Softwr

Email Marketing · head to head

Sailthru vs Substack

Sailthru logo

Sailthru

Email Marketing

Retail and publisher email personalisation, now one product inside the Marigold portfolio

From
On request
Rated
-
Full reviewWebsite
Substack logo

Substack

News

The newsletter platform for writers and publishers

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Substack has a free tier, so it costs nothing to try first.
  • Each has a real cost: Sailthru the product sits in a portfolio with several overlapping platforms under one owner, so roadmap investment is a portfolio decision rather than a product decision and is worth asking about in writing.; Substack substack does not publish pricing on its public pricing page
  • They diverge on capability: Sailthru covers Interest profiles, Substack covers Newsletter publishing.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Sailthru and Substack actually diverge.

Attributes where Sailthru and Substack differ
AttributeSailthruSubstack
Starting priceOn requestFree
Pricing modelquotefreemium
Free tierNoYes
PlatformsWeb, REST APIWeb, Mobile
CategoryEmail MarketingNews
FoundedUnknown2017

Identical on both: 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 Sailthru

  • Interest profiles
  • Personalisation engine
  • Prediction Manager
  • Site personalisation
  • Zephyr templating
  • Lifecycle optimiser

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.

Sailthru

  • A publisher sending a personalised daily newsletter assembled per reader from a content cataloguenot Substack
  • A retailer that wants email and on-site recommendations driven by the same affinity modelnot Substack
  • High-cadence sending where per-recipient content assembly matters more than journey branchingnot Substack
  • Teams that want churn and lifetime value scores available as native campaign conditions rather than imported fieldsnot Substack

Substack

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

Where each one falls short

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

Sailthru

  • The product sits in a portfolio with several overlapping platforms under one owner, so roadmap investment is a portfolio decision rather than a product decision and is worth asking about in writing.
  • Pricing counts stored profiles, so retained inactive readers keep costing money long after they stopped opening anything.
  • On-site personalisation requires a developer to implement the JavaScript and maintain the content feed, which puts the highest-value feature behind engineering time.
  • Zephyr is a proprietary templating language, so template maintenance skills are scarce compared with the Liquid syntax used by most competitors.
  • It is built for high-cadence content and retail sending, and B2B lifecycle programmes with long sales cycles sit poorly on the model.

Substack

  • Substack does not publish pricing on its public pricing page

Pricing, plan by plan

Sailthru

On request
  • Sailthru$undefined/year
    • Priced on stored profiles and send volume
    • Site personalisation and prediction features licensed by module
    • Annual contract through Marigold

Substack

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

Which should you pick?

Choose Sailthru if

  • You need interest profiles.
  • You work on Web, REST API.
  • You also want personalisation engine.
Sailthru 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 Sailthru or Substack better?
Neither clearly leads. Sailthru starts at On request and Substack at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Sailthru or Substack?
Substack has a free tier; the other does not. Paid plans start at On request for Sailthru and Free for Substack.
Does Sailthru or Substack run on more platforms?
Sailthru runs on Web, REST API. Substack runs on Web, Mobile.
Can I use Substack for free?
Yes. Substack has a free tier, so you can try it without paying. Sailthru starts at On request.
What is Sailthru best used for?
Sailthru is most often used for a publisher sending a personalised daily newsletter assembled per reader from a content catalogue, a retailer that wants email and on-site recommendations driven by the same affinity model, high-cadence sending where per-recipient content assembly matters more than journey branching, teams that want churn and lifetime value scores available as native campaign conditions rather than imported fields. Of those, a publisher sending a personalised daily newsletter assembled per reader from a content catalogue and a retailer that wants email and on-site recommendations driven by the same affinity model are not what Substack is typically brought in for.
What can Sailthru do that Substack cannot?
Sailthru covers Interest profiles, Personalisation engine, Prediction Manager, Site personalisation. Substack covers Newsletter publishing, Subscriber management, Paid subscriptions, Email analytics.

Answered from the vendors’ own pages

Sailthru: Who owns Sailthru now?

Marigold, formerly CM Group, which also owns Campaign Monitor, Emma, Selligent, Liveclicker and Cheetah Digital.

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
Sailthru: Does that affect the roadmap?

It can. Overlapping products in one portfolio compete for investment, so ask which platform is the strategic one for your segment before signing multi-year.

Sailthru: Is it worth it just for newsletters?

For personalised daily newsletters at publisher scale it remains one of the strongest options. For simple broadcast sending it is heavily over-specified.

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