains and suggests corrections, e.g. turning '[email protected]' into 'u… | 84 | 7937 | maintenance |
| emersion/go-smtp An ESMTP client and server library for Go implementing RFC 5321 with extensions like AUTH, PIPELINING, and LMTP. It improves on the frozen … | 90 | 2052 | active |
| foundation/foundation-emails Foundation for Emails (formerly Ink) is an HTML/CSS framework for building responsive HTML emails that render consistently across email cli… | 72 | 7791 | maintenance |
| rustmailer/bichon Bichon is a self-hosted email archiving server written in Rust that downloads emails from IMAP accounts, builds a full-text search index, a… | 84 | 2021 | active |
| jstedfast/MimeKit MimeKit is a C#/.NET library for creating and parsing MIME email messages, with support for S/MIME, OpenPGP, DKIM, ARC, TNEF, and Unix mbox… | 77 | 2008 | stable |
| ZeroPointSix/outlookEmailPlus OutlookMail Plus is a self-hosted email manager purpose-built for account registration and verification workflows. It automates fetching ve… | 76 | 1996 | active |
| beam-community/bamboo Bamboo is an adapter-based email library for Elixir that separates email creation from delivery, with built-in adapters for services like M… | 66 | 1960 | stable |
| O365/python-o365 A Python library providing a Pythonic wrapper around the Microsoft Graph and Office 365 REST APIs. It supports email, calendar, contacts, O… | 65 | 1924 | active |
| FGRibreau/mailchecker MailChecker is a cross-language library for validating email format and detecting temporary/disposable email addresses, backed by a databas… | 77 | 1913 | active |
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