What a Newsletter Platform Can and Cannot Promise About Deliverability

Pick any newsletter platform's marketing site and you will eventually find a deliverability number. Kit's email marketing page, for example, advertises a 99.8% average delivery rate and describes it as industry-leading, alongside a claim of 40% average open rates.

Those are the vendor's own figures, published by the vendor, about the vendor. They are not audited, not independently verified, and not comparable with a competitor's number unless both are measuring the same thing — which they usually are not. This page is about what such figures actually describe, why this site publishes no deliverability ranking of its own, and where the controllable part of the problem really sits.

Delivered is not the same as read

The distinction that makes almost every advertised figure less impressive than it sounds is the one between delivery and placement.

A delivery rate measures whether the receiving mail server accepted the message. It did not bounce, the address existed, the connection succeeded. That is a real measurement and a genuinely useful one for spotting a broken list.

Inbox placement measures whether the accepted message landed somewhere a human will see it, rather than in a promotions tab, a junk folder or a filtered category. This is what people mean when they say deliverability, and it is not what a delivery rate measures.

A message can be delivered — counted as a success in any 99.8% figure — and filed straight into spam. The delivery statistic records it as a win. The reader never sees it. So a delivery rate in the high nineties is close to the industry floor rather than a distinguishing achievement: any platform whose figure was materially lower would have a list-hygiene problem rather than an infrastructure one.

Why this site publishes no deliverability ranking

There is no credible way for an independent site to rank these platforms on inbox placement, and pretending otherwise would be the most damaging thing on this page.

The measurement that gets used is a seed list: a set of addresses at the major providers, sent the same campaign, checked afterwards to see where each copy landed. It has three problems that cannot be engineered away.

• Seed accounts are not people. They have no reading history, no reply behaviour and no relationship with the sender. Filters weigh exactly those signals heavily, so seed accounts get treated differently from real subscribers.
• The result is specific to the sender. Placement depends on the sending domain's reputation, which is yours and not the platform's. A test from a clean test domain tells you nothing about what will happen from yours.
• It expires immediately. Filtering models change continuously, and a placement figure from March describes March.

Any number this site quoted would therefore be a measurement of a seed list under one set of conditions, presented as a property of a platform. It would look authoritative and mean very little, which is a worse outcome than saying so. This is the same principle that keeps every unpublished tier price off the best newsletter platforms rate card.

What the platform actually controls

None of this means the platform is irrelevant. Its contribution is real, and it is worth knowing what to ask about.

The platform provides sending infrastructure — the servers and IP addresses your mail leaves from — and it manages the reputation of those addresses. It provides authentication tooling so your sending domain can be verified. It manages bounce handling and complaint feedback loops, which is the plumbing that stops a bad list poisoning a good sender. And it enforces policies against its own worst customers, which matters more than anything else on shared infrastructure, because your mail leaves from the same place theirs does.

That last point is the strongest argument for choosing an established platform over a cheap one. You are buying a neighbourhood as much as a service.

What the platform does not control is your domain's reputation, your content, your list quality or your send frequency. Those belong to you, and collectively they decide most of the outcome.

The sender-side work that actually moves the number

This is the part that is within your reach, and it is not complicated.

1. Authenticate your sending domain. SPF, DKIM and DMARC records are the baseline identity checks receiving servers run. Every platform in this comparison provides the records; publishing them in your DNS is a one-off task and the single highest-value thing on this list.
2. Send from a domain you own. A platform subdomain ties your reputation to everyone else using it. Your own domain makes the reputation yours to build and yours to keep when you move.
3. Keep the list clean. Remove hard bounces immediately and consider removing long-term non-openers. Sending to addresses that never engage teaches filters that your mail is ignorable.
4. Make unsubscribing trivial. A reader who cannot find the unsubscribe link marks the message as spam instead, and a complaint costs you far more than a departure. On an active-subscriber meter it also costs you money, as what the meter actually counts sets out.
5. Be consistent. A steady weekly send builds a predictable pattern. Six months of silence followed by a blast to everyone is the shape of a compromised account, and filters know it.
6. Ask for replies. A reply is among the strongest positive signals an ordinary publisher can generate, and asking for one costs a sentence.

Reading vendor claims without being misled

Four questions to put to any advertised figure.

Delivered or placed? If the page says delivery rate, it is the weaker measure. If it claims inbox placement, ask how it was measured.

Measured by whom? Self-reported figures are not worthless, but they are marketing and should be read as such.

Across which senders? A platform-wide average includes thousands of accounts whose practices have nothing in common with yours. Your outcome is determined by your domain, not by the mean.

Over what period? Deliverability is a moving target. An undated figure is an undated claim.

Open-rate claims deserve a further note. Since the introduction of privacy features that pre-fetch tracking pixels on behalf of readers, open rates overstate reality by an amount nobody can quantify precisely. A quoted average open rate across a platform's entire customer base — the 40% figure mentioned above, for instance — is a number built on an inflated measurement averaged across incomparable senders. Treat it as a directional marketing claim, not a benchmark to hold your own newsletter against.

The one moment the platform choice genuinely matters

There is a single point in a newsletter's life where the platform's infrastructure is decisively important, and it is the first send after a move.

A sending domain accumulates reputation at each receiving provider over time, and that reputation is partly tied to the infrastructure the mail arrives from. Change platforms and you are presenting a familiar domain arriving from unfamiliar servers, which is exactly the pattern filters treat with suspicion. The first campaign from a new provider is the one most likely to be filtered, and it is also the one carrying your announcement that you have moved.

Warming matters here. If your list is large, sending to your most engaged segment first and expanding over subsequent sends gives the receiving providers a run of positive signals before the bulk arrives. Platforms differ in how much help they give with this, and it is a reasonable thing to ask about before committing — considerably more useful than asking what their delivery rate is. The rest of the migration sequence is in moving a newsletter list without losing half of it.

The honest position

Every serious newsletter platform delivers mail competently, and none of them can promise you the inbox, because the inbox is not theirs to give. Choose on the things that are actually verifiable — what the meter counts, where the price steps, what comes out of reader payments, and what you can take with you — and treat deliverability as a discipline you practise rather than a feature you buy.

Those verifiable things are what the best newsletter platforms rate card is built on, and they are the reason it has no deliverability column.