Email marketing: deliverability, list health, segments and the flows that earn

Email marketing works in this order: deliverability first, then list health, then segmentation, then automated lifecycle flows, and only then campaign volume. Authenticate your sending domain with SPF, DKIM and DMARC, keep the spam rate Gmail reports in Postmaster Tools below 0.3%, support one-click unsubscribe, email only people who asked, and let behaviour decide who gets what. A small clean list sending three well built flows earns more than a large bought list sending a weekly newsletter, because every number in email is downstream of whether the message arrives at all.

This page covers deliverability, list health, segmentation, lifecycle flows and the metrics worth reporting. For picking a specific platform, run a trial against the flows listed here.

Deliverability: the floor everything else stands on

Mailbox providers publish their requirements, so this part is a checklist rather than a mystery. Google's email sender guidelines require every sender to Gmail personal accounts to set up SPF or DKIM, have valid forward and reverse DNS records for sending domains or IPs, use a TLS connection, keep spam rates reported in Postmaster Tools below 0.3%, and format messages to RFC 5322. Senders of more than 5,000 messages a day to Gmail accounts need SPF and DKIM together, DMARC on the sending domain, the From header domain aligned with the SPF or DKIM domain, and support for one-click unsubscribe plus a clearly visible unsubscribe link in the body. Google also notes that sending to personal Gmail accounts requires a DKIM key of 1024 bits or longer, and recommends 2048.

• Set up Postmaster Tools on day one. It is the only place you see the spam rate Gmail is measuring you by. Treat a rising line as an emergency before a block arrives.
• Start DMARC at p=none, read the reports, then tighten. Moving to quarantine or reject before you know every legitimate sender is how payroll emails vanish.
• Send from a subdomain. Marketing from news.example.com keeps reputation separate from the domain your invoices leave on.
• Warm a new sending domain gradually. Begin with your most engaged recipients and raise volume over weeks.
• Read the other providers too. Yahoo's sender best practices cover the same ground for its mailboxes, and most of the advice overlaps.
• Follow the law where your recipients are. The FTC's CAN-SPAM compliance guide covers US commercial email, and consent based rules apply in the EU, UK, Canada and India.

List health

A list is an asset that decays. The job is to keep the engaged part growing faster than the dead part accumulates.

• Collect with permission and a clear promise. State what you will send and roughly how often, right at the form.
• Use confirmed opt-in where quality matters more than speed. It costs you signups and buys you a list that engages.
• Validate at the point of capture. Catch typos and role addresses before they become bounces.
• Run a sunset policy. If somebody has not opened or clicked in a defined window, move them to a low frequency stream, then stop. Inactive recipients drag your reputation down for everybody else.
• Keep suppression permanent. Unsubscribes, hard bounces and complaints never come back, including in an imported file.
• Never buy or scrape a list. It fails the consent rules, it spikes complaints, and the reputation damage lands on the domain you need for everything else.

Segmentation that pays for itself

Most lists need five or six segments, not fifty. Build them from behaviour and recency rather than demographics, because behaviour predicts the next action.

Segment	Built from	What to send
New and unconverted	Signed up, no purchase or enquiry yet	Welcome sequence, proof, one clear offer
Engaged, not bought	Opens and clicks, no order	Objection handling, comparison, trial or sample
Recent customers	Bought in the last period	Onboarding, how to get the most from it, review request
Repeat customers	Two or more orders	Early access, bundles, referral ask
Lapsing	Past the typical repurchase gap	Reminder, what has changed, incentive last
Cold	No engagement in the sunset window	One honest re-permission email, then suppress

The lifecycle flows to build, in order

Automated flows earn more per send than campaigns because they arrive when the person is interested. Build them in this order and stop when the next one stops paying.

Flow	Trigger	The job
Welcome	Signup confirmed	Deliver the promise, set expectations, make the first ask
Abandoned cart or form	Started, did not finish	Remove the one thing that stopped them
Browse or quote follow up	Viewed a category or requested a price	Answer the obvious next question
Post purchase onboarding	Order or contract confirmed	Get them to the result, reduce support load
Review and referral	A set period after delivery	Collect proof, ask for an introduction
Win back	Past the repurchase gap	One reason to return, incentive only at the end

Write each flow as a sequence of two to four emails with a stop condition, so somebody who converts drops out immediately. A flow that keeps selling after the sale is the fastest route to a complaint.

The metrics worth reporting

Open rate has become a soft number since mail privacy features began loading images on the recipient's behalf, so use it as a directional signal and judge on clicks and money.

• Delivery rate and bounce rate, split into hard and soft. This is your list hygiene score.
• Spam complaint rate, read in Postmaster Tools as well as your platform.
• Click rate and click to open, which tell you whether the subject promise matched the content.
• Conversion rate per send, measured against the action the email asked for.
• Revenue or pipeline per recipient, the only metric that makes a small engaged list look as valuable as it is.
• List growth net of unsubscribes and suppressions, reported as one number.

ESP, automation platform, or CRM?

Three categories of tool send marketing email and they suit different businesses.

• Email service providers such as Mailchimp, Klaviyo, Campaign Monitor and Brevo focus on sending, templates, segments and flows, and integrate with your store or site. Strongest where email is the main channel and ecommerce data drives the segments.
• Marketing automation platforms such as HubSpot Marketing Hub, ActiveCampaign and Marketo Engage add scoring, multi step branching, landing pages and deeper reporting across channels. Strongest for longer considered sales with a sales team attached.
• CRMs with email built in, including Zoho, Salesforce and Dynamics, keep one record per person across sales and marketing. Strongest where the sales conversation matters more than the campaign.

Pricing in all three categories is tiered by contacts, sends or seats and changes often, so compare on each vendor's own pricing page rather than on a figure from an article. Whatever you choose, confirm three things in the trial: that it authenticates your own sending domain, that flows support a stop condition, and that you can export your list and your templates on the way out.

Asked and answered: email marketing

How often should I email my list?

As often as you have something worth opening, and at the frequency you promised at signup. Let the data decide: raise frequency for the engaged segment, lower it for the rest, and watch complaints and unsubscribes rather than open rate.

Why did my emails suddenly start going to spam?

Check in this order: authentication records changed or expired, spam rate in Postmaster Tools, a recent import of old or bought addresses, a jump in volume, and content that triggers filters such as a single image with no text. Nine times in ten it is the import or the volume jump.

Is a double opt-in worth the lost signups?

Yes when deliverability is fragile, you have a new sending domain, or your signup form attracts bots. Single opt-in with validation and a strict sunset policy also works. Pick one and run it consistently.

What is a good open rate?

Compare yourself against your own last six months, by segment, rather than against a published benchmark. Mail privacy features have made the absolute number less comparable across senders, so your own trend on clicks and revenue per recipient is the number to manage.

Do I need a separate CRM if my email tool has lists?

You need a CRM when a human follows up individually and needs to see the history. If email is your only touch, a good email platform is enough. The moment sales people are involved, one record per person in a CRM saves more time than it costs.

Where your audience is already asking

Your list consists of people who chose to hear from you. Many of the people you want next are asking an assistant instead of joining anything: who should I use for this, and is it worth the price.

Your flows can help, since the emails and pages you send to subscribers are often the clearest statement of what you do. Compare your welcome email with what an assistant says about you; any gap shows where your message is lost. AI Knows Us asks the main assistants and reports which pages shaped each answer.