Vladislav Podolyako
Feb 08, 2022
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These days, when email marketing has become an integral part of any lead generation strategy, a robust ESP takes a key role in configuring any company’s MarTech tools. The best email service providers offer more than a domain and an email account. They protect your sender identity and provide you with improved functionality that marketers and SDRs appreciate for cold email outreach.

Can popular email service providers ensure that your email deliverability rates will only get better? Some may have partner deliverability programs and offer spam tests while other tools don’t. On the Belkins Growth Podcast S2E4, Michael Maximoff discusses the nuances of most used email clients with Mike Hillyer, Founder & CEO of Email Ninjas, an online education solution for email management.

For those who are still learning the ropes on how different email services work, Mike explains the difference between paid and free email service providers and the criteria to choose the best business email service providers.

What should you look for in business email service providers (ESPs)?

Unlike average consumers who send a handful of emails throughout the day, B2B companies typically have a significant sending volume and require special features to manage their cold outreach campaigns. If your sending frequency is low, free plans from consumer email giants like Gmail or Outlook will protect your inbox from spam and offer enough customization. For all other cases, make sure your ESP choice ranks well on each of the criteria from the list.

  • Security. The way ESPs interpret security may sometimes differ from what users expect of them. For example, Gmail, Yahoo, and Microsoft don’t use end-to-end encryption, and Google is notorious for scanning emails for keywords to show users personalized inbox ads. In Outlook, encrypted messages are read and replied similarly to unencrypted messages, while third-party encryption applications may use decryption. Hence, if security is your priority, look for alternatives on the market that have strong security protocols and other security features like end-to-end encryption, two-factor authentication, etc. However, virus protection and spam filtering are a priority for most. At the very least, spam filters sort out spam messages into spam folders and automatically delete them after 30 days.
  • Use of AI. Artificial Intelligence is widely used in technology, improving systems and UX/UI. Mike says, “Many ESPs are starting to use AI as a way of doing spam filtering. Gmail, in particular, is very strong in these practices these days.” And one of the things that they do with that is they look at thousands of data points to determine whether your message has something in common with either a desirable or an undesirable message and act accordingly. Also, ESPs that use AI offer bifurcation of emails, auto-reply detection, canned responses, and text prediction while writing emails.
  • Customization. From a custom email address to the layout of your inbox, your ESP of choice must be flexible enough to make your user experience effective and pleasurable. For example, Zoho, Gmail, and Microsoft allow users to use their business’s name for their email addresses. So, you will get at the end of your email address rather than It looks more professional. As for the inbox layout, sorting and organizing your messages into folders is essential when choosing among the top email service providers.
  • Mobile-friendly. The best business email service providers seem to be mobile-friendly. Just in case, make sure the service of your choice will not have trouble showing your emails on smartphones and other gadgets. Neither should the screen size be a problem nor the functionality of your service’s mobile version.
  • Support. In B2B email marketing, customer support is one of the critical factors in favor of the service. Marketing and sales teams are fast workers with large message volumes. If something goes wrong, they need to know that the vendor will do its best to help with their request, question, or complaint. Look for a provider with a strong support team at your beck and call for help and information. Especially if you’re choosing among free email service providers, check not only email, phone, and live chat support but also uptime of service (for how long the provider has been in operation). If you operate across different countries, multilanguage support is essential.
  • Ease of use. Email marketers and SDRs engaged in email outreach need a wide range of functions that must be easy to use. There’s a learning curve when starting to use an enterprise-level complex software tool (that’s why you need a friendly and knowledgeable support department). But overall, installation and user experience should be easy.
  • File size. Some email marketing campaigns or online business interactions may require large-size files. While most free email service providers normally don’t offer more than 15 to 25 MB in free plans, Global Mail Exchange is known for attachment sizes up to 50 MB. Consider using a third-party file sharing tool if an email client of your choice has file size limits, even in paid plans.
  • Integrations. The best business email service providers boast add-ons, tools, and integrations to improve their basic email products. When services discover users’ needs, they arrange multiple app integrations with other vendors: sales enablement, productivity, lead scoring, and whatnot. Customers choose according to their needs. For example, many ESPs have integrations with spam testing tools and test your draft emails for spam before sending.
  • Scalability. This is a tricky criterion. On the one hand, it’s wise to foresee your future email needs that will come up when your business grows. On the other hand, scalability that requires automation can be disruptive for cold email marketing. Mike explains, “I’m a founder of a company. I know exactly how an automated outreach email looks like.” And email service giants like Gmail or Microsoft don’t appreciate their clients having too heavy traffic as it automatically means bulk messaging and spam. The best way to use a tool like Outreach or Gmail is personalization and research. Doing so slows the process down enough that the tools aren’t detecting automation. They’re looking at it as a one-to-one email.

The best business email service providers

Gmail, Outlook, Yahoo, and Microsoft are consumer giants that offer multi-functional email clients. However, if cold email outreach is your primary marketing strategy, using third-party tools like SparkPosts, SendGrid, PepePost, or MailGun is a better choice to prevent your messages from getting into spam and bouncing back.

Mike explains, “It’s not a good idea to use GSuite for anything other than corporate mail as it can take down your domain reputation, and Google will eventually.” When Google and the gang see too much marketing traffic that gets complaints, you can wind up losing your corporate email capabilities because you use your corporate email stack for your marketing email. That’s why MailChimp, SendGrid, and others may be better suited for email marketing at scale.

With that being said, let’s take a closer look at each service and its offerings.

Google Workspace

In its basic free version, Google’s Gmail has every feature that a happy customer is thankful for: streamlined interface, dynamic mail, filtering with customized folders, spam blocking, virus protection, and powerful search. Gmail and other Google services (Google Photo & Drive) share 15GB of email storage. Gmail attachment limit is 25 MB, although Google Drive can store files larger than 25 MB so that the body of your email message sends a download link to the file. A Gmail account supports multiple Gmail addresses, with a custom business email address, if needed. You can also check emails from other accounts in Gmail. The mobile app has limited functionality but viewing and searching features are solid.

Gmail for business is a paid tool that is part of Google Workspace (formerly GSuite) that includes Google Docs, Sheets, Forms, Slides, Drive, Calendar, Hangouts Chat, Hangouts Meet, and many more. With pricing starting at $6 per user/month, you get 24/7 customer support and 99.9% uptime on all plans. Each paid plan gives more storage, support, and access to applications. Unlimited storage space starts at the Enterprise Plan (pricing is available by request), plus more advanced security, data loss prevention, and admin features. A 14-day free trial is available.

  • Pros. A web-based search engine by keywords, attachments, and other criteria; multiple email accounts, collaboration, popularity (so it’s easier to onboard team members and freelancers), smart email compose, and email scheduling
  • Cons. Sponsored ads in free accounts, no bulk clean-up, no multiple email signatures, requires third-party tools

Microsoft Outlook / Microsoft Office 365

Outlook is an email client from Microsoft that offers an easy-to-navigate intuitive interface with advanced message filtering, free storage space, and an integrated calendar. Users can view and edit attachments in Outlook internally, either as links or copies. Outlook Mobile gives a view of Focused Inbox (without notifying about Other messages) and supports advanced search. Use customizable swipe gestures to delete, flag, mark as read, or archive messages. Free storage capacity is 15 GB per Outlook account and 5 GB of free cloud storage per Microsoft 365 account.

Offering Outlook for free for personal use, Outlook Premium is available for Microsoft 365 subscribers. With prices starting at $5 per month per user, the upgraded Office 365 offers users an ad-free inbox, custom email addresses, 50GB mail storage, 1TB of cloud storage space, standard security, 99.9% uptime, and 24/7 phone and web support. Outlook Business Premium at $20 per month per user (paid annually) also includes cyber threat protection, file recovery from cyber attacks, email encryption, access and data control, advanced security, plus the latest versions of the full Office applications and cloud services. Users can try any paid plan for one month for free.

  • Pros. Many tools and apps, collaboration tools, advanced search, and email scheduling
  • Cons. Poor compatibility with third-party integrations and tools

Yahoo! Mail

As well as a popular search engine, Yahoo is also a free email sender. Powered by Artificial Intelligence, Yahoo Mail’s sorting capacities are not as granular as Gmail’s. However, its ability to find documents, videos, and images in the Sent or Received emails is impressive. Not allowing for attachments larger than 25MB, Yahoo Mail provides a whopping 1 TB of free storage on free accounts and impressive spam filters. Yahoo allows users to create up to 500 disposable email accounts for personal use without offering encryption. The Yahoo Mail app is almost identical to the Gmail app, and virus protection is on par with Gmail and Outlook. As of January 1, 2021, Yahoo made email forwarding a paid feature available in a Pro Plan ($3.49/month) or as an add-on service ($12), but users can share files from Google Drive or Dropbox.

With a Yahoo Mail Pro plan starting at $41.88 per year, paid plans expand the range of features, including a custom domain, contact import, productivity tools, priority customer support, and an ability to view all your inboxes on the same screen. In paid plans, it is possible to import contacts from social media.

  • Pros. 1TB of free inbox storage, disposable email addresses, strong spam filters, advanced search
  • Cons. Sponsored ads in free accounts, a paid forwarding service


As a marketing giant, HubSpot offers free email hosting and email marketing software. HubSpot email client enables users to create personalized emails by customizing the layout and adding CTAs and images. In addition to an easy-to-use drag-and-drop editor, HubSpot offers detailed analytics and reporting, A/B testing, and email health score.

Users can upgrade to HubSpot marketing automation software and get more features. At $45 per month (paid monthly), HubSpot Starter increases limits on free marketing tools, gives faster email and in-app chat support, and removes branding from HubSpot forms and landing pages. Collaboration tools and omnichannel marketing automation become available starting from the Professional Plan at $800 per month. The Enterprise Plan costs $3,200 per month and includes 10,000 marketing contacts, adding behavioral event triggers, reporting, predictive lead scoring, and much more.

  • Pros. Professionally-looking email designs, drag-and-drop editor, auto-create tasks, detailed engagement analytics
  • Cons. More expensive because of its email marketing software in comparison to other providers on the market


Suitable for small businesses, Zoho Mail can easily migrate data from your previous email service provider and connect to the other Zoho tools. In terms of security, Zoho Mail provides biometric authentication, password manager, end-to-end encryption, 2FA, and spam protection. Zoho’s authentication includes Touch ID, QR code, and OTP. A mobile version is available along with a web application and can be used on other third-party email providers.

Zoho’s free version offers 5GB inbox storage, a 25 MB attachment limit, and a mobile app and web access for up to 5 users for a single domain. For $0.90 per month, attachment size increases up to 250 MB and for $3.60 up to 1GB, plus 50 GB inbox storage space per user. All paid plans offer multiple domain hosting, email routing, email access, collaboration tools, offline access, the apps and other IMAP/POP clients, and white-labeling. Start with a 15-day free trial.

  • Pros. The free plan allows up to 5 users, deleting and archiving email in bulk, ad-free inbox
  • Cons. No contacts import from social media


Rightfully considered the most secure web-based email client, ProtonMail’s privacy and encryption solutions include a strict no-logs policy, address verification, full support for PGP email encryption, and elliptic curve cryptography. ProtonMail’s mobile app is available for both Android and iOS.

The free version offers limited support, 500 MB of storage, 150 messages per day, and no smart filtering or organizational labels. Paying €5 per month gets you 5GB storage, 5 email addresses, 1,000 messages per day, up to 200 folders, and one custom domain for one user, plus filtering and autoresponder options. At €8 per month, you get an unlimited message allowance, multi-user support, and multiple folders and labels. The €30 Visionary Plan comes with 20GB storage, 50 email addresses, and up to 10 custom domains.

ProtonMail provides under 25MB attachment size and no cloud storage for all plans. It makes the use of third-party cloud storage and other apps inevitable.

  • Pros. High-end security, custom domains
  • Cons. Too pricey for an email client


Although many know MailChimp primarily as an email newsletter tool, it is an email service provider that allows its clients to create and send messages and improve email deliverability. MailChimp has a partner program for deliverability with limited functionality. The free plan allows up to 2,000 subscribers, up to 12,000 emails per month (2,000 per day), and access to guides and tutorials for customer support. There’s unlimited storage data and images, but each file cannot be more than 10MB in size. A/B testing and 24/7 support are available in paid plans. The most affordable one starts at $11 per month based on 500 contacts.

  • Pros. Spam- and design-testing, bounce management, all the multi-channel tools
  • Cons. No own domain in pro plans, expensive subscription plans


SendInBlue is an all-in-one marketing platform that enables users to send emails and SMS, create landing pages and forms, and integrate with CRMs. From a drag-and-drop editor to A/B testing and detailed reporting, SendInBlue offers the whole package for email campaign management, including email list building, email templates, and contact management.

Unlike many other top email service providers who charge based on the number of contacts stored, SendInBlue’s pricing is based on the number of emails sent. The free plan includes 300 emails per day, and the $25 plan has advanced statistics, email support, and no daily sending limit. A $65 plan grants multi-user access and telephone support. Any advanced needs are possible in the Enterprise Plan for a quote.

  • Pros. Support in 6 languages, an intuitive drag-and-drop email builder, email personalization features, unlimited lists and contacts
  • Cons. Pricey

Tools to improve email deliverability

If you hate your deliverability rates, it’s not a reason to change your business email service provider. As Mike remarks, “Changing ESPs because you don’t like your deliverability rates is as crazy as changing a gym because you want to lose more weight.”

Deliverability has very little to do with which ESP you use. Some do have certain tools that help you improve your deliverability if you use them correctly. But the reality is that deliverability has so much more to do with what you are sending and who you’re sending it to than what service you are using to send it.

Leaving copywriting tips and lead generation tricks for the next time, let’s look at email spam maintenance and email performance monitoring tools.


This AI-based platform is a versatile email deliverability tool that shows superb results in increasing your open email rate, CTR, and reply rate. From warming up your mailboxes to running email spam tests, Folderly skillfully mimics human-to-human behaviors and helps with inbound and outbound email marketing.

You can choose between two Folderly packages: Spam Fix (an all-in-one solution to prevent email-related issues and maintain high deliverability) and Warmup Package (unlimited email testing, blacklists, spam words checker, monitoring, warm-up, etc.).

Cold Email Outreach (B2B) – $160/month for one mailbox

Inbound Email Marketing (B2C) – $8,000/month for 1-3 million emails

Let’s sum up

If you’re just starting up and want to choose from the best free email service providers, look at Gmail, Outlook, Yahoo, Zoho, Sendinblue, and ProtonMail.

ProtonMail is the most secure email client on the list (while also you can consider Tutanota, Hushmail, and CounterMail). Gmail is universally considered the gold standard among email services. Yahoo has the strongest anti-spam protection. Outlook offers the widest list of app integrations. Zoho Mail is the best option for small teams.

Simultaneously, the combination of an excellent webmail service (Gmail, Outlook, etc.) and a specialist tool (ProtonMail, etc.) can be an optimal decision for many. Compose your messages in the ESP of your choice and use a tool that will take care of all of the delivery and is not attached to your corporate mail. Then you’re not worried that GSuite (Outlook, Yahoo, etc.) is going to cut you out entirely so that you can’t even send your business mail. Always use a separate service for email outreach.

Vladislav Podolyako
Vladislav Podolyako
Founder & CEO
Vlad’s decades of entrepreneurial wisdom and business building experience have allowed him to successfully mentor a diverse group of business owners, entrepreneurs in growing their companies. A recognized expert in the areas of transforming organizational culture and leadership development, B2B Sales, Marketing, spent more than 10 years building technology products, with a background in communication networks and electronic device engineering.

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