Choose the Best Transactional and Marketing Email SMTP Provider

Email continues to be the most reliable method for business operations and marketing outreach. However, running an email system takes a lot of time and effort, plus it poses risks when you lack proper professional knowledge.

Partnering with an SMTP provider, you can let them handle email delivery and focus on building quality content. Yet, the number of SMTP email solutions available makes it hard to find the one best suited for your requirements.

We compared the top 8 contenders across key criteria like deliverability, reliability, pricing, features, and ease of use. In this guide, you’ll find:

• An overview table comparing the top picks’ prices
• Methodology for choosing an SMTP provider
• Detailed reviews of each best SMTP service provider
• Our advice on choosing the best SMTP service for email marketing

Whether you’re a developer sending transactional emails or a marketer managing campaigns at scale, use this guide to choose the ideal SMTP solution.

Top Picks Summary

Here are our top recommendations if you need an SMTP service focused specifically on:

• Reliable deliverability: Mailtrap, UniOne
• Marketing features: SendGrid, Mailjet
• Easy API integration: Mailgun, Amazon SES
• Mailchimp extension: Mailchimp Transactional
• Budget constraints: Amazon SES

See the price comparison table below for an overview, with full reviews in the next sections.

SMTP Provider Price Comparison Table

Provider	Free Plan	Pricing
Mailtrap	1,000 emails/month	Starts at $15/month for 10,000 emails
UniOne	6,000 emails/month	Starts at $6/month for 10,000 emails
SendGrid	3,000 emails/day	Starts at $15/month for 15,000 emails
Mailgun	6,000 emails/month	Starts at $15/month for 10,000 emails
Mailchimp Transactional	1,000 emails/month	$12.30/month for 5,000 emails plus regular fee
Amazon SES	3,000 emails/month for 12 months	Pay-as-you-go, $0.10 per 1,000 emails sent plus regular fee
Mailjet	6,000 emails/month	Starts at $17/month for 15,000 emails
Postmark	100 emails/month	Starts at $15/month for 10,000 emails

*Pricing valid as of January 2025

Choosing an SMTP Provider: Methodology

When comparing SMTP providers, we evaluated them across four key criteria:

Email Infrastructure

This part includes fundamental delivery tools such as servers setup, performance tracking systems, special IP addresses plus expansion options. A solid infrastructure system makes email delivery effective and stable.

Pricing

We search for pricing options that fit all email senders regardless of their volume. Tiers that let you grow your business are preferred.

Customer Support & User Experience

The provider should give you several ways to get help plus clear instructions for starting your project. User interfaces that follow the way people think make products easier to use.

Features

The email service features you need depend on the work you perform. The best SMTP services designed for marketing needs should have built-in list management and campaign automation tools, while transactional email success depends on API quality.

Let’s explore each SMTP provider in detail across these criteria.

Mailtrap – One of the Best Smtp Services

Mailtrap focuses on helping developers and marketers test, send, and track transactional and marketing emails with reliable deliverability.

This provider offers more outgoing messages for free while scoring over 93 percent successful email placements and monitoring your full email setup.

Key Stats

• 93.2% inbox placement rate
• Deliverability testing tools
• Free tier with up to 1,000 emails/month

Plan	Monthly Cost	Emails/Month
Free	$0	1,000
Starter	$15	10,000
Business	$49	50,000
Enterprise	Custom	500,000+

Pros

• Excellent deliverability and inbox placement
• Generous free plan
• Easy integration and detailed analytics
• Testing tools to prevent missends
• Responsive customer support

Cons

• Limited marketing automation features
• Higher cost for large volumes

Mailtrap provides users with the most advantageous combination of essential tools and services. Unless you need advanced marketing tools, it’s a great all-around choice.

UniOne – Reliable Email Delivery

UniOne builds a dependable email system that empowers developers and companies to deliver their marketing and transactional communications rapidly and efficiently.

Its scalable API lets users process 60 million emails per hour with flexible integration choices and advanced email performance tracking.

Key Stats

• 60 million emails/hour
• 200+ templates
• SMTP & HTTP API
• Real-time analytics

Plan	Monthly Cost	Emails/Month
Free	$0 for 4 months	6,000 with 100 email address validations
Standard	Pay-as-you-go	Up to 3 million mails
Professional	Custom	5 million+

Pros

• Scalable delivery infrastructure
• Generous free trial
• Easy API integration
• Real-time analytics and reports
• Responsive customer support

Cons

• Limited marketing automation features
• Can get expensive for very high volumes

Businesses and developers who require dependable email delivery at high volumes will find UniOne a useful solution. The API tools and analytics features deliver important benefits to users.

SendGrid – Marketing Focused Email Delivery

SendGrid delivers efficient email services that handle large transactional and promotional mailings at scale. The platform provides different application programming interfaces plus automation features alongside complete analytic reports.

Larger businesses and agency clients choose SendGrid for its extensive marketing capabilities and integrations. However, less technical users may find the interface complex.

Key Stats

• Handles over 60 billion emails/month
• 7 data centers globally
• Integrates with 100+ apps

Plan	Monthly Cost	Emails/Month
Free	$0	40,000
Essentials	$19.95	100,000
Professional	$89.95	200,000
Premier	$299.95	300,000

Pros

• Scales to very large volumes
• Extensive marketing automation
• Flexible APIs for developers
• Global infrastructure

Cons

• Complex interface for beginners
• Add-ons increase cost
• Lacks customer support for lower tiers

For high volume senders who also want marketing tools, SendGrid is a solid choice. But those just needing transaction basically delivery may find cheaper alternatives.

Mailgun – Developer-Friendly Email API

Mailgun focuses on powering transactional emails via their easy-to-integrate API. It shines for developers needing to handle all email handling programmatically.

It lacks extensive marketing tools but offers strong deliverability and segmentation capabilities that are out of the box.

Key Stats

• Sends over 150 million emails/day
• API libraries for Node.js, Ruby, PHP, and more
• Free tier with up to 6,000 emails/month

Plan	Monthly Cost	Emails/Month
Free	$0	6,000
Starter	$35	40,000
Professional	Custom	500,000+

Pros

• Fast and well-documented API
• Developer friendly
• Simple analytics dashboard

Cons

• Setup requires DNS knowledge
• Costly for mid to high volumes
• Limited marketing automation

Mailgun's API makes integration easy for developers when sending high volumes of transactional or automated emails. But keep in mind that costs scale rapidly.

Mailchimp Transactional – For Existing Mailchimp Users

The Mandrill email service was rebranded as Mailchimp Transactional. It focuses on extending Mailchimp’s marketing platform to include triggered emails.

For those already using Mailchimp, one of the best SMTP relay service providers, it offers a unified solution. But it may prove costly if you don’t need the full platform.

Key Stats

• Delivers over 13 billion transactional emails per month
• Automates email queueing and load balancing
• Integrates directly with the Mailchimp platform

Plan	Monthly Cost	Emails/Month
Pay As You Go	$0.10/thousand after free tier	5,000 free for the first month

Pros

• Unified with Mailchimp
• Scales to high volumes
• Excellent deliverability

Cons

• Expensive compared to standalone SMTP
• Confusing pricing structure
• Support is reported to be slow

If you want to extend an existing Mailchimp account, Mailchimp Transactional works well. However, costs are high when compared to other best SMTP providers.

Amazon SES – Affordable High-Volume Email

Amazon SES stands out for affordably when sending high volumes of email. It integrates tightly with other AWS services but lacks convenience features.

The pay-as-you-go model can offer significant cost savings at scale. However, much hands-on management is required to optimize deliverability.

Key Stats

• Over 14 trillion emails per year
• Handles spikes up to 50 million emails/hour
• Fully integrated with AWS infrastructure

Plan	Monthly Cost	Emails/Month
Pay As You Go	$0.10/1000 emails	62,000 in the first year, then declines

Pros

• Low cost for very high volumes
• Auto scales massively without effort
• Integrates seamlessly with the  AWS suite

Cons

• Hands-to optimize deliverability
• Steep learning curve
• Lackluster default deliverability

If your primary goal is extreme cost savings on high-volume email, the complexity tradeoff of Amazon SES may be worthwhile. But the basic fee for Amazon Web Services, required with Amazon SES, may cancel the effect for low volume users.

Mailjet – All-In-One Email Marketing

Mailjet helps businesses create and automate emails while also sending SMS messages and connecting to CRM platforms.

The full range of features costs more to use but only benefits large email sending businesses. Still, it can serve both marketing and transactional use cases.

Key Stats

• Sends over 9 billion emails/year
• Built-in image editor and templates
• Free tier up to 6,000 emails/month

Plan	Monthly Cost	Emails/Month
Free	$0	6,000
Essential	$17	15,000
Power	$42	40,000
Premier	$125	200,000

Pros

• All-in-one email and SMS
• Generous free tier
• Excellent deliverability

Cons

• Can get expensive at higher tiers
• Support may be very slow
• International phone support lacking

Unless you specifically want SMS capabilities alongside email, lower-cost providers will likely better suit most use cases. But Mailjet offers a generous free tier to test quality, so consider it yourself.

Postmark – Reliable Transactional Email

Postmark explicitly focuses on reliably powering high-volume transactional email with extensive tracking, analytics, and monitoring capabilities.

The straightforward but robust architecture provides exceptional deliverability and support. However, more advanced marketing tools are not offered.

Key Stats

• Delivers over 2 billion emails/month
• 99.9% best SMTP server uptime
• Free tier up to 100 emails/month

Plan	Monthly Cost	Emails/Month
Trial	$0	100
Starter	$15	10,000
Business	$30	25,000

Pros

• Fantastic deliverability
• Detailed email tracking
• Clear pricing structure
• Great support

Cons

• Lacks marketing features
• Potentially costly at huge volumes

If reliable delivery of transactional email is your priority, Postmark balances deliverability with transparent pricing very well. The lack of marketing tools is its only downside.

Conclusion & Recommendation

So, in summary, Mailtrap and UniOne are our top overall recommendations based on core infrastructure, generous free tier, deliverability rates, and support quality. The main limitation is the lack of sophisticated marketing automation tools.

However, SendGrid may suit larger businesses that need marketing and customization capabilities. Mailgun and Postmark are great for developers focused purely on transactional email. And Amazon SES is the most affordable high-volume option, albeit with a hands-on approach.

Hopefully our evaluation across the key criteria of infrastructure, pricing, features, and support will help you determine the best SMTP provider for your specific needs.