Open-source email newsletter tool, honestly reviewed. No marketing fluff, just what you actually get when you deploy it.

TL;DR

What it is: Open-source (AGPL-3.0) email newsletter platform — think Mailchimp, but the software runs on your server and your subscriber list is nobody else’s asset [1][2].
Who it’s for: Non-technical founders, creators, and advocacy organizations who want Mailchimp-style simplicity, GDPR-friendly EU infrastructure, and no per-contact pricing that scales against you [2].
Cost savings: Mailchimp’s Standard plan starts around $20/month for 500 contacts and climbs steeply — 10,000 contacts runs $100+/month. Keila self-hosted runs on a $5–10/mo VPS with no contact limits [2].
Key strength: Multiple first-class editor options — block editor, Markdown WYSIWYG, MJML, plain text — in a single tool, without forcing you to upgrade tiers to access them [2]. Privacy-conscious analytics you can turn off entirely.
Key weakness: 2,042 GitHub stars is a modest community for a category where Listmonk and Mautic have substantially larger followings. Third-party review coverage is thin, which makes it harder to judge real-world stability at scale. AGPL-3.0 license adds legal complexity if you’re building a product on top of it.

What is Keila

Keila is an email newsletter platform built in Elixir [2], made by the German company Pentacent, and designed to replace Mailchimp or Brevo for teams who want to own their subscriber data and stop paying per-contact fees. The mascot is an elephant named Keila — the naming choice is functionally honest: “a wise and diligent elephant lady, able to remember countless email addresses and contact names” [1].

The pitch is simple: self-host it, connect it to your own email sending provider (or a transactional email API), and send campaigns without any platform taking a cut of your list size or setting a ceiling on how many emails you can fire per month [2].

What separates Keila from the herd of self-hosted newsletter tools is a combination of things that don’t usually coexist: a genuinely clean interface built for non-developers, four editor types (block, Markdown, MJML, plain text) that coexist without feature-gating, and EU-native infrastructure on their managed cloud that speaks directly to GDPR concerns [2]. The project sits at 2,042 GitHub stars — not huge, but steady — and it’s backed by a commercial entity that runs Keila Cloud as a managed offering, which is usually a healthier signal than a pure volunteer project [1][2].

The AGPL-3.0 license is worth understanding upfront: this is “true” open source with no proprietary premium features, but it carries a network-service obligation that MIT does not. If you self-host Keila and modify it, you must make those modifications available to users of the service. For a solo founder running their own newsletter, this doesn’t matter at all. For an agency offering Keila as a managed service to clients, it requires a compliance check [1].

Why people choose it

Without broad third-party review coverage available for this tool, the signal comes primarily from testimonials on the official site and the logic of the category positioning. Those testimonials are worth reading literally rather than as marketing filler.

Anouk Ooms, General Secretary at Volt Europa — a pan-European political party — says: “Keila has helped us send millions of emails to subscribers all across Europe while keeping full control of our data.” [2] That’s a meaningful endorsement from an organization for whom GDPR compliance and data sovereignty aren’t nice-to-haves, they’re operational requirements.

André Hoarau, creator of Brinjel, is blunter: “Simple, no-fuss UI. No-tracking feature. Awesome support. Written in Elixir. AGPL-licensed. Hosted in the EU. The right tool for the job!” [2] This kind of review, from someone who clearly evaluated alternatives, hits the checklist that recurs in the self-hosted email category: license clarity, UI simplicity, hosting jurisdiction.

Amadeus Paulussen adds: “My team and I have sent hundreds of client newsletters with various tools over the past 20 years. Today, I recommend Keila because it’s a joy to use, has excellent support, it’s open source, and feels much more in line with what’s important to me.” [2]

The pattern across these is consistent: users with real sending history picking Keila specifically for values alignment (open source, EU, no tracking, data ownership) plus a UI that doesn’t require training people.

The Mailchimp comparison is direct. Mailchimp’s pricing model is the pain being escaped: free up to 500 contacts, then paid tiers that scale with contact count — not just with how often you send. A 10,000-subscriber list on Mailchimp Standard costs around $100/month regardless of whether you send weekly or monthly. Keila removes that variable entirely: self-hosted means your contact count is bounded only by your VPS’s RAM, not by a pricing tier [1][2].

The GDPR angle is real, not marketing. For European organizations or any company with EU subscribers, the fact that Keila Cloud runs entirely on European infrastructure (Germany and France) eliminates a class of compliance conversations that Mailchimp and its US-headquartered competitors create [2].

Features

Based on the official documentation and website:

Editor options — four of them, all included:

Visual block editor with multi-column layout support [2]
Markdown with WYSIWYG preview [2]
MJML (the email-specific markup language) for full custom responsive layouts [2]
Plain text for the no-HTML crowd [2]

This is non-trivial. Most newsletter tools give you one editor and make you live with it. Keila lets a non-technical marketer use the block editor and a developer write MJML in the same account.

Contact management and forms:

Sign-up form builder with custom fields: checkboxes, text fields, dropdowns [2]
Captcha protection on forms [2]
Double opt-in verification [2]
Segments based on contact data, tags, or language preferences — with both a visual editor and a query language for complex cases [2]

Personalization:

Liquid template language (the same engine Shopify uses) for dynamic content [2]
Custom data per contact as a JSON object — you can push data from a CMS or CRM and reference it in templates [2]
Per-campaign custom data for batch-specific variable content [2]

Analytics:

Standard campaign metrics [2]
Privacy-configurable: you can reduce tracking or turn it off entirely [2]
No “collect more than is necessary” approach — the framing on the website is explicit about this [2]

Infrastructure and integrations:

Docker image (pentacent/keila) with sample Docker Compose config [1]
Email sender support: own SMTP, AWS SES, Sendgrid, Mailgun, Postmark [1]
REST API for managing contacts and campaigns programmatically [2]
Zapier integration — listed as private beta at time of research [2]

What’s missing:

No A/B testing mentioned in official materials
No native landing page builder
Automation / drip sequences are not highlighted in available documentation — this is a gap compared to full marketing automation tools like Mautic
The Zapier integration being in private beta means “low-code integration” is aspirational, not shipped

Pricing: SaaS vs self-hosted math

Keila Cloud pricing: The pricing page exists at https://www.keila.io/pricing, but specific tier price points were not captured in research materials for this review [3]. Contact the official site for current numbers.

Self-hosted:

Software cost: $0 (AGPL-3.0) [1]
VPS: $5–10/month on Hetzner or equivalent
Email sending: transactional API costs (AWS SES is ~$0.10 per 1,000 emails; Mailgun and Sendgrid have free tiers)

Mailchimp for comparison:

Free: 500 contacts, 1,000 emails/month
Essentials: ~$13/month at 500 contacts, scaling to $350/month at 50,000
Standard: ~$20/month at 500 contacts, $100+/month at 10,000 contacts
Premium: from ~$350/month

Brevo (formerly Sendinblue) for comparison:

Free: unlimited contacts, 300 emails/day cap
Starter: from ~$25/month for 20,000 emails/month
Business: from ~$65/month

Concrete savings math: A newsletter with 5,000 subscribers sending weekly (20k emails/month) costs roughly $50–75/month on Mailchimp Standard. Self-hosted Keila on a $6 Hetzner VPS plus AWS SES at $0.10/1,000 emails comes to about $8/month — $6 VPS plus $2 in SES costs. That’s roughly $500–800 saved per year, before the list grows further. As your list scales, Mailchimp’s bill scales; Keila’s doesn’t.

Deployment reality check

What you need:

A Linux VPS (2GB RAM minimum; 4GB comfortable)
Docker and Docker Compose
PostgreSQL and a mail sending provider (SMTP, AWS SES, Sendgrid, Mailgun, or Postmark) [1]
A domain with DNS you control for sending reputation

The actual process: Keila provides an official Docker image and a sample Docker Compose config in the repo [1]. The installation documentation at https://www.keila.io/docs/installation walks through the process. For someone who has deployed a Docker container before, this is a 30–60 minute job. For someone who hasn’t, budget 2–4 hours including domain setup and email provider configuration.

What can go sideways:

Email deliverability is entirely your responsibility. Getting a new sending domain off spam filters requires SPF, DKIM, and DMARC configuration — Keila doesn’t do this for you, and it’s the part most likely to trip non-technical users.
The AGPL license creates a compliance obligation if you’re running Keila as a service for paying clients — understand this before you build your agency offering on it [1].
2,042 GitHub stars is a real number to sit with. The project is actively maintained and has a commercial backer, but if you’re planning to send millions of emails to critical audiences, you’ll want to test at realistic volumes first.

Pros and cons

Pros

No per-contact pricing, ever. Self-hosted Keila has no artificial list-size ceiling. Your costs scale with your VPS and your email sending provider, both of which are orders of magnitude cheaper than Mailchimp at any real list size [1][2].
Four editors in one. Block editor for non-technical users, MJML for developers who want pixel-precise responsive templates, Markdown for writers who want friction removed, plain text for minimalists. No other tool in this category offers all four without tiering [2].
100% open — no open-core tax. AGPL-3.0 means every feature is available in the self-hosted version. There’s no “advanced analytics” or “team seats” plan gating basic functionality [1][2].
Privacy-first analytics architecture. You can turn off tracking entirely. For GDPR compliance and privacy-conscious audiences, this is not a minor detail [2].
EU infrastructure on managed cloud. For European orgs, the legal simplicity of European-only hosting is worth real money in compliance overhead [2].
Liquid templates + custom contact JSON. This is a genuinely powerful personalization model that most newsletter tools don’t offer at this price point [2].
Actively maintained with commercial backing. Pentacent runs Keila Cloud, which means there’s revenue aligned with keeping the project healthy [2].

Cons

Thin third-party review coverage. There is not yet the ecosystem of independent user reviews, migration guides, and comparison articles that tools like Listmonk or Mailchimp have. Harder to judge edge-case behavior from external sources.
2,042 stars is modest. The community is smaller than alternatives like Listmonk (14k+ stars). Smaller community means fewer community-contributed templates, fewer Stack Overflow answers, fewer people who’ve solved your specific problem before you.
No native drip/automation. Keila handles campaigns and one-time sends well. If you need behavior-triggered sequences (“send email 3 days after signup if they haven’t clicked”), that’s not highlighted in current documentation [2].
AGPL requires careful reading for commercial use. If you want to run Keila as a managed service for clients and you’ve made modifications to the codebase, you’re obligated to publish those changes [1]. Fine for most users; potentially a barrier for agencies.
Zapier integration still in private beta at time of research. The “low-code connection to your other tools” story isn’t fully shipped yet [2].
Pricing page not scraped. Cloud pricing was not available in research materials — you’ll need to visit the site directly.

Who should use this / who shouldn’t

Use Keila if:

You’re a European organization with GDPR obligations and you want infrastructure that doesn’t create transatlantic data flow conversations.
You’re a creator or founder paying $50–100/month to Mailchimp and tired of watching the bill grow as your list does.
You have someone who can deploy a Docker container (or can pay someone once to do it), and you want to own your data after that.
You want to offer both a visual block editor to non-technical teammates and full MJML control to a developer, in the same tool.
Privacy-conscious newsletters where you want analytics you can turn off entirely.

Skip it (try Listmonk instead) if:

You want a more battle-tested self-hosted option with a larger community and MIT license. Listmonk has 16k+ stars and an API-first design that’s popular with developers.
You’re building a high-volume transactional newsletter pipeline. Listmonk’s architecture is optimized for throughput.

Skip it (stay on Mailchimp or Brevo) if:

You need mature automation sequences and behavior-triggered campaigns out of the box, and you’re not willing to wait for them to ship.
You have no one who can manage a Linux VPS, and you can’t afford a one-time deployment.
Your legal team won’t approve self-hosted infrastructure handling subscriber PII.

Skip it (try Mautic instead) if:

You need full marketing automation: lead scoring, CRM integration, multi-channel campaigns, and drip sequences. Mautic is heavier and more complex, but it covers the automation layer that Keila currently doesn’t prioritize.

Alternatives worth considering

Listmonk — Go-based, MIT license, API-first, 14k+ GitHub stars. The developer-preferred choice. Less polished UI than Keila; significantly larger community.
Mautic — Full marketing automation platform. Open source, self-hosted, with CRM features, drip sequences, and lead scoring. Much heavier to operate; overkill for a pure newsletter use case.
Sendy — PHP-based, one-time license fee (~$69), tightly coupled to AWS SES. Good for high-volume senders on a budget; closed source.
Mailchimp — The incumbent. Best-in-class deliverability tooling and integration catalog; expensive at scale; no self-hosting option; US-based infrastructure.
Brevo (Sendinblue) — More affordable than Mailchimp for high-send-volume scenarios; unlimited contacts on free plan; SaaS-only; closed source.
Buttondown — SaaS-only, writer-focused, Markdown-native. No self-hosting, but excellent deliverability and a clean interface for solo newsletter authors.

For a non-technical European founder choosing between self-hosted options, the realistic shortlist is Keila vs Listmonk. Pick Keila if UI polish, multiple editor types, and EU-first positioning matter. Pick Listmonk if community size and developer ergonomics matter more than UI.

Bottom line

Keila is what Mailchimp should have been for organizations that care about data ownership: a clean, multi-editor newsletter tool with no per-contact fees, EU-native infrastructure, and a 100% open-source model that hides nothing behind a paid tier. The AGPL license and 2,042-star community are honest constraints — this isn’t Mailchimp’s feature breadth or Listmonk’s community depth — but for its target audience (European orgs, privacy-conscious creators, and founders paying $100+/month for a list they don’t own), the trade-off is straightforward. A VPS, an afternoon of setup, and you’ve eliminated a bill that only ever grows while putting your subscriber data back on infrastructure you control.

If the setup is the blocker, that’s exactly the kind of one-time deployment that upready.dev handles for clients.

Sources

Keila GitHub Repository — pentacent/keila, AGPL-3.0, 2,042 stars. https://github.com/pentacent/keila
Keila official website — features, testimonials, homepage. https://www.keila.io
Keila pricing page — Cloud pricing tiers. https://www.keila.io/pricing
Keila installation documentation — Self-hosting guide, Docker setup. https://www.keila.io/docs/installation