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Email Marketing · head to head

Keila vs Substack

Keila logo

Keila

Email Marketing

AGPL newsletter tool from Germany, self-hostable or hosted in the EU with no free plan

From
Free
Rated
-
Full reviewWebsite
Substack logo

Substack

News

The newsletter platform for writers and publishers

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Keila there is no free hosted plan at all, stated as deliberate policy, so unlike almost every competitor there is no way to run a small list at zero cost without self-hosting it yourself.; Substack substack does not publish pricing on its public pricing page
  • They diverge on capability: Keila covers Priced by emails sent, Substack covers Newsletter publishing.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Keila and Substack actually diverge.

Attributes where Keila and Substack differ
AttributeKeilaSubstack
Pricing modelPer month by emails sentfreemium
PlatformsWeb, Linux, Self-hostedWeb, Mobile
CategoryEmail MarketingNews
FoundedUnknown2017

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Keila

  • Priced by emails sent
  • Bring your own sender
  • Self-hosting
  • EU hosting
  • Sign-up forms
  • Segmentation
  • Markdown and block editor
  • Multiple projects

Only in Substack

  • Newsletter publishing
  • Subscriber management
  • Paid subscriptions
  • Email analytics
  • Post scheduling
  • Archive creation
  • Free/paid tier split
  • Comments & discussion

What people use each for

The jobs each tool is most often brought in to do.

Keila

  • A membership organisation holding forty thousand contacts but sending only one newsletter a month, where contact-metered pricing would cost many times morenot Substack
  • A European publisher or public body that needs subscriber data held in the EU under a GDPR-friendly arrangementnot Substack
  • A technical team that wants to self-host its newsletter tool and route sending through its existing AWS SES accountnot Substack
  • An agency running several separate client lists that does not want to pay per project or per additional listnot Substack

Substack

  • Newsletter distributionnot Keila
  • Reader monetizationnot Keila
  • Community buildingnot Keila
  • Subscriber managementnot Keila

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Keila

  • There is no free hosted plan at all, stated as deliberate policy, so unlike almost every competitor there is no way to run a small list at zero cost without self-hosting it yourself.
  • Marketing automation is minimal, with none of the behavioural triggers, journey builders or e-commerce revenue attribution that Klaviyo, Brevo and Mailchimp treat as table stakes.
  • The self-hosted route puts deliverability entirely on you: reputation, SPF, DKIM, DMARC, warm-up and bounce handling are your problem, and a badly configured instance will land in spam folders.
  • It is a small project from a small company, so the integration ecosystem is thin and there is no partner network, template marketplace or large body of community expertise to draw on.
  • Email volume tiers step in fixed blocks, so an organisation whose sending is uneven across the year either overbuys at the annual peak or has to change plan repeatedly.

Substack

  • Substack does not publish pricing on its public pricing page

Pricing, plan by plan

Keila

Free
  • Self-hostedFree
    • AGPL-3.0-or-later licence with no fee
    • Official Docker image and sample compose file
    • You supply hosting and a sending backend
  • Keila XS$8/month
    • Two thousand emails per month
    • Unlimited contacts and projects
    • Send with Keila or bring your own email server
  • Keila M$32/month
    • Fifteen thousand emails per month
    • Unlimited contacts and projects
    • Sign-up forms and segmentation
  • Keila XXL$256/month
    • Two hundred and fifty thousand emails per month
    • Unlimited contacts and projects
    • Intermediate tiers at 16, 64 and 128 EUR for 5,000, 50,000 and 100,000 emails

Substack

Free
  • FreeFree
    • Unlimited newsletters
    • Basic design
    • Archive access
  • Pro$12/month
    • Custom domain
    • Advanced analytics
    • Member chat

Which should you pick?

Choose Keila if

  • You need priced by emails sent.
  • You want to start without paying.
  • You work on Web, Linux, Self-hosted.
  • You also want bring your own sender.
Keila review

Choose Substack if

  • You need newsletter publishing.
  • You want to start without paying.
  • You work on Web, Mobile.
  • You also want subscriber management.
Substack review

Questions people ask

Is Keila or Substack better?
Neither clearly leads. Keila starts at Free and Substack at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Keila or Substack?
Keila starts at Free and Substack at Free.
Does Keila or Substack run on more platforms?
Keila runs on Web, Linux, Self-hosted. Substack runs on Web, Mobile.
Can I use Keila for free?
Both have a free tier, so you can try either at no cost before committing.
What is Keila best used for?
Keila is most often used for a membership organisation holding forty thousand contacts but sending only one newsletter a month, where contact-metered pricing would cost many times more, a european publisher or public body that needs subscriber data held in the eu under a gdpr-friendly arrangement, a technical team that wants to self-host its newsletter tool and route sending through its existing aws ses account, an agency running several separate client lists that does not want to pay per project or per additional list. Of those, a membership organisation holding forty thousand contacts but sending only one newsletter a month, where contact-metered pricing would cost many times more and a european publisher or public body that needs subscriber data held in the eu under a gdpr-friendly arrangement are not what Substack is typically brought in for.
What can Keila do that Substack cannot?
Keila covers Priced by emails sent, Bring your own sender, Self-hosting, EU hosting. Substack covers Newsletter publishing, Subscriber management, Paid subscriptions, Email analytics.

Answered from the vendors’ own pages

Keila: Is Keila free?

The software is, under AGPL-3.0-or-later, if you self-host. The hosted service has no free plan by deliberate policy and starts at 8 EUR a month.

Substack: How much does Substack cost?

Substack does not publish rates on its pricing page. The site emphasizes earning potential for writers with the tagline Make money doing the work you believe in.

Source
Keila: How is the hosted service priced?

By emails sent, from 8 EUR for two thousand up to 256 EUR for two hundred and fifty thousand a month. Contacts and projects are unlimited on every tier.

Keila: Can I use my own email provider?

Yes. AWS SES, Sendgrid, Mailgun, Postmark, generic SMTP or a personal inbox are all supported as sending backends.

Keila: Are there discounts?

Pentacent offers reduced rates to nonprofits and open source projects on request.

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