by Albright Labs
Every deliverability conversation eventually reaches the copy. What is the subject line, how is the opener written, is the ask clear.
The copy matters. It matters considerably less than the list.
A well-written email to a badly prepared list will damage your domain. A plainly written email to a clean, relevant list will not. List work is the least interesting part of sending email and the part that decides the most, which is roughly the definition of work that gets skipped. That is as true of a newsletter list you have collected for years as it is of a customer or member list you imported last week.
Bounce Rate Is a Reputation Metric
A bounce is a signal to the receiving provider that you do not know who you are mailing.
Legitimate senders mail people who exist. Someone working from a stale or purchased list does not, and the bounce rate makes the difference visible immediately. Providers treat sustained high bounce rates as evidence of exactly that, and the reputation damage attaches to your domain, not to the campaign. Sending services act on it too: Amazon SES reviews an account at a 5% bounce rate.
Verify every list before it goes out, using a verification service, and remove everything that comes back undeliverable. Then hold yourself to a threshold and enforce it. We stop at three percent. If a campaign crosses it, we pause rather than throttle, because past that point every additional send is spending reputation that every future campaign depends on.
The instinct when a campaign is underway is to push through and fix the list next time. That instinct is the expensive one.
Catch-All Addresses Need Diluting
A catch-all domain accepts mail to any address, whether or not the mailbox exists. Verification services cannot confirm those addresses, so they come back neither valid nor invalid.
They are unverified rather than useless, which is a different problem. Some are real people and some are not, and you will not know until you send.
The practical answer is proportion. Keep catch-all addresses to a modest share of any given campaign, well under a third, so that the ones which turn out to be dead are diluted by addresses you have confirmed. Do not build a campaign predominantly out of them, and do not use them at all while a domain is young and has no reputation to absorb the misses.
Remove Generic Addresses
info@, contact@, office@, admin@. These arrive through contact forms, old imports and shared signups, and they look harmless. They are not.
A generic address usually forwards to several people, none of whom signed up and none of whom expected your email. That is a bad ratio for replies and a worse one for complaints, because you have multiplied the number of people who might reach for the spam button by a single send.
Send to the individual who asked. If a shared inbox is the only address you have, confirm that someone there actually wants your email before keeping it on the list.
Fix the Errors That Read as Carelessness
Contact data arrives dirty. Two problems recur often enough to be worth checking for specifically.
Name inversions: first and last names swapped, so the greeting reads “Hi Doe” instead of “Hi John.” The recipient does not conclude that your data was messy. They conclude they received a mail merge, and mail merges get reported.
Job title artifacts: titles like “PA to CEO” land in a segment meant for chief executives and are not the CEO. The email arrives addressed to someone who cannot act on it and knows immediately that you did not check.
Both are cheap to find and cheap to correct. Both cost you a reply and risk a complaint if you do not.
Relevance Is a Deliverability Control
The most reliable way to avoid spam complaints is to email people who might plausibly want the email.
This is advice about reputation, not reply rates. Complaints are one of the fastest ways to damage a sending domain, and the lines are thin: Google tells senders to keep their spam rate below 0.1% and never reach 0.3%. The people most likely to report you are the ones the message had nothing to do with.
So the question before every send is how many of the people on the list still want this particular email. Cutting a send from four thousand to twelve hundred by leaving out people who have not opened or clicked anything in a year reduces the number of people positioned to damage your domain.
Trim aggressively. The people you left out were not going to read it.
Do Not Buy Lists
Purchased lists fail in a specific and predictable way.
You cannot assess the quality, the addresses are frequently stale, and, most importantly, the list was almost certainly sold to other buyers before you. The people on it are being contacted constantly by everyone else who bought it. They are primed to report the next cold email they receive, and yours is the next cold email they receive.
There is a second problem. Many sending services forbid them outright. Amazon SES prohibits sending to purchased or rented lists, and Postmark allows only permission-based lists. If you send through one of those, a bought list puts the account itself at risk.
Build your list from people who asked to be on it. It is slower and it is the only version of this that works.
Where the Addresses Should Come From
The most reliable source is the people themselves: a signup form, a checkout opt-in, a membership application, an event registration. The data is maintained by the people it describes, which is a property no purchased database has, and a confirmation step proves the address works before any campaign goes to it.
Whatever the source, the same rule applies at the end: verify before sending, and old imports most of all. A good source reduces how much cleanup you have to do. It does not remove the step.
A Sequence That Works
The order matters, because each step reduces the cost of the next.
- Collect from people who asked, rather than buying addresses.
- Cut for relevance first, before spending money on verification for contacts you will not mail.
- Correct the data errors, name inversions and title artifacts.
- Remove generic addresses.
- Verify what remains and remove everything undeliverable.
- Check the catch-all proportion and dilute if it is high.
Then send, and watch the bounce rate on the first batch before committing the rest.
Final Thoughts
List work has no visible output. Nobody reviews a cleaned list the way they review a subject line, and there is no moment where it feels finished.
It is still where the outcome is decided. The email you send to the wrong person at a stale address takes something with it, and it takes it from every campaign you plan to run afterward.
Sendly’s email validation handles part of this before you send. It flags bad syntax, domains with no mail server, disposable addresses, role-based addresses such as info@ and support@, and duplicates, and lets you remove them in bulk. It does not check whether a mailbox exists, so it is a first pass rather than a replacement for a verification service. Sendly also sends only to subscribers who have confirmed their address, so an address that was never confirmed never receives a campaign.