Open-Source Email Marketing Tools: What's Worth Self-Hosting in 2026

Most people who look at open-source email marketing tools are running from a bill. A list that grew past a pricing tier, a plan that got restructured, a platform charging for contacts who have not opened anything in two years. Self-hosting looks like the exit: pay for a server, pay a fraction of a cent per email, keep the difference.

Sometimes that works. Sometimes you replace a $50 monthly invoice with six hours of DNS troubleshooting and a deliverability problem you cannot escalate to anyone. The gap between those two outcomes is mostly about which tool you pick and how honest you are about what you will actually maintain.

Here is what the open-source options do in 2026, what each one costs once you add up the parts, and where the break-even actually sits.

The Quick Picks

• Listmonk: newsletters and campaign blasts, nothing else. Lightest to run of anything here.
• Mautic: full marketing automation with lead scoring and visual campaign builders. Needs a real server.
• Ghost: publishing plus newsletters plus paid subscriptions in one product. The only one on this list where the free self-hosted version and the paid managed version are the same software.
• Plunk: transactional, workflow and campaign email behind one API. Youngest project here.
• Sendy: not open source, but the classic self-hosted-plus-SES setup, licensed once.

Every one of these needs a separate sending relay. That is the part people skip.

The Cost Nobody Puts on the Landing Page

Open-source email software does not send email. It manages lists, builds campaigns, and hands messages to an SMTP relay. You still pay someone to move the bytes.

Amazon SES is the usual answer at $0.10 per 1,000 emails, billed per recipient rather than per message. Send one campaign to 50,000 subscribers and that is 50,000 billable messages, or $5. Attachments add $0.12 per GB of data transfer, and a standard dedicated IP runs $24.95 per month if your volume justifies one.

SES is cheap and it is not friendly. You verify domains yourself, configure DKIM and SPF yourself, and request production access to leave the sandbox before you can send to unverified addresses. Bounce and complaint handling is your problem: SES will throttle or suspend an account with a bad complaint rate, and the warning arrives as an email from AWS, not a phone call. If you have never set up SPF, DKIM and DMARC from scratch, budget an afternoon.

Add the server. A small VPS runs $6–12 per month for most of these tools. Backups, monitoring and a CDN add more. Ghost’s own documentation estimates a full self-hosted setup at roughly $72 per month once you count hosting, email, CDN, analytics and backups, and Ghost is one of the better-documented projects here.

Listmonk

Listmonk is the one to look at first if your requirement is genuinely “send an email to a list on a schedule.” It is a single Go binary backed by PostgreSQL, AGPLv3-licensed, and it is absurdly light. It handles millions of emails on a footprint most tools would use just to boot. A 1 GB VPS is plenty.

Subscriber segmentation is done with SQL queries, which is either the best or worst thing about it depending on who you are. Someone comfortable with SELECT gets segmentation more precise than most SaaS platforms allow. Someone who is not will find no visual segment builder to fall back on.

The weakness is scope. Listmonk has no automation workflows, no A/B testing, no landing pages, and no drag-and-drop email builder. Support is a GitHub issue tracker. If your plan involves a welcome sequence that branches on behaviour, Listmonk is the wrong tool and no amount of configuration will fix that.

Best for: technical newsletter operators with large lists and simple sending needs. Full docs at listmonk.app.

Mautic

Mautic is the only project here that competes with ActiveCampaign on feature scope. Contact database with custom fields, drip sequences, behavioural triggers, lead scoring, landing pages, forms, visual campaign builders. It is a marketing automation platform, GPL-licensed, free to run.

The cost shows up in operations. Mautic wants 4–8 GB of RAM for a production install, plus PHP-FPM, a MySQL or MariaDB database, and a queue worker that has to keep running. That is a $30–50 per month server before you send anything, and it is a stack with several ways to break. Upgrades between major versions have historically required care.

Mautic makes sense when the alternative is a $200+ per month automation platform and you have someone who already administers PHP applications. It makes very little sense as a first self-hosted project.

Ghost

Ghost is a publishing platform with newsletters and paid subscriptions built in, and it is the cleanest exit path on this list because the self-hosted and managed versions are the same open-source software. You can start on Ghost(Pro), export everything, and self-host later without rewriting your site.

Ghost(Pro) Starter is $18 per month billed monthly, or $15 per month billed annually, covering up to 1,000 members with one staff user and one newsletter. Ghost takes 0% of subscription revenue, which matters if you are charging readers. That is the main argument against Substack and its revenue share.

Two real limitations. Newsletter sending is tied to Mailgun as the delivery provider, so “self-hosted” here still means an account with a specific vendor, and Mailgun no longer has a meaningful free tier. And the Starter plan is thin: no paid subscriptions, one user, one newsletter. Serious publications end up on a higher tier or self-hosting.

Analytics are also basic: the dashboard shows a rolling 90-day window and not much depth beyond it. Current plans are listed at ghost.org/pricing.

Plunk

Plunk is the newest project here and the most interesting architecturally: transactional email, automation workflows and campaign broadcasts all run against one contact list, triggered from a single API. Most stacks need two vendors to do that. It is AGPL-3.0, self-hostable, and built on top of SES.

Pricing on the hosted version is $0.001 per email with no contact limits, and the free tier covers 1,000 emails per month with Plunk branding. Charging per email rather than per contact is the right model for anyone sitting on a large, quiet list: the thing that makes Klaviyo and Mailchimp bills spike is contacts you are not even emailing.

The catch is maturity. There is no visual email editor and a thin template library, no A/B testing, no landing pages, no SMS. Support is a Discord server rather than a support team. Version 0.9.0 shipped in April 2026. This is a pre-1.0 project, and you should treat it as one. Pricing details are at useplunk.com/pricing.

Best for: developers who want one API for both product email and newsletters, and who can tolerate rough edges.

Sendy

Sendy is the odd one out. It is source-available, not open source. You buy a licence once, install it on your own server, and it sends through Amazon SES. Sendy’s site listed the licence at $69 as of July 2026; some resellers and review sites quote $59, so check the current figure at sendy.co before budgeting.

The economics are hard to argue with at volume. Unlimited subscribers, no per-contact tier, and SES sending costs of roughly $1 per 10,000 emails. A 100,000-subscriber list sending weekly costs about $40 per month in SES fees against a hosted platform bill in the high hundreds.

It shows its age. There is no drag-and-drop editor, so campaign design means HTML. No A/B testing, no landing pages, and automation is limited to basic autoresponders. It is a solo-developer product, and support response times reflect that. Sendy is a good answer to “I send a lot of similar emails to a very large list” and a poor answer to almost everything else.

Where Self-Hosting Stops Making Sense

For small lists it usually does not. The free tiers on hosted tools have tightened over the past year (MailerLite cut its free plan to 250 subscribers in June 2026) but they have not disappeared.

EmailOctopus is the clearest example of the middle ground: it runs on Amazon SES underneath, so you get SES economics, but someone else handles the infrastructure. The free plan covers 2,500 subscribers and 10,000 emails per month with EmailOctopus branding, and paid plans start at $9 per month at the smallest tier.

Its limits are real: no A/B testing, a small template library, basic automation, and no ecommerce features. But for a list under 5,000 it will cost less in money and time than any self-hosted setup, once you count your own hours.

The honest break-even sits somewhere around 25,000–50,000 subscribers for a plain newsletter, and higher if you need automation. Below that, hosted tools on SES infrastructure are hard to beat. Above it, per-contact pricing starts compounding fast enough that a server and an afternoon of setup pays for itself in a month.

How to Choose

Answer three questions honestly.

Do you need automation, or do you need to send campaigns? If branching workflows and behavioural triggers are load-bearing, your realistic open-source option is Mautic, with everything that implies about server size and maintenance. If you send broadcasts, Listmonk does that better and cheaper than anything.

Who fixes it at 11pm? Self-hosted email breaks in ways that are urgent: a queue stalls mid-campaign, a DKIM record expires, SES flags your complaint rate. If the answer is “nobody,” pick a hosted tool. This is not a failure of nerve; it is the single most common reason self-hosted email migrations get reversed.

Are you charging for the newsletter? If yes, Ghost is the strongest option here because subscription billing is native and the platform takes nothing. See our newsletter monetisation guide for the full picture.

If you are still weighing hosted alternatives, our cheapest email marketing tools roundup covers the low-cost SaaS end, and best tools for developers covers the API-first options that sit between self-hosting and a full marketing suite.

The Short Version

Listmonk if you send newsletters and can write SQL. Mautic if you need real automation and have a sysadmin. Ghost if readers pay you. Plunk if you want one API for everything and can live with a pre-1.0 product. Sendy if your list is enormous and your emails are simple.

And if your list is under a few thousand people, the tool that saves you the most is probably still a hosted one. Self-hosting is a trade, not a discount. You are paying in time instead of money, and time is the more expensive currency for most people running a newsletter alongside an actual job.

Sources

1. listmonk — Project site and documentation
2. Ghost — Pricing
3. Plunk — Pricing
4. Sendy — Licence and pricing