Email Deliverability: Best Practices and Mistakes to Avoid in 2025

Email deliverability isn’t rocket science. 

However, it takes some specific knowledge to make sure every email you send gets through to the recipient. If you’re looking to maximize your delivery rate, you will either need to go through some trial and error and figure it all out on your own or seek professional advice from the experts. 

To make it easier for you, we’ve asked 11 experts to weigh in on three questions:

• how to fix email deliverability when Google is killing open rate
• common mistakes that might harm your sender reputation and
• email deliverability best practices to follow in 2025 to prevent that.
  

Here’s what they had to say about deliverability in email marketing and cold outreach.

Google is killing open rates

Email deliverability is the heart of any cold email campaign.

It’s not just about crafting the perfect message or personalizing each outreach; if your emails never make it to the inbox, everything else falls flat. One of the biggest email deliverability issues we’re facing right now is Google’s recent update, which impacts how open tracking works. This shift is shaking up the game for cold email marketers everywhere, making it more difficult to monitor how well your emails are performing.

So how do we navigate these changes? What steps can we take to ensure our messages still land in the inbox? Here’s a vital insight from a recent webinar on cold email deliverability that tackles this head-on:

“Google killed open tracking… Whenever you track openings, Google will show some notifications with the call to action to report as spam. So your spam rate will go up, and this is a really bad thing. It’s better not to track cold emails’ openings rather than track them because of this new update. Open tracking has never been a completely accurate metric, but before, it was a good way to detect when your deliverability went down. Now, without it, you lose that signal, so you won’t know exactly when your deliverability is dropping.”

To solve this, ‘turn off your open tracking as soon as possible… remove images from your emails.‘ You can still ‘enable link tracking‘ as an alternative, and ‘switch to plain text mode only,‘ which removes all HTML and can drastically ‘improve your deliverability.‘ Focus on reply rates instead of open rates to track engagement and avoid spam warnings from Google.

This advice is crucial for anyone relying on cold emails for outreach.

The key takeaway here is to shift your focus from open rates to reply rates, eliminate unnecessary tracking, and embrace simpler, more direct email formats like plain text. This approach helps bypass spam filters and ensures your message gets where it needs to be—without triggering Google’s new anti-spam measures.

Want to dive deeper and see the full conversation, with even more actionable tips? Check out the full webinar below, where experts share insights from analyzing over 50 million emails:

Take the time to watch this—trust me, it’s worth it. You’ll walk away with practical strategies you can start using immediately to improve your deliverability and drive more meaningful engagement with your cold email campaigns!

Also, grab our Cold Email Deliverability Playbook—get expert advice, tools, and benchmarks to optimize your cold email campaigns and turn them into opportunities, all in one free guide.

What are the 3 common mistakes that might harm your domain reputation?

Damien Brenelière

Co-Founder & CEO of MailReach, email deliverability software designed to maximize the inbox rate of cold emailing campaigns. Damien managed the cold emailing campaigns and deliverability of 130 companies in 40+ industries and used cold emailing to generate 56M in funding for seed rounds and IPOs

LinkedIn 

According to me, the 3 common mistakes that might harm your domain reputation are:

1. Sending too many cold emails per day per domain. A good domain reputation is the result of human and well balanced email activity. According to us at MailReach, the maximum should be 200 cold emails per day per domain.
2. Not including an easy-to-spot unsubscribe link. Today, having your emails marked as spam is much more harmful to your domain reputation. Not having an easy-to-find unsubscribe link will mathematically result in a higher number of spam complaints which leads to a bad domain reputation over time.
3. Spending too little time on cleaning and removing the non-targeted people from your list and especially by filtering on the job titles. If your email is designed to target CEOs and you target people who are not CEOs, your email will not be targeted and that will result in a higher number of spam complaints. Spend time on removing the wrong people, and correcting first name and last name inversions to avoid the “Hey Last Name” and so on. Mistakes and bad targeting hurt your domain reputation by pissing off people who’ll mark your email as spam.

Alec Beglarian

Founder of Engage.Guru, Inc. and EmailMastery.org. Alec helps businesses and startups set up the right foundation and architecture for email that can scale – as well as selling more with email by building relationships with their subscribers & making sure emails get delivered into the inbox. 

LinkedIn | Twitter

Email deliverability and reputation rests on 2 pillars, namely technical infrastructure and engagement.

The technical setup of your email delivery services should be a one-time matter to ensure domain and IP authentication align. Engagement is ongoing best practice for deliverability email marketing and targeting is the main objective here to avoid harming the domain reputation.

1. The first common mistake I see email marketers make is tracking and making decisions based on open rate but not paying attention to open reach — while open rate will tell you how many subscribers open each email, open reach will tell you how many unique subscribers open any email over a given period of time, which is a far better metric for measuring subscriber engagement.
2. The second mistake is tracking subscriber engagement too generally. Most businesses are getting subscribers from a lot of different sources — lead magnets, free trials, ads on various platforms, influencer campaigns, etc. — but they don’t track the performance of their email campaigns (open rate, open reach, click-through rate) based on traffic source. Different sources will provide varying levels of subscriber quality. It’s important to keep an eye on which sources provide high-quality subscribers and which are giving you duds.
3. The final mistake is focusing too heavily on list size or send size and too little on subscriber engagement. Better engagement can mean better deliverability, more sales, and a thriving business… even if it’s from a smaller list than your competitors. After all, a 15% open rate on an email list of 10,000 is the same result as an open rate of 30% on an email list of 5,000 — so I’d suggest email marketers spend more time thinking about the quality of their list, their subscribers, and their emails… and less time thinking about the size.

Scott Hardigree

Founder and CEO of Email Industries, a leading email deliverability services agency and the company behind list hygiene solutions, AlfredKnows and BlackBox.

LinkedIn | Twitter

Mistakes are made under pressure or when under-resourced. That’s why I chose these typical scenarios that our clients find themselves in. Avoiding them might eat into our bottom line so revealing them may not be in my best interests, but they are in the best interests of your deliverability.

1. Poor list maintenance and hygiene. There are all manner of reasons why you may have historically not kept proper records: You may have migrated systems or platforms and lost user open and click history. That is no excuse, however, to keep hitting dead or dormant accounts. Take a holistic and ongoing approach to your list hygiene and regularly ensure your recipients’ addresses are indeed truly active and use an email list hygiene service like AlfredKnows before you start to see long-term deliverability issues.
2. Erratic sending. For whatever reason, you believe you absolutely must send that message to all users ever, ever, ever and it has to go out right, right now. You are very likely wrong. No matter the scenario, I have not experienced a situation where a more targeted, planned, and structured approach will not yield better results. Even under pressure, take the time to think it through or you will find yourself under potentially greater pressure for even longer.
3. Not being properly authenticated. I know it’s all technical and geeky, involves DNS records, and a bunch of techie mumbo jumbo, but it is essential to get this done and get it right these days, folks. Sure, if you are sending smaller amounts of email you can find yourself successful. But if you ramp those efforts up, your deliverability will not scale the way you want it to. Unless you follow best practices about sending emails of value, you will need to be properly authenticated.

Michal Leszczynski

Head of Content Marketing & Partnerships at GetResponse, a comprehensive marketing automation platform. Michal is a content marketing expert who’s just as eager to lead the team as to get his own hands dirty by creating SEO-optimized and data-backed content that generates sales leads and organic traffic.

LinkedIn | Twitter

1. Emailing stale lists. Emailing old and inactive email lists is rarely a good idea. While it may be tempting – who would say no to an extra sale? – it usually leads to low engagement levels, spam complaints, and unhappy customers. Solution? Take it slow; target your older contacts along with your most-engaged subscribers to see if they respond. If it works – you can gradually include more of these contacts in your campaigns. And if it doesn’t? Consider reconfirming your contacts or setting up a re-engagement campaign.
2. Lack of segmentation. Email blasts are the most popular type of campaigns email marketers run to this day – and who’d blame them? They’re all too easy to set up. But while they can work from time to time, they shouldn’t be the core of your email marketing strategy. In 2025, if you want to maintain high deliverability and email ROI, you’ll want to shift toward more targeted campaigns. And if you’re worried about extra work, start with the easiest ones like welcome emails, basic follow-up sequences, and cart abandonment emails. Just set them up once, and you’ll soon see they generate at least 2x more engagement than your standard emails.
3. Too frequent communication. Marketers often don’t plan to flood their audience with too many emails, yet it still happens. Why? Often, it’s because they’re trying to set up too many campaigns – newsletters, autoresponders, behavior-triggered sequences – all at the same time, without thoroughly thinking them through. As a result, the same contact could receive multiple emails sent within a short amount of time, just because they signed up for your ebook, newsletter, or visited your pricing page. The solution? Carefully think through and test your workflows. Look out for a platform that lets you move people between the sequences or limit the maximum number of messages they can receive within 24 hours.

Adrian Williams

Founder of Email Angels – Email Delivery & Inboxing Experts. Spanning a career of over 25 years, Adrian has worked with many notable technology, e-commerce, and lifestyle brands as an Email Marketing Specialist.

LinkedIn

1. If you’re not sending the right message to the right user at the right time, you can very quickly get low engagement on your email campaigns which in turn can put your emails into the spam folder. (Use your baseline metrics to figure out fluctuations in engagements). If you don’t react quickly when you see your engagement dip, sending reputation can take a major hit really fast, and it might take weeks to recover from the damage that was done.
2. Another common mistake is not sending enough emails! Believe it or not, some of your recipients will forget about you if you seldom send them emails and they’re more likely to hit the spam button. Simply because they forgot who you are! Rule of thumb is to send at least 1 email a week. It must be something of value from the recipient’s point of view. 
3. If you send B2B, it’s extremely beneficial to use active seeds. This is a complete game changer and almost a necessity in today’s competitive environment. Hands down the best seed system on the market is InboxAlly.

Invest greatly in your email program, it will deliver great dividends. Email is the LONG game, be patient!

Oleksii Ianchuk

Product Manager at Mailtrap, an email testing & transactional email sending service. Oleksii has been working with different products for the last 7 years. Today he helps to build Mailtrap Transactional Email Sending that focuses on preventing issues with deliverability and offers the best service. 

LinkedIn

1. Not monitoring your reputation and metrics. You should do that constantly. That’s why Mailtrap offers weekly and daily alerts so you can be aware in advance if something goes wrong.
2. Sending marketing campaigns using transactional email sender. That’s possible, but you have to know how to do that. It’s always better to talk with the service you use as they advise you on the best way to do that.
3. Sending to users what they don’t expect to get from you. Make sure your users are happy and opted in to receive content from you and you respect their unsubscriptions and complaints.

What are the 3 best practices for email outreach to ensure high deliverability in 2025?

Brian Minick

Chief Operating Officer at ZeroBounce, email validation service and deliverability toolkit. With 15 years of experience in Operations, Brian ensures that you get the most out of ZeroBounce. His goal is to make email work for your business – and together with his team, he’s helping more than 150,000 customers land in the inbox.

LinkedIn

Email deliverability is complex, but it shouldn’t be a mystery. Someone who follows noreply email best practices and uses common-sense when sending emails should be able to land in the inbox.

Here are the top 3 email deliverability best practices senders should use as a guide:

1. Take great care of your email list. It’s your no. 1 asset, so grow it yourself and keep a close eye on how it evolves. Your metrics tell you a lot. Bounces are a definite sign you need to remove outdated contacts. Do it right away, because when your bounce rate exceeds 2%, you’re at risk of landing in Spam. Ask for permission to send emails and also, use double opt-in. Never email again someone who’s marked you as spam. As for disengaged subscribers, decide whether you want to reengage them with an offer or remove them from your list. Either way, you shouldn’t ignore them for more than three months.
2. Send content people want and expect. Taking your subscribers by surprise is not a good way to boost your deliverability. When they sign up for your emails, people expect the content you promised, so do your best to deliver on that promise. Otherwise, you could see a high number of unsubscribes and spam complaints, which is bound to direct you to Spam. Moreover, make use of the data you’ve gathered about your customers and prospects. It’ll help you segment your list and create content for specific groups. Lastly, think of what spammers do – and do the opposite. Avoid all caps, excessive exclamation points, spammy words, or too little text in ratio to your images.
3. Send your emails like clockwork. Ideally, on the same days and at the same times. This supports your inbox placement in several ways. First, sending emails regularly keeps your IP warm. Also, you build familiarity with your list. People will become accustomed to seeing you in their inboxes, so they’ll be more likely to engage. Familiarity boosts your brand awareness, too. So, while you’re helping your click rate, showing up consistently keeps your business top of mind.

Andrew Bonar

Founder of emailexpert and Executive Advisor (Deliverability) at Bonjoro. Andrew Bonar has been working in email for over 25 years, part of the founding team @Pobox in the UK. He now works as an executive advisor for companies across the email and messaging space including Halon based in Sweden, Bonjoro in Australia and Emailexpert in the UK while organizing international industry events including Inbox Expo, Deliverability Summit, and Festival of Email.

LinkedIn | Twitter

I will preface by saying I have always believed deliverability is more than just reaching inbox, it is about your email message being received and seen by your recipients when and how you expected it to be. So that means not just inbox, but timely inbox placement and then of course for that message to render as expected. The best practices for deliverability have not changed all that much over time; however, implementing those same rules may take even greater effort in 2025.

1. Send email that your users are expecting and/or will be grateful to receive. With an ever-crowded inbox this gets harder and even with permission overzealous marketers could find their messages marked as spam. Aspects such as good list hygiene, good segmentation, targeting, and action-led messaging all have a part to play here.
2. Authenticate your email and monitor your mail flows. In 2025 it is becoming ever more important to get all the technical details of authentication right and many mailbox providers have raised the bar even higher in 2025. SPF, DKIM, DMARC have long helped with consistent delivery for high-volume mailers. This year you will increasingly hear that DKIM alignment is now a minimum prerequisite for reliable delivery.
3. Ensure you’re accessible as email is increasingly being opened and viewed on all manner of devices and ways. Whether the user is on a desktop, mobile, tablet or using a screen-reader, your messages need to be accessible to the recipient. If the subscriber cannot “read” your message once it was delivered, then it may as well have been filtered to junk. Poor accessibility, formatting, and rendering can lead to problems with filters, unsatisfied recipients, and can drive unsubscribes and spam complaints.

Trevor Hatfield

Managing partner of the Inturact Capital Fund. A private equity fund that acquires, grows and exits B2B SaaS companies and Head of Product at SendX which is a 360-degree email marketing automation platform for B2B companies. SendX helps companies acquire and engage customers at scale.

LinkedIn | Twitter

1. Clean up your list. Cleaning up your email list means removing any invalid, inactive, spam traps, or catch-all email addresses. Cleaning your list helps improve email deliverability in two ways. First, you won’t be marked as spam too often when you remove inactive emails and send emails to people who actually want to receive/read them. Secondly, it will improve your engagement rates (open rate, click rate). Email senders with high rates of opens and clicks are considered more trustworthy by email security filters. These data points are used by inbox providers to determine whether to send you to a spam folder or inbox.
2. Don’t send image-only emails. Email clients can only parse text. They do that to detect spammers, unsavoury content or fraudulent behaviour. That’s why spammers will send image only content to try to pass the filters and reach people’s inboxes. When you show the same behaviour as a spammer, your emails would be blocked as a defence against spam. If you wish to make your emails look beautiful, on-brand and drive conversions use email templates – these are pre-made emails that you can customize to suit your branding and put your text. Try the ever-expanding template library offered by SendX.
3. Follow Content Best Practices. Your email content is as important for the inbox providers as it is for the recipients. If an inbox provider considers your content to have spam-like qualities such as – attachments, the subject line in CAPs, links that point to unsecure websites, and grammatical errors – then your email delivery is much more unlikely as the message has higher chances of going to the spam folder. So proofread your emails, avoid shortening your links when you hyperlink a text, button, or image, and link only to genuine sites with reputable domains.

Yanna-Torry Aspraki

Deliverability Specialist & the CBDO of EmailConsul. Sitting on the executive team at the intersection of Product, Growth, and Sales, YT helps drive the company forward in a market in desperate need of accessible and reliable email deliverability tools, while representing EmailConsul in places email & deliverability have never been before.

LinkedIn

1. Make sure you are sending to people who specifically signed up for your emails. Inbox service providers and spam filters are able to easily detect if you are purchasing lists and will penalize you for it. Engagement with your emails is crucial, so remember that it is important to not overwhelm (bombard) your clients with basic, useless emails. Always try to get feedback from them or simply ask subscribers what they want to receive and find valuable. In case they are not active and are ignoring your emails for some period, like 3 months, delete them from your system.
2. Use a simple subscription process, but be clear with how subscriber’s emails will be used. Value should be explained clearly on your form and you should notify prospective subscribers at which frequency you will be communicating with them. Don’t forget about double opt-in and reCAPTCHA as they will help protect your signup forms and reduce bounces, spam complaints, and form abuse that will affect your domain reputation and deliverability.
3. Monitor your domain reputation and deliverability closely. You have a different relationship, reputation, and inboxing rate with every single inbox provider you send emails to (Gmail, Yahoo, GMX, etc.). You can start with a simple email seedlisting test. The process is simple: You are provided with a list of email addresses you can send your email to, which will then give you a report of which emails landed in the inbox, spam folder, or were never received at all. You can also monitor DNSBL listings, which will inform you when they are on blocklists! This allows you to mitigate issues quickly before sending your next campaign.

Remember, most inboxes do not provide the information on who clicked on “this is spam.” Meaning that you might have high spam complaints, but you don’t know it because the inboxes you are sending emails to don’t provide this information. Gmail/GSuite is the most notable inbox that does not provide this information. 

If Google doesn’t provide this information, your email marketing service providers, such as Mailchimp or Netcore Cloud, also cannot tell you who is reporting your emails as spam.

Matthew Vernhout

VP Deliverability at Netcore Cloud. Matthew is a digital marketing and privacy advocate, the chairperson of the ANA’s Email Experience Council, director at large with the Coalition Against Unsolicited Commercial Email (CAUCE), Communications Chair with the AuthIndicators Working Group (BIMIGroup), founder of the Canadian Email Summit (emailsummit.ca), co-founder of GradeMyEmail.co. He is a trusted industry expert, recognized as the 2019 EEC thought-leader of the year, and is a Certified International Privacy Professional (Canada) (CIPP/C). Matthew speaks frequently at email marketing and technology conferences around the globe, and maintains his celebrated blog, EmailKarma.net.

LinkedIn | Twitter

Email deliverability is driven by a number of factors including data collection, authentication, engagement, technical configuration, and feedback provided by consumers. To ensure that you have good email deliverability you need to take all of these elements into consideration when building and maintaining your email program. 

1. Start by taking a look at your data collection practices. Are you gathering the right consent when collecting email addresses to send them messages? In a recent case study, opt-in data delivered 21 times better conversion rates than non-opt-in emails. This shows that users who request information from a brand are significantly more likely to engage and positively respond to their content.
2. Authenticated email should also be on a brand’s radar when they are looking at sending emails and getting good delivery. Implementing SPF, DKIM, and DMARC with fully aligned domains (envelope and friendly from using the same domain) will improve the confidence that messages are actually delivered from your domain. These solutions work together to prevent brand spoofing and phishing, which has been shown to improve email delivery speeds and increase consumer trust in a brand. Which in turn leads to more engagement and indicates to the mailbox provider that these messages are worth delivering to the recipient’s inbox.
3. Finally, look at building more engaging emails with AMP for email. Adding interactive elements to an email like a product flip book, a survey, or tools to book meetings and follow-ups directly from the inbox makes it more convenient for consumers to interact with your messages.

Building strong practices around consent, engagement, and user satisfaction has been a path to deliverability success for several years. Layering on new technologies around authentication, interaction, and branding will bring your email program a new more engaging experience to your subscribers.

Damon Sauer

Director of Deliverability at Sendlane, an all-in-one eCommerce marketing automation tool. Email Marketing and Deliverability Manager (SME) with advanced knowledge of SMTP systems, SaaS Development, Operations, and Custom Programming Solutions, Damon is an industry recognized leader in the email field, backed up by 25+ years of direct experience.

LinkedIn

1. Create and send engaging, impactful, and premium content to affirmatively signaled, organically collected contacts.
2. Manage the lifecycle of every email/client/customer in your mailing lists and remove those that are or have disengaged in a timely manner.
3. Smartly segment and provide a cadence that doesn’t overwhelm your client/customer – test, test, TEST!

Wrapping up

So, the experts have spoken. As you can see, most of them agree on the key aspects of email best practices at work:

• High email deliverability starts with proper technical setup and authentication.
• Having a clean and targeted list is crucial for email marketers and outreachers alike.
• Maintain a consistent sending schedule and watch the limits to avoid any deliverability issues.
• Keep an eye on your sender reputation — track the key metrics, test it regularly (there are paid as well as free email delivery services you can use), and adopt practices like email warm-up to fix any issues that may arise.
• Email content and engagement are the two factors that can make or break your deliverability email efforts in the long run.