SMTP relay services are essential tools for sending emails reliably and efficiently across different domains. They act as intermediaries between a sender’s email client or server and the recipient’s mail server, ensuring smooth transmission of emails, especially in high-volume environments. SMTP relays are particularly useful for businesses handling transactional emails (such as order confirmations or password resets) or marketing campaigns, as they handle routing, queuing, and retries for undelivered messages. By outsourcing these tasks to a dedicated SMTP relay service, businesses can improve email deliverability, avoid blacklisting, and offload the infrastructure burden of maintaining their own mail servers.
Here is our list of the best SMTP relay services:
- MailerSend EDITOR’S CHOICE This is an SMTP relay service for transactional emails. It offers an intuitive interface, real-time tracking, and analytics, allowing businesses to ensure reliable email delivery with tools for collaboration and detailed insights for developers and marketers.
- SMTP2Go This reliable SMTP relay service is designed for high deliverability. It features global servers, real-time email tracking, and advanced analytics for transactional and marketing emails.
- SendPulse This platform provides an SMTP relay service and marketing automation tools with features like email personalization, reporting, and A/B testing.
- Brevo (formerly SendinBlue) This SMTP relay service for transactional and marketing emails includes email automation, segmentation, and tracking.
- Mailjet A package of an SMTP relay service with an email marketing suite with features like email automation, real-time analytics, and collaborative tools.
- Mailtrap An email testing tool with an SMTP relay service for advanced plans. It allows developers to safely test email workflows in staging environments.
In addition to handling the technical aspects of email delivery, many SMTP relay services offer advanced features like real-time tracking, analytics, IP reputation management, and support for email authentication protocols such as SPF, DKIM, and DMARC. These features help prevent spam, phishing, and spoofing, ensuring that emails reach recipients’ inboxes rather than being filtered as junk. The scalability and reliability offered by SMTP relays make them ideal for organizations of all sizes, from startups sending occasional transactional emails to enterprises delivering millions of marketing messages daily.
The Best SMTP Relay Services
SMTP relay systems need to be able to cater to both transactional emails, which are the automated response mails that business systems send out, and marketing emails, which can involve high volumes of emails.
Our methodology for selecting an SMTP relay service
- A high deliverability rate to maximize the chances of emails reaching the inbox rather than the spam folder.
- A service that can be easily integrated with existing systems, applications, or websites.
- A provider that can scale with a business as email volumes grow.
- A system with good customer support and a reliable infrastructure that can address any issues that may arise.
- Real-time analytics, bounce rate monitoring, custom DKIM keys, and the ability to separate transactional and marketing emails.
- A free trial or a free edition that enables an evaluation to be made without a long-term commitment.
- Value for money from a provider with a good reputation that offers its service at a reasonable price.
By carefully evaluating these criteria, we assembled a shortlist of SMTP relay services that implement email delivery effectively.
1. MailerSend
MailerSend is a modern email platform that provides powerful SMTP relay services tailored for transactional emails. Known for its ease of use and developer-friendly features. It enables businesses to send high volumes of email reliably.
Key Features:
- Real-time analytics: Detailed metrics for open rates, click rates, and bounce rates allow businesses to track performance and improve deliverability.
- Transactional email API: Offers easy integration with applications, enabling developers to send high-volume transactional emails effortlessly.
- Custom domains: Provides domain authentication (SPF, DKIM, DMARC) to enhance email security and boost sender reputation.
- Dedicated IPs: Available for larger senders, ensuring better control and monitoring of email deliverability and reputation.
- Team collaboration tools: Supports multiple users with role-based access, making it easier for teams to manage email campaigns and transactional messaging.
Whether you’re sending order confirmations, password resets, or other system-triggered emails, MailerSend’s infrastructure ensures that your messages are delivered quickly and efficiently. Backed by real-time analytics, collaborative tools, and secure email delivery, it’s a comprehensive solution for teams looking to enhance their email operations without the complexity of traditional services.
Why Do We Recommend It?
MailerSend excels in offering an easy-to-use SMTP relay service, perfect for businesses of any size. Its real-time analytics, advanced security features, and scalable API make it a powerful solution for managing transactional emails while maintaining optimal deliverability and security.
I found that MailerSend offers more than just an SMTP relay; it provides a complete email-sending infrastructure with an emphasis on simplicity and collaboration. Its easy API integration and ability to scale are key strengths, allowing businesses to send transactional emails at high volumes without worrying about server maintenance or email deliverability. It’s ideal for developers and marketing teams alike, providing both flexibility and performance in email handling.
Who Is It Recommended For?
MailerSend is recommended for developers and teams that need a reliable and scalable SMTP relay for transactional emails. It’s perfect for small to mid-sized businesses, SaaS platforms, and eCommerce companies seeking a user-friendly interface with detailed analytics and customization options for enhancing email performance.
Pros:
- Easy API integration: Developers can quickly integrate MailerSend into existing applications.
- High email deliverability: Strong domain authentication and IP management enhance inbox placement.
- User-friendly interface: Intuitive design simplifies managing large volumes of transactional emails.
- Collaboration tools: Multiple users can work together seamlessly, improving workflow for email operations.
- Excellent customer support: Responsive and helpful support for resolving issues quickly.
Cons:
- No free dedicated IP: Dedicated IPs are only available in higher plans.
MailerSend offers a flexible pricing model that caters to both small businesses and large enterprises. The free tier allows up to 12,000 emails per month, ideal for startups or testing environments. Paid plans start at $25/month for 50,000 emails, with additional features like dedicated IPs, priority support, and enhanced API limits.
EDITOR'S CHOICE
MailerSend is our top pick for an SMTP relay service because this cloud-based system is designed to facilitate the sending of transactional emails quickly and efficiently. It offers a user-friendly interface that simplifies the setup process, allowing users to send emails from any app, device, or email client with minimal configuration. One of MailerSend’s standout features is its high deliverability rate, achieved through the use of clean IP addresses and authenticated domain names, which helps ensure emails reach the inbox rather than the spam folder. The service also provides real-time analytics, enabling users to track email events such as bounces, clicks, and unsubscribes. MailerSend supports multiple integrations, including WordPress, Zapier, and Slack, making it versatile for various use cases. Additionally, it offers strong security features like SPF and DKIM protocols to authenticate emails and an IP allowlist to protect against unauthorized use. The service is scalable, allowing users to create multiple SMTP users for each domain and manage them easily through a single dashboard. MailerSend also boasts award-winning customer support, available 24/7 to assist with any issues. Overall, MailerSend is a reliable and efficient choice for businesses looking to streamline their email delivery process and improve their email marketing efforts.
OS: Cloud based
2. SMTP2Go
SMTP2Go is a highly reliable and secure SMTP relay service designed for businesses that need dependable email delivery for both transactional and marketing emails. With a strong focus on deliverability, SMTP2Go helps businesses ensure their emails reach inboxes by providing real-time analytics, spam filter testing, and advanced security protocols. It is an ideal solution for businesses of any size, offering a simple yet powerful platform to handle bulk email sending with minimal hassle.
Key Features:
- Global server network: SMTP2Go uses a global network of servers to ensure high deliverability and faster email processing, regardless of geographic location.
- Real-time email tracking: Comprehensive analytics provide insights into delivery status, bounce rates, and engagement metrics such as open and click rates.
- Spam filter testing: Built-in tools allow users to test emails against spam filters to improve inbox placement and reduce bounce rates.
- API and integration: Offers a flexible API for developers to easily integrate SMTP2Go with existing systems, as well as ready integrations with popular platforms.
Why Do We Recommend It?
SMTP2Go stands out for its global server network, ensuring high deliverability and uptime. I noted that with delivery analytics, spam filter testing, and strong security features, it’s an excellent solution for businesses that need reliable email delivery, backed by responsive 24/7 support.
Who Is It Recommended For?
SMTP2Go is recommended for businesses and developers seeking a reliable SMTP relay service for sending high volumes of email, both transactional and marketing. It’s particularly suited for companies that require detailed reporting, advanced security, and seamless integration with existing platforms.
Pros:
- High email deliverability: Global server network ensures fast and reliable email delivery across the world.
- Comprehensive email analytics: Detailed reports on delivery status, engagement, and bounce rates.
- Spam filter testing: Ensures emails are optimized for inbox placement.
- Reliable 24/7 customer support: Offers multiple channels of support with fast response times.
Cons:
- Limited free plan: The free plan is restrictive and may not be sufficient for businesses sending high volumes of email.
SMTP2Go offers a range of pricing plans to suit businesses of all sizes. The free plan includes 1,000 emails per month, making it a good option for small businesses or testing. Paid plans start at $10/month for up to 10,000 emails.
3. SendPulse
SendPulse is an all-in-one marketing platform that provides a reliable SMTP relay service for sending transactional and promotional emails. Known for its multi-channel approach, SendPulse enables businesses to send emails alongside SMS, push notifications, and chatbots, making it a versatile tool for both marketing and transactional email needs. Its SMTP relay service is designed for seamless integration, ensuring high deliverability and optimal performance for businesses of all sizes.
Key Features:
- Multi-channel marketing: SendPulse combines email with SMS, push notifications, and chatbots, offering a unified platform for customer engagement.
- SMTP relay for transactional emails: Reliable email delivery with easy integration for transactional messages like receipts, order confirmations, and password resets.
- A/B testing: Test email campaigns to determine the best-performing content, ensuring higher engagement and deliverability.
Why Do We Recommend It?
We recommend SendPulse for its powerful multi-channel capabilities, which allow businesses to manage not only email but also SMS and push notifications from a single platform. I learned that the combination of reliable SMTP relay services and user-friendly automation makes it a strong choice for diverse communication needs.
Who Is It Recommended For?
SendPulse is ideal for small to medium-sized businesses and marketers who want to combine transactional emails with a wider marketing strategy. Its SMTP relay service is perfect for businesses needing to automate email workflows and track detailed analytics for better performance across marketing channels.
Pros:
- Automation tools: Advanced automation for drip campaigns, personalized messaging, and triggered emails based on user behavior.
- Detailed analytics: Track open rates, click rates, bounce rates, and other performance metrics to optimize email delivery and engagement.
- Multi-channel communication: SendPulse supports email, SMS, push notifications, and chatbots in one platform.
Cons:
- Limited template designs: Email template customization options are somewhat limited compared to other platforms.
SendPulse offers a free plan that includes 15,000 emails per month to 500 subscribers, making it accessible for small businesses starting out. Paid plans start at $6.40/month for up to 1,000 subscribers.
5. Brevo (formerly SendinBlue)
Brevo, formerly known as SendinBlue, provides an SMTP relay service alongside a comprehensive suite of email marketing and automation tools. Focused on simplifying email campaigns, Brevo provides scalable SMTP relay solutions for businesses of all sizes, ensuring high email deliverability for transactional and marketing emails. The platform also supports SMS, chat, and CRM functionalities, making it a versatile choice for businesses looking for an all-in-one communication solution.
Key Features:
- Transactional and marketing emails: Brevo’s SMTP relay ensures reliable delivery of high-volume transactional emails alongside comprehensive marketing campaign management.
- Advanced email automation: Set up triggered emails, customer journeys, and personalized workflows based on customer behavior.
- Real-time analytics: Detailed tracking for open rates, clicks, bounces, and overall performance, helping businesses optimize their email strategy.
Why Do We Recommend It?
Brevo is a versatile and scalable platform offering both SMTP relay services and advanced email marketing features. I discovered that its user-friendly automation tools, comprehensive analytics, and multi-channel capabilities make it an excellent choice for businesses seeking to manage both transactional and marketing emails effectively.
Who Is It Recommended For?
Brevo is recommended for small to medium-sized businesses that want a reliable SMTP relay service combined with comprehensive email marketing and automation tools. It’s particularly suited for businesses that need an integrated approach to email, SMS, and CRM, helping to streamline their customer communication efforts.
Pros:
- SMS and CRM integration: Manage SMS campaigns and customer relationships from a single platform to enhance multi-channel engagement.
- Dedicated IPs: Available for better email control and reputation management, ensuring high deliverability rates.
- Multi-channel support: Offers email, SMS, chat, and CRM features in one platform.
Cons:
- Limited template customization: The email template builder offers fewer customization options compared to other platforms.
Brevo offers a free plan that allows users to send up to 300 emails per day, ideal for small businesses or those just starting. Paid plans start at $25/month for 20,000 emails, with additional features such as advanced reporting, A/B testing, and no daily sending limits.
5. Mailjet
Mailjet is a reliable SMTP relay service that caters to businesses needing to send transactional and marketing emails. Known for its collaborative email-building tools, Mailjet offers high deliverability rates and scalable plans, making it suitable for businesses of all sizes. Its easy-to-use platform allows teams to work together seamlessly, creating and managing email campaigns while providing real-time tracking and analytics to optimize email performance.
Key Features:
- Collaborative email builder: Teams can work together in real-time to design, edit, and approve emails, enhancing workflow and creativity.
- SMTP relay for transactional emails: Ensures fast and reliable delivery of transactional messages like order confirmations, receipts, and account notifications.
- Advanced email automation: Automate triggered emails based on customer behavior, making personalization and segmentation easy.
Why Do We Recommend It?
We recommend Mailjet for its intuitive interface and collaborative tools, making it ideal for teams that need to work together on email campaigns. I observed that its reliable SMTP relay service ensures smooth delivery of both transactional and marketing emails, and real-time analytics help businesses optimize performance.
Who Is It Recommended For?
Mailjet is recommended for teams and businesses that require a user-friendly email platform with strong collaboration tools. It’s particularly suitable for marketing teams and developers looking for a seamless way to manage both transactional emails and marketing campaigns from a single platform.
Pros:
- Real-time analytics: Track open rates, click rates, bounces, and other key metrics to improve email campaign performance.
- Dedicated IPs: Available for businesses that want better control over their sender reputation and improved deliverability.
- User-friendly interface: Easy-to-navigate platform suitable for both beginners and experienced users.
Cons:
- Advanced features require higher tiers: Automation workflows and dedicated IPs are only available in premium plans.
Mailjet offers a free plan with 6,000 emails per month with a limit of 200 emails per day – that’s perfect for small businesses or basic use. Paid plans start at $15/month for 15,000 emails with no daily sending limit.
6. Mailtrap
Mailtrap is a versatile email platform primarily designed for safe email testing, but it also offers an SMTP relay service in its advanced plans. It allows developers to test, preview, and debug email workflows before going live, ensuring that emails are properly configured and functional. The SMTP relay service provides reliable email delivery for transactional emails, making it a valuable tool for development teams aiming to streamline their email testing and production processes.
Key Features:
- Safe email testing: Mailtrap’s sandbox environment allows developers to test email workflows without sending emails to actual recipients.
- SMTP relay for transactional emails: Secure and reliable email delivery for live environments in advanced plans, ensuring that transactional emails like password resets and confirmations reach inboxes.
- Email debugging: Inspect and debug emails by viewing headers, body content, and attachments to ensure everything works as expected before production.
Why Do We Recommend It?
Mailtrap excels in offering a secure environment for testing email workflows and ensuring smooth transactional email delivery in production. I noticed that its combination of testing, debugging, and SMTP relay services makes it ideal for development teams needing to guarantee email functionality and deliverability.
Who Is It Recommended For?
Mailtrap is recommended for development teams, SaaS platforms, and businesses that need to thoroughly test and debug their email workflows before sending them to users. It is ideal for developers who require a safe testing environment combined with a reliable SMTP relay service for live transactional emails.
Pros:
- Analytics and reports: Track the performance of your email tests with detailed analytics on deliverability, spam scores, and more.
- Integration with popular tools: Easily integrates with various development tools and CI/CD pipelines, making email testing a seamless part of the development process.
- Safe email testing environment: Allows developers to test without the risk of spamming real recipients.
Cons:
- SMTP relay only in higher plans: The SMTP relay service is available only in the advanced paid plans.
Mailtrap offers a free plan that includes limited email testing with up to 500 test emails per inbox per month. Paid plans start at $9.99/month, providing access to additional features like the SMTP relay service and higher testing volumes.
