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Best SMTP Service Providers for Fast & Reliable Email Delivery

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Before starting a new website or a venture that relies on email marketing and smooth user communication, you might want to educate yourself about Simple Mail Transfer Protocol (SMTP) services.

Because of how complex SMTP is, many CMS platforms don’t offer any email deliverability service.

Instead, they leave you to rely on yourself and integrate a third-party SMTP server that can send emails to customers.

Doing so is essential, considering how it makes communication with your target audience much easier.

Over the decades, many SMTP service providers popped up with optimistic promises.

But which one is the best for your needs?

That’s what we’ll discuss in this post, so stick around!

Why Do I Need an SMTP Service Provider?

SMTP, or Simple Mail Transfer Protocol, is the standard protocol for sending emails, thanks to its authentication methods that lead to high deliverability rates.

An SMTP relay service often seems unnecessary for personal or recreational use.

But if you’re running a business, it’ll help you communicate with your customers reliably.

It’ll also let you set marketing and transactional emails to send upon detecting specific triggers.

For example, it can send verification emails to users’ inboxes when they register or receipt emails when they make a purchase.

So if your web host provider doesn’t come with an SMTP service, you’ll have to explore some apps that can fulfill that purpose.

The 5 Best SMTP Service Providers in 2023

SMTP isn’t a new service.

In fact, it predates the internet itself by one year.

The market has given enough time to developers to create the best service providers with excellent deliverability rates.

So thankfully, we’re spoiled for choice here.

Here are more details on our picks for the best SMTP service providers.

1. SMTP.com – Best Overall Pick

smtp homepage screenshot 1

SMTP.com is one of the most popular SMTP services in the market, servicing over 100,000 businesses worldwide.

What makes SMTP.com stand out as an efficient SMTP relay service is its ability to send bulk emails at a fast delivery speed.

This makes it a favorite among high-volume senders since you can send emails, and your audience will receive them almost instantly.

You can also set custom triggers through SMTP.com’s main API so that the server will send an email depending on customer behavior on your platform.

For example, you can rapidly send a massive batch of registration emails, transactional emails, authentication emails, and more, all of which are the type that can’t handle any significant delay.

SMTP.com also offers an email API that makes it easy to integrate other websites and applications into the SMTP server.

For example, it’s famously easy to integrate on a WordPress website through the WP Mail SMTP plugin.

And you don’t need to worry about data security as this service sends emails securely using SSL encryption.

SMTP.com boasts advanced deliverability features, such as the Reputation Defender add-on that maintains your email list health by ensuring email delivery and protecting your emails from ISP bans.

You even get some neat feedback on how users interacted with your email, such as click-through rates, open rates, unsubscription rates, etc.

However, the data presentation lacks detail, in our opinion.

Unfortunately, there’s no free plan or even a free trial to let you test out the service before committing.

However, the paid plans are reasonably priced and scale well as your business or website grows.

Key Takeaways

  • A popular platform for bulk SMTP sending
  • Quick delivery rates
  • Reputation Defender add-on that increases reliability
  • Customer behavior data available
  • One of the best SMTP email services for large businesses
  • Highly scalable


  • Essential: $25/month, up to 50,000 emails per month
  • Starters: $80/month, up to 100,000 emails per month
  • Growth: $300/month, up to 500,000 emails per month
  • Business: $500/month, up to 1,000,000 emails per month
  • High Volume: Custom quote, 2,500,000 emails or more per month

2. Postmark – Best for Fast Email delivery

postmarkapp homepage screenshot 1

Postmark is a Software-as-a-Service SMTP email service that offers email deliverability at high speeds and is easy to integrate with other marketing channels.

It’s easy to set up transactional emails with Postmark while keeping your sender reputation sound to avoid having your emails flagged as spam.

On top of that, with this service, your clients will receive the transactional email you’re sending nearly instantaneously, which improves your image if you tend to send emails that contain time-sensitive information like payment confirmations or delivery updates.

There are two types of SMTP servers that Postmark offers: shared and dedicated.

Low and medium-volume senders get their emails sent through a shared IP.

This can save you the hassle of setting up your own server and having your SMTP email-sending services there.

However, it’s slightly slower than dedicated servers, especially during high-traffic times.

On the other hand, high-volume senders (those who send 300,000 emails or more per month) get a dedicated IP, which is the fastest you can go.

You can also pick from automated or manual email warm-ups, though we recommend the first option for most people.

In either case, high-speed delivery is Postmark’s main selling point, and they don’t compromise that regardless of your subscription plan.

We also fell in love with Postmark’s email analytics tools, which display bounce rates, open rates, click-through rates, and more.

And they retain data for 45 days for all their plans, so you’ll get ample time to analyze your results.

Key Takeaways

  • SaaS SMTP service focused on high-speed delivery
  • Shared and dedicated IP servers (depending on your email volume)
  • Detailed email analytics are available
  • 45 days of data retention
  • Easy to integrate with other apps
  • Free trial available


  • Up to 10,000 emails per month: $10/month
  • Up to 50,000 emails per month: $50/month
  • Up to 125,000 emails per month: $100/month
  • Up to 300,000 emails per month: $200/month
  • Up to 700,000 emails per month: $400/month
  • Up to 1,500,000 emails per month: $700/month
  • Up to 3,000,000 emails per month: $900/month
  • Up to 5,000,000 emails per month: $1,200/month
  • More than 5,000,000 emails per month: Custom quote

3. Sendinblue – Most Comprehensive Tool

screenshot of the sendinblue homepage

Sendinblue is a tool that started as an email marketing service aimed at small to medium-sized businesses, but it later transformed into a more comprehensive and powerful marketing platform.

Sendinblue has no limit on how many contacts you can add to your email list.

And it comes with some valuable segmentation tools that allow you to send emails of different natures to the user group you choose.

For example, you can segment your contacts by their engagement levels and benefit from their high activity to market your most recent product.

Or, you can segment by device and send shorter emails with larger buttons to users on a mobile device.

And if you want to branch your marketing strategy outside of emails, you can do so with Sendinblue by launching SMS marketing campaigns through the app, which allows you to schedule texts to your users.

Oh, and you can utilize segmentation here too.

As for email delivery speed, it doesn’t lag behind its competitors, thanks to its reliable SMTP servers, which can handle bulk emails and are constantly well-maintained to avoid noticeable delays.

There’s also a team of email delivery experts who strive to ensure maximum deliverability rates so that your marketing emails can reach everywhere.

And unlike the two other options above, Sendinblue offers a free tier! It only allows up to 300 emails a day, but it’s great for testing out the app before making the final purchase.

And we’re not even mentioning the plethora of other marketing features within the CRM hub, which can complement your email campaigns nicely.

Admittedly, though, these features may be redundant if you only need an SMTP service provider.

Key Takeaways

  • Full-blown marketing hub
  • Reliable SMTP service with reliable delivery speed
  • Works well for small and medium-sized businesses
  • Other tools available, such as SMS marketing and segmentation
  • Free plan available (300 emails per day)


Sendinblue doesn’t have a fixed set of paid plans.

Instead, you get one free plan and three paid plans with various features and dynamic prices based on your monthly email-sending capacity.

  • Free: $0/month, up to 300 emails per day
  • Lite: Starts at $25/month, up to 20,000 emails per month
  • Premium: Starts at $65/month, up to 20,000 emails per month
  • Enterprise: Custom quote, more than 1,000,000 emails per month

4. SparkPost – Best for Large Businesses

sparkpost homepage screenshot 1

SparkPost is a premium SMTP service that specializes in sending transactional and marketing emails with a focus on tight email security, reliable deliverability, and valuable analytics.

That’s why it’s favored by some tech giants like LinkedIn, Pinterest, and Zillow.

SparkPost uses more than 35 metrics to measure email list health, including bounce, click-through, and open rates, engagement and acceptance reports, and more.

These extensive analytics can help you identify problem areas in your strategy.

This way, you can strengthen your campaign performance.

As for reach, SparkPost uses its signature AI-backed Adaptive Delivery technology.

It analyzes current delivery data from different ISPs and markets to optimize your email for them and minimize blocks or delays due to technical hitches.

SparkPost knows what it’s like to struggle with email, especially among big corporations that can’t afford to lose due to technicalities.

That’s why they also provide a dedicated technical account manager (or TAM, as they call them) who studies your business and its SMTP implementation.

Unfortunately, you only get a TAM if you subscribe to a Premier and Enterprise plan (the two highest-paid plans), so it automatically rules out any small business and most medium-sized ones.

Still, if you’re running a big business, you can benefit from the TAM’s on-demand support and dedication.

The TAM also works with other developers and staff in the email team at SparkPost to remain up-to-date with trends and methods.

Key Takeaways

  • One of the best SMTP email services for large businesses
  • In-depth analytics with over 35 metrics to analyze health
  • Dedicated technical account manager with Premier and Enterprise plans
  • Fast delivery rates


SparkPost doesn’t have fixed paid plans.

Instead, it depends on how many emails you need to send every month.

There’s also a free SMTP service.

  • Test: $0/month, up to 15,000 emails per month
  • Starter: Starts at $20/month, up to 50,000 emails per month
  • Premier: Starts at $75/month, up to 100,000 emails per month
  • Enterprise: Custom quote, more than 5,000,000 emails per month

5. Mailgun – Best for Developers

mailgun homepage screenshot 1

Many SMTP providers are actually full-fledged email marketing hubs or even more comprehensive marketing hubs.

While this might be a bonus point for some, it’s overkill if you’re only looking for an SMTP relay service.

Enter Mailgun, one of the more straightforward SMTP email services on this list, as it caters to developers who are comfortable using email APIs to send emails en masse.

This grants the user a decent amount of flexibility with their setup and integrations.

Mailgun is also relatively easy to integrate on a WordPress site, thanks to the WP Mail SMTP add-on on the WordPress plugin market.

On top of that, Mailgun is a transactional email tool that allows you to send automated trigger-based emails, analyze customer behavior through useful data metrics, and see what actions visitors take on your website.

All of this is done through the service’s email API, so you’ll need a bit of technical background here.

As for data security, you won’t have to worry about it when using Mailgun, as it doesn’t track you or share data with any third parties.

Plus, all the data is stored in highly secure, far-away servers.

Another neat feature is the burst-sending feature, which allows you to schedule many emails to send at different times.

This is ideal if your audience is based around different time zones.

Key Takeaways

  • Developer-focused SMTP provider
  • Easy to integrate on a WordPress site using WP Mail SMTP
  • Can be integrated on other platforms (requires code knowledge)
  • Highly secure—no privacy concerns
  • Burst-sending feature


Mailgun doesn’t use fixed prices for its plans, instead relying on its clients to purchase a dynamically-priced plan that fits their monthly capacity.

There’s also a free one-month trial with a decent capacity for testing.

After that, here are the starting prices and limits of the paid plans.

  • Trial: $0/month, up to 5,000 emails per month, limited to one month
  • Foundation: Starts at $35/month, up to 50,000 emails per month
  • Growth: Starts at $80/month, up to 100,000 emails per month
  • Scale: Starts at $90/month, up to 100,000 emails per month
  • Enterprise: Custom quote, more than 2,500,000 emails per month

How to Pick the Best SMTP Service Provider for Your Needs

A flourishing market for any service is always a bonus.

But to an outsider looking in, especially if they’re new to the service, it can be overwhelming trying to find the most optimal choice.

So we’ve highlighted the main factors you should consider before picking an SMTP email service.

1. Email Deliverability

Email deliverability is the main selling point here.

After all, the reason to choose an SMTP service provider is that you want to ensure your emails are successfully delivered.

So before picking a service, research its deliverability rates and see if there are reports or complaints about email delivery.

Depending on your industry, you might also need emails to deliver quickly, so check how fast the SMTP server is and see if it works for your needs.

2. Ease of Use

Setting up an SMTP service is one of those procedures you don’t think about when starting a website.

And to be fair, it’s a rather complicated field.

That’s why you should consider how easy or difficult it is to implement the service on your website.

  • Is it straightforward? Will you need to maintain it frequently?
  • Can you set it up once and forget about it?

Another important point is the available support.

Can you expect to reach customer support reliably and have them solve your problem in a reasonable time frame?

Will you have to pay extra, or do you get some help as part of your subscription plan?

3. Email Analytics

Customer data is crucial for the success of many businesses.

So you’ll want to check if the SMTP service can track useful behavior-related metrics to provide insight into user behavior.

This can also help you figure out what’s working and what’s not.

And in turn, you can experiment with new delivery methods to ensure your customers are satisfied.

The Bottom Line

That’ll be it for our review of the five best SMTP service providers.

Luckily, it’s a booming market with tools to suit everyone’s needs.

Our favorite tool is SMTP.com, but yours might differ, so we picked a diverse set of services.

For instance, if you’re a small or medium-sized business, check out Sendinblue, which was originally an email marketing tool for this business size.

In contrast, large businesses can benefit from SparkPost, which caters to huge tech clients and offers assistance in the form of technical account managers.

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