Best deliverability practices

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Why Deliverability Matters

If your email lands in spam, it doesn’t matter how good it is, nobody will see it. Deliverability is about making sure your newsletters end up in the inbox, where your readers can open, click, and engage.

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1. Engagement Is Everything

Mailbox providers (like Gmail, Outlook, Yahoo) decide whether to trust you based on how subscribers interact with your emails.

• Good signals: opens, clicks, replies, moving your email to “Primary” or out of spam.
• Bad signals: ignoring your emails, deleting without opening, marking as spam.

Your job is simple: send content people actually want and encourage them to interact. You can do this adding Surveys, asking your subscribers about what they want you to write about, or many other things. Get creative!

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2. Send to the Right People

Your list health is the foundation of deliverability.

• Only email people who opted in: never use purchased or scraped lists. If people don’t expect an email from you and they mark you as spam, it will affect all other users, even the ones that want to receive your emails!
• Target engaged subscribers first: focus on readers who open and click, answer your emails or vote your polls and surveys.
• Clean inactive subscribers: if someone hasn’t opened in months, stop sending to them.

A small but active list is always more valuable than a massive one full of inactive subscribers. A smart move is to upload your list and segment it, keeping your most engaged readers in a separate group and start sending them your first emails.

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3. Tips to land in the Inbox

What you write matters. Spam filters scan your content before readers ever see it.

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A. Be Human, Not Spammy

Avoid shouting (“FREE!!!”), all caps, and too many exclamation marks. These are classic spam triggers and instantly make your message look untrustworthy. Instead, write like you’re talking to a friend over coffee. Keep your tone natural, clear, and conversational. Think about how you’d write an email to one person, not to a faceless crowd. That means:

• Use plain, simple language that’s easy to read.
• Be specific instead of vague: “Get your free productivity guide” works better than “LIMITED OFFER!!!”.
• Show your personality: don’t be afraid to sound like yourself. We all love to hear about the human behind the newsletter!

The more your emails sound like a real person, the more likely they are to be trusted by mailbox providers and opened by your readers.

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B. Subject Lines That Work

Your subject line is the first impression your email makes and often the only thing that decides whether it gets opened or ignored. A good subject line balances clarity, curiosity, and trust.

• Keep them short: Aim for 6–10 words. Most inboxes cut off long subject lines, especially on mobile, so get to the point fast.
• Be clear, not clickbait: Over-promising or tricking readers will only increase spam complaints. Instead, tell them exactly what they’ll get inside.
• Curiosity beats hype: Pique interest without exaggeration. Compare: “3 ways to simplify your week” feels inviting, while “You won’t believe this!!!” screams spam.
• Test variations: Small tweaks in wording can make a big difference. Try testing subject lines to see what resonates most with your audience.
• Add a personal touch: If it makes sense, include details relevant to your readers. Even subtle personalization can lift open rates. Do you have a local newsletter? Be sure to mention the city!

Think of your subject line as a headline in a newspaper: short, compelling, and promising enough value that readers want to dive into the story.

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C. Balance Text and Links

The way your email is structured matters as much as the words you use. Spam filters look closely at the ratio of text to links and images, and so do your readers.

• Limit your links: A handful of relevant links is fine, but cramming every line with clickable text or buttons looks suspicious.
• Focus on one main action: A good rule of thumb is that each email should drive the reader toward a single clear outcome. Instead of a dozen scattered links, include one relevant call-to-action (CTA) that matches the purpose of that email.
• Always include real text: Avoid sending emails that are just a giant image or graphic. Many inboxes block images by default, which means your email could look completely blank. A healthy mix of text and visuals makes your content more accessible and trustworthy.
• Keep formatting clean: Overly complex layouts, broken HTML, or hidden links can set off spam filters. Simple, readable structure usually works best.

Think of links and CTAs as your spotlight: pick one thing to highlight, make it obvious, and let everything else support that single action.

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D. Be Predictable

Both email providers and your readers reward consistency. If you tell subscribers you’ll send once a week, and then you actually show up once a week, your open rates will almost always improve.

• Set clear expectations: Let people know how often they’ll hear from you when they sign up: daily, weekly, or monthly.
• Stick to your schedule: ESPs (like Gmail and Outlook) track patterns. Sudden bursts after long silence look suspicious, while steady rhythms build trust.
• Train your audience: When readers know your newsletter always arrives on Tuesdays at 9am, they’re more likely to look out for it (and open it!)
• Avoid ghosting: Going quiet for months and then blasting your entire list usually leads to higher spam complaints and lower engagement.

Predictability isn’t boring, it’s professional. Over time, your consistency becomes part of your brand, and both inboxes and readers will treat you as a trusted sender.

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4. Keep an Eye on Your Metrics

Your numbers tell the real story of your deliverability. They show how mailbox providers see you and how much your audience actually cares about what you send. Tracking them regularly helps you spot problems early and make the right adjustments.

• Opens: A steady or growing open rate means people are interested and mailbox providers trust you. Sudden drops can signal issues, maybe your subject lines aren’t connecting, or worse, your emails are slipping into spam.
• Clicks: Click-throughs reveal whether your content resonates. If opens are high but clicks are low, people are curious enough to open but not motivated to act. Time to refine your calls-to-action or relevance.
• Spam complaints: This is the killer metric. Keep complaints as close to zero as possible (definitely under 0.1%). Even a few “Mark as Spam” clicks tell providers that your content isn’t welcome, and they’ll start filtering you aggressively.
• Unsubscribes: Don’t panic if some people leave. A clean list is better than an inflated one. Unsubscribes are healthier than spam complaints, they show readers opted out the right way.

If engagement drops: tighten your list by removing inactive subscribers, sharpen your subject lines, and double down on delivering content people actually want. Think of metrics as your inbox compass. They don’t just measure success, they guide you toward better deliverability every time you hit send.

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5. Common Mistakes to Avoid

Even with good intentions, many senders fall into traps that hurt deliverability. Here are the big ones to watch out for:

• Emailing people who never signed up
  Sending to purchased lists, scraped addresses, or random contacts is a guaranteed way to get flagged. These people don’t know you, so they’re more likely to mark you as spam. Always stick to permission-based email.
• Overloading with links and images
  A message crammed with links, buttons, or one big image looks like spam to both filters and readers. Balance visuals with text, and keep links purposeful.
• Using misleading subject lines
  “Your invoice is ready” when you’re actually sending a newsletter? That trick might get opens once, but it destroys trust and trust is what inbox placement depends on.
• Ignoring inactive subscribers
  Continuing to blast people who never open your emails drags down engagement rates, which makes providers assume nobody wants your content. Clean your list instead of chasing ghost subscribers.
• Sending inconsistently
  Vanishing for months and then sending a huge blast will almost always trigger spam filters. Consistency builds trust; randomness looks suspicious.
• Treating your list like a megaphone
  Email isn’t just a one-way street. If all you do is shout at your audience without encouraging interaction, your deliverability will suffer. Invite replies, ask questions, and make it feel like a conversation.