If you are emailing people who subscribed, you want an opt-in platform, and the best one depends on whether you run ecommerce, a newsletter or general small-business marketing. If you are emailing people who never subscribed, none of those platforms will let you, and you need outbound infrastructure instead.
Published by emailcampaign.ai, which is a tool in the second category and not in the first. We have no commercial interest in which opt-in platform you pick, and we recommend them plainly below.
Which job are you in?
One question settles it: did these people ask to hear from you?
If yes, you are doing email marketing. The recipients subscribed, you send from one domain and one platform, and volume per send is high. If no, you are doing cold outreach. The recipients have no relationship with you, sending is spread across many mailboxes, and volume per identity is single digits per day.
The two need different infrastructure for a reason that is structural rather than commercial, covered further down.
Opt-in platforms, by what they are actually good at
| Use case | Commonly chosen | Why |
|---|---|---|
| Ecommerce | Klaviyo, Omnisend | Deep store integrations, behavioural triggers, abandoned cart flows |
| Newsletters and creators | Beehiiv, Kit | Built for publishing and monetising an audience rather than selling a product |
| General small business | Mailchimp, Brevo | Broad feature set, gentle learning curve, usable free tiers |
| Enterprise with a CRM | HubSpot | Email tied natively to pipeline and customer records |
Within a category the differences are smaller than the marketing suggests. Pick on the integration you actually need and on how your list size affects the bill, since most of these price by subscriber count.
Why those apps refuse cold outreach
This is the part that surprises people, so it is worth being precise about the mechanism rather than just quoting terms of service.
Opt-in platforms send from shared IP pools. Many customers send from the same addresses, so the reputation of that pool is collective. If one customer sends to a list nobody consented to and collects complaints, placement degrades for every other customer on the pool.
That is why their terms prohibit sending to addresses that did not opt in, and why enforcement is a suspension rather than a warning. It is not a policy preference, it is protection of an asset shared with thousands of other businesses.
What cold outreach needs instead
Its own domains, its own mailboxes, and warm-up per mailbox. The unit of work is not the campaign, it is the mailbox, which is why outbound tools look strange to someone arriving from inbound marketing.
| Email marketing | Cold outreach | |
|---|---|---|
| Recipients | Subscribed | Never heard from you |
| Sending identity | One domain, one platform | Many mailboxes across separate domains |
| Volume per identity | Thousands per send | Eight to ten a day |
| Infrastructure | Shared or dedicated IP pool | Provider mailboxes, warmed individually |
| Priced by | Subscriber count | Sending volume or seats, plus mailboxes |
| Primary metric | Clicks and revenue per send | Replies and meetings booked |
If you need a shortlist for the second category, we compared eight outbound tools on price, who supplies the mailboxes, and the catch for each, including our own limitation.
The cost line people miss
For opt-in platforms, cost scales with list size, so a growing list raises the bill whether or not you send more.
For cold outreach, the platform is the small part. A hundred Google Workspace mailboxes is roughly $840 a month before any software, which typically runs $32 to $94. Teams that compare outbound tools on monthly price alone are comparing about five percent of what they will actually spend.
A short way to decide
- Did they subscribe? If yes, pick from the table above on integrations and list-size pricing.
- If no, you need outbound infrastructure, and the first question to ask any vendor is who owns the domains when you leave.
- If you are doing both, keep them on separate domains. Transactional and marketing mail should never share a sending reputation with cold outreach.
Questions, answered straight
- Which app is best for email marketing?
- It depends on the job. For ecommerce and behavioural automation, Klaviyo and Omnisend lead. For newsletters and creators, Beehiiv and Kit. For broad small-business marketing, Mailchimp and Brevo. For cold outbound to people who never subscribed, none of those, because they prohibit it.
- Can I use Mailchimp or Klaviyo for cold email?
- No. Their terms prohibit sending to addresses that did not opt in, and they enforce it by suspending accounts. They send from shared IP pools, so one customer's complaint rate affects every other customer's placement. Cold outreach needs its own domains and mailboxes.
- What is the difference between email marketing and cold email tools?
- Email marketing tools optimise for sending a lot from one identity to people who subscribed. Cold email tools optimise for sending a little from many identities to people who did not. The unit of work is the campaign in one and the mailbox in the other.
- Is a free email marketing plan good enough?
- For opt-in sending at low volume, usually yes. Free tiers typically carry platform branding and limited automation, and the ceiling is volume rather than capability. For cold outreach, free plans are not an option at all, because those platforms prohibit the use case.
- How much should an email platform cost?
- Opt-in platforms usually price by subscriber count, so cost scales with list size. Cold outreach platforms price by sending volume or seats, typically $32 to $94 a month, but the mailboxes underneath are the larger cost and are usually billed separately.
Published 22 September 2026. Updated 22 September 2026. Written by the team that runs the infrastructure; numbers come from the platform's own provisioning and sending, and from the providers' published documentation at the time of writing.