Open Source Marketing Automation: 5 Self-Hosted Tools for 2026
Open Source Marketing Automation: 5 Self-Hosted Tools for 2026
Mautic is the only genuinely full marketing automation platform that is open source, and it is GPL-3.0 and free to self-host. If you only need to send campaigns to a list rather than run behavioural automation, Listmonk is far lighter and does that job better. Those two cover most of this category. The rest of this guide covers three more, including one that appears on every open source roundup and is not open source.
The word "automation" is doing a lot of work in this category, and it is the first thing to get straight. Mautic tracks contacts across your site, scores them, and branches campaigns on behaviour. Listmonk, Keila and Mailtrain send email to lists. Those are different products for different problems, and picking the heavy one when you needed the light one is the most common mistake here.
Or own the front end: Email Marketing Kit
The Email Marketing Kit is a Next.js campaign and automation front end you buy once: subscriber and segment management, campaign builder, workflow automations, template editor and analytics screens. Next.js + Tailwind + shadcn/ui. You bring your own sending service. $149 solo, $249 team, $399 agency.
Get the Email Marketing Kit → or get every kit (18 total) for $749 via All UI Kits →
TL;DR: Which One
| What you need | Pick | Stack | Licence |
|---|---|---|---|
| Real automation: scoring, branching, behaviour | Mautic | PHP | GPL-3.0 |
| Send newsletters to big lists, fast and light | Listmonk | Go | AGPL-3.0 |
| A modern, friendly newsletter tool | Keila | Elixir | AGPL-3.0 |
| Cheapest possible sending, and not open source | Sendy | PHP | None named, $69 |
| A campaign front end inside your own product | Email Marketing Kit | Next.js | Commercial |
What Mautic Actually Costs
This is the question people arrive with, and the answer is split in a way Mautic's own site does not make obvious.
Self-hosting Mautic is free. The software is GPL-3.0 and the download is public, so your cost is a server, a database and a sending service, not a licence. For a modest list that is realistically $20 to $60 a month of hosting plus whatever Amazon SES or similar charges you to send.
Managed Mautic is not cheap. Confusingly, mautic.org/pricing does not show the price of Mautic. It shows Managed Mautic, a hosted service offered by Dropsolid, Mautic's official hosting partner, and the prices there are for that service rather than for the software:
| Plan | Price | Includes |
|---|---|---|
| Essential | From €247.50/mo billed annually (€275 quarterly) | Up to 50K emails/month, up to 50K contacts, shared IP |
| Professional | From €1,237/mo | Dedicated hosting and IP, from 50K emails/month |
| Enterprise | Custom | Up to 6M emails/month, SSO |
Mautic states that 40% of that revenue goes back to the community, which is a reasonable thing to know if you are choosing between hosting it yourself and paying for it.
One correction worth making, because it turns up constantly: Acquia does not own Mautic. Acquia appears on mautic.org as one of three partners, alongside Webmecanik and Leuchtfeuer. The trademark belongs to the Mautic project of the Open Source Collective, and governance runs through community council pages.
Which of These Are Actually Alive
For software you will host yourself, the repository is better evidence than any review site. Pulled from the GitHub API on 23 September 2026:
| Project | Stars | Open issues | Last push | Language | Licence |
|---|---|---|---|---|---|
| Listmonk | 23,528 | 119 | 13 Sep 2026 | Go | AGPL-3.0 |
| Mautic | 10,540 | 209 | 22 Sep 2026 | PHP | GPL-3.0 |
| Mailtrain | 5,754 | 116 | 5 Oct 2025 | JavaScript | GPL-3.0 |
| Keila | 2,218 | 79 | 21 Sep 2026 | Elixir | AGPL-3.0 |
Three of the four shipped code within the last two weeks. Mailtrain has not been pushed to in nearly a year, which is the one date on this page worth acting on.
Note that Listmonk has more than twice Mautic's stars while doing far less, which tells you something real about what people actually want from this category: most teams want to send email to a list without operating a marketing automation platform.
1. Mautic
The only open source product that genuinely competes with HubSpot or ActiveCampaign on capability rather than on sending.
Strengths:
- Real automation: contact tracking, lead scoring, branching campaign builder
- Landing pages, forms and dynamic content included
- GPL-3.0, no contact limits, no per-send licence
- Actively developed with a real governance structure behind it
Weaknesses:
- Heavy. PHP, a database, cron, and a queue, and it wants maintenance
- The learning curve is the real cost, not the hosting
- Deliverability is entirely your problem
- Overkill if you only send newsletters
Best for: Teams who need behavioural automation and have someone who will own the installation.
2. Listmonk
A single Go binary that sends a lot of email to a lot of people, quickly. The most popular project in this category by stars, and the one most people should start with.
Strengths:
- Single binary plus Postgres, which is about as easy as self-hosting gets
- Genuinely fast on large lists
- Clean admin UI, good templating, solid API
- AGPL-3.0 and free, with no contact tiers
Weaknesses:
- Lists and campaigns, not behavioural automation
- No landing pages or forms builder
- You still bring and manage a sending service
Best for: Newsletters and product announcements at any list size, when automation is not the requirement.
3. Keila
The newest and friendliest of these. Elixir, which is an unusual choice that suits email sending well.
Strengths:
- The nicest interface of the open source options
- AGPL-3.0, self-host or use their hosted version
- Sensible defaults, quick to get running
Weaknesses:
- Much smaller community than Listmonk or Mautic
- Elixir is a real constraint if nobody on the team knows it
- Fewer integrations and less third-party material to lean on
Best for: Small teams who want something pleasant rather than something maximal.
4. Mailtrain
Node-based newsletter software that was a common recommendation and now needs a caveat.
Its repository was last pushed on 5 October 2025, nearly a year before this was written, while Listmonk, Mautic and Keila all shipped within the last fortnight. It is not archived, and it may well still run fine. But for software that sits between you and your subscribers, and that handles unsubscribes and bounces, a year of silence is a reason to pick something else for a new deployment.
Best for: Existing installations. Not new ones.
github.com/Mailtrain-org/mailtrain
5. Sendy, Which Is Not Open Source
Sendy appears on nearly every open source email list. It is not open source, and it does not claim to be.
Sendy's own site describes it as self-hosted software with a one-time $69 fee, licensed per domain, and never names an open source licence. Free updates run only until the next major version. It is PHP and MySQL, it sends through Amazon SES, and that combination is genuinely the cheapest way to send bulk email at volume.
One small thing to check yourself: Sendy's homepage quotes its sending cost as both "$1.6 per 10,000 emails" and "$1 per 10,000 emails" in different places on the same page. The real number depends on SES pricing in your region either way.
So Sendy belongs in this comparison, just not under the word "open source". If your requirement is cheap, it qualifies easily. If your requirement is that you can read and modify the code, it does not.
Build the Front End: Email Marketing Kit
If what you actually want is campaign management inside your own product rather than a separate tool on a subdomain, the Email Marketing Kit is that front end already built: subscriber and segment management, campaign builder, automation workflows, template editor and analytics.
It is a frontend kit. You bring the sending service, Amazon SES or Resend or Postmark, and the database. $149 solo, $249 team, $399 agency. Or every kit (18 total) for $749 via All UI Kits.
Get the Email Marketing Kit → or See All UI Kits →
Frequently Asked Questions
What is the best open source marketing automation tool?
Mautic, if you mean automation in the real sense of contact tracking, lead scoring and behavioural campaign branching. It is the only open source product competing at that level, and it is GPL-3.0 with no contact limits. If you only need to send campaigns to a list, Listmonk is lighter, faster and considerably easier to run.
Is Mautic free?
Yes, if you host it. Mautic is GPL-3.0 and the download is public, so there is no licence fee and no contact tier. You pay for a server, a database and a sending service. The prices on mautic.org are for Managed Mautic, a hosted service from their partner Dropsolid, which starts at €247.50 a month billed annually. Those are two different things and the site does not separate them clearly.
How much does Mautic cost per month?
Self-hosted, realistically $20 to $60 a month of hosting for a modest list, plus sending costs through something like Amazon SES. Managed Mautic through Dropsolid starts at €247.50 a month billed annually for up to 50,000 emails and 50,000 contacts, rising to €1,237 for the Professional tier.
Is Sendy open source?
No. Sendy is self-hosted software sold for a one-time $69 fee, licensed for one domain, and its site never names an open source licence. It gets listed as open source constantly because self-hosted and open source get used interchangeably, but you cannot read or modify its source. If free-to-licence is what you need, look at Listmonk or Mautic instead.
What are the best Sendy alternatives?
Listmonk is the closest in spirit and is free: same self-hosted model, same idea of sending cheaply through your own provider, but AGPL-3.0 with source you can read. Keila is the friendlier option if the interface matters more than raw throughput. Mautic if you need automation rather than sending. All three remove Sendy's per-domain licence entirely.
What is the best self-hosted Mailchimp alternative?
Listmonk for most people, because Mailchimp's core job for the majority of its users is sending campaigns to a list, and Listmonk does that without per-contact pricing. Choose Mautic instead if you use Mailchimp's automation and journey features rather than just its campaigns. Either way the saving is real, since both price on your server rather than your list size.
Listmonk or Mautic: which should I pick?
Decide by whether you need behaviour. If your emails go out to a list on a schedule or when you publish something, that is Listmonk, and it will be dramatically less work to run. If you need to react to what contacts do, score them, and branch a campaign based on that, only Mautic does it. Do not run Mautic for newsletters, and do not try to make Listmonk do automation.
