There is an abundance of learning content and feature-rich email platforms available to marketers, yet many indie hackers make mistakes with their email campaigns that hurt future campaign deliverability. When your messages land in the spam folder, it affects the engagement rate of your campaign as well as your sender reputation, which in turn affects your future chances of landing in a subscriber’s inbox.

I’ve outlined some of the more common mistakes I’ve encountered both as an email marketing consultant for BigMailer clients and as a consumer who’s received countless emails from innumerable companies. Check out the list below and see if you can find any areas of improvement in your own marketing practices.

Mistake #1: Not creating a plain-text version of an email

You’re probably thinking “who needs a text-only version these days?” While only a tiny fraction of your audience may see the value in it, SpamAssasin is a widely used spam tool that considers it essential. The tool assigns two points to your email if no plain-text version is available. If your message reaches a score of seven, it’s identified as spam, so two points is a pretty big penalty for something that's not that hard for a savvy marketer to execute.

Some email platforms (like BigMailer that I own), auto-generate a plain-text version from the HTML version, but most platforms don't require one. If you have to create a plain-text version yourself, don’t cut corners—it should match the message in the HTML version and not be shorter. Take a look at this article from Litmus on best practices for formatting plain-text version for more guidance.

Mistake #2: Not using a preview (aka preheader) text

I cringe every time I see an email subject line followed by "view this email in a browser." Even though it isn't a visible element of your email, many platforms support specifying preheader text. If your platform doesn't support it, you can still have a preheader element as part of your email template design.

You should think of this text as a second subject line—an additional opportunity to convince your email recipients to open your email. The better your open and engagement rates are, the better chance you have of hitting the inbox in the future.

Mistake #3: Using a no-reply sender (from) address

It's not uncommon for email recipients to want to reply to messages they receive with a question or feedback. For this reason, it's best if your reply-to email address goes straight to your support team (or at least forwards to them). You don't want to discourage your subscribers from replying because replies are part of the engagement metrics that some email service providers (like Gmail) use to determine the importance of your email and whether it belongs in the inbox or spam folder.

Sometimes customers will request removal from a mailing list, and if they see [email protected], they are more likely to hit the “Spam” or “Complain” buttons instead. Complaints are the worst form of engagement you can have on your email campaigns. Furthermore, as thisGlockApps article states, "some ISPs, network spam filters, and customers' personal email security settings are set up to move messages with ‘no-reply’ addresses to the junk folder." If you care about your email campaigns' engagement rate and future deliverability, don't use a no-reply email address.

Mistake #4: Not using a descriptive sender label

It takes more than a clever subject line to stand out in a crowded inbox. Your subscribers need to recognize your startup's communication when they scan their inbox. They shouldn't be wondering why they are getting an email from some person they don't know with a cryptic subject line that promises to solve pain point XYZ.

Here are a couple of examples of senders with no startup or product mentions that I’ve received in just in the past two months:

I would suggest these three basic options for sender labels:

  1. startup or Product Name
  2. startup or Product Name + Function (e.g., Support, Sales)
  3. First Name at/from startup or Product Name

With the third option, consider the name of the person as well as your product name. Is your product name a single word, one to two words or longer? Will the entire label fit in the "From" field? Whatever format you choose, make sure to be consistent across all of your sender accounts and test before you start using the label.

Mistake #5: Using global unsubscribe from a startup

Offering subscribers a way to opt out from certain communications instead of all communications has always been under utilized by marketers, but it has become a more urgent need with introduction of General Data Protection Regulation (GDPR) laws in May 2018. According to GDPR, the consent to receive emails should be explicit and not be bundled (e.g., if subscribers only opted in to receiving product updates, you can't additionally send them promotional emails or messages on behalf of your partners).

You work hard building your email lists, so it's important to retain the subscribers on them so as not to miss out on future opportunities to engage them.

Mistake #6: Not allowing one-click unsubscribe

Some startups use a “Manage Preferences” link in the footer instead of the more expected “Unsubscribe” link. This is fine so long as it takes a user to a page where they can actually select the message types they want to receive (see the example above). However, many startups use their own built-in-house email tools, so they’ll often link that text to a page on their site that requires you to log in to your account in order to retrieve or save your preferences. This is not only a barrier to unsubscribing, which can prompt users to issue a complaint, but it’s also a practice that’s in conflict with anti-spam laws.

Mistake #7: Not validating email lists to keep bounce rate low

An average email list decays at a rate of 2% per month for B2C lists and 3% for B2B lists. The rate is higher for B2B lists because people change work emails more frequently than personal emails, due to job changes. So if you haven’t engaged with your email list for more than 3-4 months you are likely to have more than a 10% bounce rate on your first bulk campaign. A bounce rate over 10% can get your account suspended with many email service providers (ESPs), but it also has a negative impact on your email deliverability and sender reputation, not to mention cost (since you pay to send email to invalid addresses). Inbox providers pay close attention to bounce rate and may block emails from a sender that attempts to deliver to invalid email addresses.

Most email validation providers recommend that you validate your entire list once a month, or before every campaign you send, to keep your bounce rate as low as possible. While that tactic can be pricey, the good news is that most email validation providers offer great volume discounts for purchasing credits in bulk (that usually never expire). I usually recommend my customers low-cost email validation services like Bouncer (GDPR compliant, recommended for customers in Europe) and TheChecker (cheapest service there is).

Mistake #8: Not spam-testing every email

While most of the mistakes above can be corrected with routines and established practices, testing every email is an extra step that typically has to happen outside of an email marketing platform using tools provided by websites likeLitmus, Email on Acid, orGlockApps. Understandably, this step is often skipped because of the extra effort involved, but even experienced marketers using these tools can't avoid landing an email in the spam folder every once in a while. This is especially true for Gmail and is often due to the topic of the message.

If the occasional email gets a low engagement rate because a few spam keywords made it into your message, know that you are not alone. What needs to happen next is for marketing platforms to embed email testing into their platforms, to simplify email marketer's workflow. This is exactly what the team at BigMailer is currently working on, and we hope to delight our customers with this workflow improvement soon.

If you want to dig deeper into some technical implementation detail, check out this longer list of best practices to help improve email deliverability of your campaigns.

Was this article helpful? Were you able to identify improvement opportunities for your email campaigns? Please leave a comment – I would love to hear from you.

Lilia Tovbin is a co-founder of, an email marketing platform for agencies and makers powered by Amazon SES. She sold her Ed Tech B2C business in 2016 and worked as a web developer for various media companies for over 10 years before becoming a full-time entrepreneur. You can follow her journey on Twitter.