The Spam Filter Checklist: 15 Words and Formatting Habits That Get Creator Emails Blocked

You've done everything right. You built a clean list of people who actually asked for your emails. You send consistently. And yet your open rate just quietly dropped from 38% to 19% over three sends, with no obvious cause. Before you blame your list or your subject lines, look at the body of the email itself — because inbox filters read your words and your formatting, not just your reputation. A perfectly healthy list can still get throttled into spam folders by a message that reads like a 2009 promo blast: ALL CAPS SUBJECT, six exclamation points, the word "free" three times in two sentences, and a wall of hyperlinks with almost no plain text around them. This is a separate, fixable lever from sender reputation, and most creators have never actually audited it.

Why content-level filtering exists (and why it still matters in 2026)

Early spam filters were almost entirely keyword-based — block "viagra," block "free money," done. Modern filters at Gmail, Outlook, and Yahoo are far more sophisticated, weighing sender reputation, engagement history, and authentication (SPF/DKIM/DMARC) far more heavily than any single word. But content scoring never went away — it's just one signal among many now, and it's the signal you have direct, immediate control over. A borderline sender reputation plus a spammy-looking email is often what tips a message into the junk folder, when either one alone might have been fine. Think of it as stacking risk: your list quality is one pile, your formatting habits are a second pile, and filters look at the combined height.

This is genuinely useful news if you're running a small creator broadcast, because content is the pile you can fix in the next ten minutes, versus list health, which takes months to rebuild. If you're sending campaigns through your store.fan storefront's built-in tools, this article is the fastest deliverability win available to you today.

The 15 highest-risk words and phrases

None of these words are an instant death sentence in isolation — filters weigh combinations and context, not a single blocklist match. But creators consistently underestimate how often these cluster together in a single promotional email, especially around launches and flash sales. Here's the list worth scanning your drafts against before you hit send.

Formatting habits that hurt you as much as word choice

Word choice gets all the attention, but formatting is arguably the bigger lever, because it's structural and filters can measure it precisely. Four patterns show up in almost every creator email that lands in spam.

1. ALL CAPS anything

A subject line or body sentence in all caps reads as shouting to both humans and filters. "SALE ENDS TONIGHT" scores worse than "Sale ends tonight" even though the words are identical. Reserve caps for a single short word at most, and never the whole subject line.

2. Image-to-text imbalance

One of the oldest spam techniques was sending an email that's just one big image with no real text, because keyword filters couldn't read images. Filters caught on decades ago and now specifically penalize image-heavy, text-light emails — the exact pattern a single giant promo banner creates. If your email is one graphic and a button, add at least 100-150 words of real, readable body copy around it. This also happens to make better marketing sense: people buy from words that explain the offer, not just a flashy banner.

3. Link-to-text ratio

Count your links against your word count. An email with 8 hyperlinks and 40 words of surrounding text is a textbook spam pattern — it reads as a link farm, not a message from a person. A healthy ratio is roughly one link per 100-150 words, with one clear primary call to action rather than five competing buttons pointing at five different products.

4. No plain-text alternative or broken personalization tags

If your email tool only sends HTML with no plain-text fallback, or if a merge tag fails and the email literally goes out reading "Hi {{first_name}}," that's a strong spam signal — it looks exactly like a broken mass-mail template. Always send a test to yourself first and actually read it before it reaches your list.

If it reads like an infomercial, it scores like one.— the shortest version of this whole article

Where this fits with everything else in your deliverability stack

Content formatting is one piece of a bigger picture that also includes authenticated sending domains, list hygiene, and consistent send cadence — but it's the piece you can fix today, for free, with a five-minute re-read. If you're new to sending broadcasts at all, it's worth building the habit from day one rather than retrofitting it later. Every store.fan storefront comes with built-in campaign tools designed for creators specifically, so you're not stitching together a separate email platform on top of your storefront — your customer list, your discount codes, and your broadcast emails all live in one place. If you haven't set that up yet, you can create your store and start sending to your customer list in the same afternoon.

It's also worth remembering why this matters beyond open rates: every email that lands in spam is a missed chance to turn a follower into a sale. A flash-sale announcement that never gets seen doesn't just fail quietly — it costs you real revenue on a day you were counting on. Clean, human-sounding copy isn't just a deliverability trick, it's also just better marketing; the emails that avoid spam triggers tend to read better and convert better too, because they sound like a person talking to another person instead of a template shouting at a list.

The takeaway

Spam filtering isn't a mystery box — it's a scoring system, and content is the part of that score you control completely, every single send. Run the checklist above before your next campaign, and you'll fix the majority of formatting-level risk in the time it takes to read your draft once out loud. Curious what a well-built storefront and campaign setup actually looks like end to end? Check out a live example store, browse more guides on email and storefront strategy, or compare plans to see what's included at each tier.