Best Open-Source Bulk Email Sender Tools (GitHub) to Use in 2025–2026

Why open-source bulk email tools make sense

The best free bulk email senders are usually open-source software you install yourself, not a rebranded SaaS free plan. That distinction matters: services like Mailchimp or Brevo let you send for free only up to a certain list size or monthly volume, then bill you once you cross it. Every tool in this guide is different. You run it on your own server, and the only ceiling on how much you can send is your own infrastructure and your email provider’s sending rules, not a pricing tier.

That trade-off comes with real advantages:

• You own the data. Subscriber lists, campaign history, and analytics stay on your server, not a vendor’s.
• No subscription bill. Once it’s installed, sending capacity is bounded by your hosting, not a plan you’re paying for.
• You can change how it works. The code is open, so you can extend or integrate it into an existing workflow instead of working around a closed API.
• It’s a better fit for privacy rules like GDPR, since subscriber data isn’t routed through a third party by default.

Below are five actively maintained open-source projects worth considering, checked and current as of September 2026, roughly in order of how much sending volume they’re built for: from established, high-volume systems down to small, single-purpose senders.

Top open-source bulk email senders

phpList

phpList is one of the oldest tools in this space, now on version 3. It has 870 GitHub stars, 289 forks, and just under 4,000 commits, and it’s licensed under AGPLv3. phpList has long advertised translation into around 20 languages, though its current Weblate localization project shows broader coverage today (roughly 54). phpList’s own materials cite a figure of more than 25 billion campaign emails sent across 95 countries, but that number is dated to 2018 in the same materials, not a current count, so treat it as a sign of long-term scale rather than an up-to-date usage statistic.

The feature set covers a web UI plus a command-line interface, load balancing and throttling across campaigns, scheduled sends, CSV/Excel import and export, custom HTML templates, attachments, and bounce processing. If you’d rather not self-host, phpList also sells a hosted version at phplist.com.

Best for: organizations that want a proven, actively maintained tool for recurring newsletters rather than a newer, less-tested project.

BillionMail

BillionMail is newer and considerably more active right now: 15,600+ GitHub stars, 1,700+ forks, and over 1,300 commits on its dev branch. It’s a full mail server (Postfix and Dovecot underneath) bundled with a campaign-management layer, webmail through RoundCube, and spam filtering via rspamd, all under AGPLv3, with a Docker Compose install the project says takes about eight minutes.

One thing worth correcting here: the name implies unlimited sending, but there’s no such thing as unlimited email delivery in practice. Actual throughput is set by your server, your SMTP relay’s rate limits, and your sender reputation, not by the software. What BillionMail actually gives you is a mail server plus a marketing layer with no artificial send cap built in, which is a narrower claim than “send a billion emails.”

Best for: teams that want the mail server and the marketing tool in a single self-hosted stack, and are comfortable managing DNS, DKIM/SPF, and IP reputation themselves.

Bulk-Email-Sender (Laravel)

This is a Laravel application built specifically for bulk sending: contact management with tags, CSV/Excel import and export, multi-SMTP account support, scheduled sends, real-time delivery-status tracking, and background queue processing so large sends don’t block the UI. It runs on Laravel 10 and PHP 8.1+, with a MySQL or PostgreSQL backend, and ships under the MIT license, which means fewer restrictions on reuse than the AGPLv3 projects above.

Best for: teams already running a PHP/Laravel stack who want to bolt bulk sending onto an existing app rather than stand up a separate mail server.

web-bulk-email-sender (Flask)

The smallest project here: a Flask app with a web UI for sending personalized bulk or one-off emails, built around CSV recipient lists, HTML/Markdown/plain-text templates via a Quill.js editor, file attachments, and Python’s own smtplib for delivery. It’s MIT-licensed, with under a dozen GitHub stars, which is worth being upfront about. It’s a small side project, not battle-tested infrastructure, and there’s no mail server bundled in. You bring your own SMTP account.

Best for: a one-off campaign or a small list where standing up phpList or BillionMail would be overkill.

listmonk

listmonk is a self-hosted newsletter and transactional-email system written in Go with a Vue front end, distributed as a single binary for Linux, macOS, Windows, and BSD. It’s AGPLv3-licensed, and the project has documented running lists with millions of subscribers and sending over 7 million emails while staying lightweight on resources, using message queues and configurable rate limiting to manage large sends safely. As of its latest release (v6.2.0), it also supports SMS and WhatsApp sending alongside plain email, plus SQL-based list segmentation and a full HTTP API.

Best for: anyone who needs both newsletters and transactional email, like signup confirmations or alerts, from one system, and doesn’t mind that it’s a single Go binary rather than a PHP app.

Truly free vs. free-tier-limited: is each tool actually free?

Yes, for the software itself. All five projects here are free to download and run, and none of them cap how many emails you can send in the code. The one thing worth knowing before you pick one: phpList also sells a separate hosted product that works like a normal SaaS free tier, gates and all. That’s a different product from the free self-hosted software, and the distinction matters enough to walk through directly.

Checked against each project’s own repository and site in September 2026:

Tool	License	Self-hosted cost	Paid or hosted upsell	Sending cap in the software
phpList	AGPLv3	Free	phpList Ltd. also runs a hosted SaaS at phplist.com. Its own free (“Forever Free”) plan there withholds scheduling and repeat sending, message analytics, attachments, and multiple user accounts, and keeps “Powered by phpList” branding on outgoing mail, all features the self-hosted download includes for free	None
BillionMail	AGPLv3	Free	None found in the project’s repository or site	None. “Unlimited sending” is a marketing claim; real throughput depends on your server and SMTP relay, same as any tool on this list
Bulk-Email-Sender (Laravel)	MIT	Free	None found	None on sending. A 10,000-contact limit applies only to selecting “all filtered” contacts at once in the admin UI, not to how many emails go out
web-bulk-email-sender (Flask)	MIT	Free	None found	None
listmonk	AGPLv3	Free	None from the project itself. Some third-party companies host listmonk for a fee, which is a hosting service, not a feature the project gates	None. Rate limiting is a setting you configure, not a ceiling the software imposes

phpList needs the longer explanation, since it’s the one most likely to confuse anyone comparing “free” options here. Self-host phpList (the phplist3 code on GitHub, AGPLv3) and its own README confirms attachments, scheduling, pause/resume/repeat sends, and real-time analytics are all included, with no restriction. phpList Ltd. separately runs phplist.com, a hosted version of similar software, and that hosted product’s Forever Free plan does not include those same features: scheduling and repeat sending, detailed message analytics, attachments, and multiple user accounts are listed on phplist.com’s own pricing page as paid-tier features, and the free hosted plan carries “Powered by phpList” branding that paid plans remove. The gate is real. It’s just on phpList’s commercial hosted product, not on the free software you’d actually install on your own server.

The other four don’t have an equivalent. BillionMail, Bulk-Email-Sender, web-bulk-email-sender, and listmonk each ship as a single thing: the open-source project, with no companion commercial tier withholding a feature the free version also has.

A few more differences worth being exact about:

• Licensing matters if you’d ever run one of these as a service for other people. phpList, BillionMail, and listmonk are AGPLv3, which requires releasing your source changes if you offer a modified version over a network to other users. Bulk-Email-Sender and web-bulk-email-sender are MIT-licensed, with no such requirement.
• “Free” doesn’t mean zero cost. You still need a server, a domain with correct DKIM, SPF, and DMARC records, and either your own SMTP relay or a transactional-email provider’s API. None of that is included, and none of it is optional if you want mail landing in inboxes instead of spam folders.
• Community size differs sharply. BillionMail, phpList, and listmonk have far larger GitHub followings and commit histories than the other two. Bulk-Email-Sender and web-bulk-email-sender are smaller, less-tested projects, worth knowing if something breaks and you need to find a fix yourself rather than ask a maintainer.

How to choose what’s right for you

Your need	Recommended tool(s)
Proven tool for newsletters, segmentation, recurring campaigns	phpList, listmonk
Full mail server plus marketing layer, high-volume self-hosting	BillionMail, listmonk
Small campaigns or a simple newsletter, minimal setup	web-bulk-email-sender, Bulk-Email-Sender
Already running a PHP/Laravel stack	Bulk-Email-Sender, phpList
Need newsletters and transactional email from the same system	listmonk, BillionMail

Best practices and what to watch out for

• SMTP and deliverability come first. None of this software matters if your DKIM, SPF, and DMARC records aren’t set up correctly, or if your sending IP has no reputation. Self-hosted mail is unforgiving here in a way a SaaS provider usually hides from you.
• Handle opt-in and opt-out properly. Keep records of consent and honor unsubscribe requests immediately. This isn’t optional under GDPR or CAN-SPAM.
• Watch bounce and complaint rates. phpList and listmonk both handle bounce processing, and it’s worth actually using it. Ignoring bounces is one of the fastest ways to tank sender reputation.
• Segment instead of blasting your whole list. Smaller, targeted sends get better engagement and fewer spam complaints than one send to everyone.
• Size your infrastructure to your volume. A few hundred subscribers will run fine on a small VPS. Tens of thousands need real attention to your mail server, queueing, and database.

Conclusion

Between these five projects, most self-hosted bulk-email needs are covered: phpList for a mature, proven newsletter tool; BillionMail and listmonk for a full self-hosted stack at higher volume; and Bulk-Email-Sender or web-bulk-email-sender when you want something lighter, in PHP or Python respectively.

Marketing agencies managing multiple clients, in-house teams that don’t want to keep paying for list size, and anyone who’d rather keep subscriber data off a third party’s servers are the ones who get the most out of this approach. The trade-off is real too: you’re taking on the server setup, the deliverability tuning, and the ongoing maintenance that a SaaS vendor would otherwise handle for you.

References

• phpList / phplist3 (GitHub)
• phpList pricing (phplist.com hosted plan and feature comparison)
• aaPanel/BillionMail (GitHub)
• arafat-web/Bulk-Email-Sender (GitHub)
• SupratimRK/web-bulk-email-sender (GitHub)
• listmonk (project site)