Softwr

Email Marketing · head to head

Instantly vs Sailthru

Instantly logo

Instantly

Email Marketing

Cold email outreach platform with AI, lead sourcing, and mailbox rotation

From
Free
Rated
-
Full reviewWebsite
Sailthru logo

Sailthru

Email Marketing

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

From
On request
Rated
-
Full reviewWebsite

The short version

  • Only Instantly has a free tier, so it costs nothing to try first.
  • Each has a real cost: Instantly shared mailbox rotation could expose sender reputation to other users' poor practices; domain reputation can degrade rapidly if co-users violate sending norms; 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.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Instantly and Sailthru actually diverge.

Attributes where Instantly and Sailthru differ
AttributeInstantlySailthru
Starting priceFreeOn request
Pricing modelfreemiumquote
Free tierYesNo
PlatformsWeb, APIWeb, REST API

Identical on both: user rating (Not yet rated), category (Email Marketing).

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 Instantly

Nothing recorded that Sailthru does not also cover.

Only in Sailthru

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

What people use each for

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

Instantly

  • SaaS sales teams automating cold outreach and lead qualificationnot Sailthru
  • Digital agencies and freelancers running campaigns for multiple clientsnot Sailthru
  • E-commerce and B2B businesses prospecting at scalenot Sailthru
  • Recruitment agencies sourcing candidates via emailnot Sailthru
  • Partnerships and channel sales automating partner outreachnot Sailthru
  • Financial services and insurance lead generationnot Sailthru

Sailthru

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

Where each one falls short

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

Instantly

  • Shared mailbox rotation could expose sender reputation to other users' poor practices; domain reputation can degrade rapidly if co-users violate sending norms
  • AI campaign generation, whilst useful, produces generic copy; personalisation still requires manual review and editing for high-quality outreach
  • Email as primary channel faces declining effectiveness; spam filtering improves and email open rates decline generally
  • Lead database quality varies; verification filters may miss invalid addresses or outdated contacts
  • Freemium model limits features significantly; advanced analytics, API access, and priority support require paid tiers

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.

Pricing, plan by plan

Instantly

Free

No published plan breakdown. See the Instantly review.

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

Which should you pick?

Choose Instantly if

  • You want to start without paying.
  • You work on Web, API.
Instantly review

Choose Sailthru if

  • You need interest profiles.
  • You work on Web, REST API.
  • You also want personalisation engine.
Sailthru review

Questions people ask

Is Instantly or Sailthru better?
Neither clearly leads. Instantly starts at Free and Sailthru at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Instantly or Sailthru?
Instantly has a free tier; the other does not. Paid plans start at Free for Instantly and On request for Sailthru.
Does Instantly or Sailthru run on more platforms?
Instantly runs on Web, API. Sailthru runs on Web, REST API.
Can I use Instantly for free?
Yes. Instantly has a free tier, so you can try it without paying. Sailthru starts at On request.
What is Instantly best used for?
Instantly is most often used for saas sales teams automating cold outreach and lead qualification, digital agencies and freelancers running campaigns for multiple clients, e-commerce and b2b businesses prospecting at scale, recruitment agencies sourcing candidates via email. Of those, saas sales teams automating cold outreach and lead qualification and digital agencies and freelancers running campaigns for multiple clients are not what Sailthru is typically brought in for.
What can Instantly do that Sailthru cannot?
Sailthru covers Interest profiles, Personalisation engine, Prediction Manager, Site personalisation.

Answered from the vendors’ own pages

Instantly: Is Instantly free?

Instantly offers a freemium model. No credit card is required to start. Free tier includes basic lead finding and campaign creation; paid tiers unlock advanced features (API access, advanced analytics, priority support).

Source
Sailthru: Who owns Sailthru now?

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

Instantly: How does Instantly's AI Copilot work?

AI Copilot generates email copy, subject lines, and follow-up sequences based on brief campaign descriptions. Users can customise generated templates before sending.

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.

Instantly: What CRMs does Instantly integrate with?

Instantly integrates with Salesforce, HubSpot, Pipedrive, and Zapier. Custom integrations via REST API are available on paid plans.

Source
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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