Free SMTP Server List: Top 10 Most Popular SMTP Services in 2021

List of the best free SMTP Servers and SMTP Services:

SMTP service is a system of rules which is used to send email messages between the servers.

Whereas SMTP relay service is a third-party application or service which is used to transfer the email messages between different hosting services, servers, and domains.

SMTP Servers are the machines which are implemented for email delivery. Generally, servers have a limit on the number of emails to be sent per day. Hence for sending emails in bulk, you should go for a professional SMTP server.

SMTP services

What is SMTP Authentication?

SMTP authentication is the process in which ISP clients identify themselves to the mail server from which they are going to send an email.

SMTP server is used for sending emails. Google provides the free SMTP server through Gmail service. Anyone can send emails using Gmail and it is for free. This service can be used for sending personal emails or can be used even with your website. You can use this service for sending newsletters, contact forms, and notifications.

SMTP test tools: SMTP test tools or SMTP diagnostics tools are useful to identify and troubleshoot SMTP server problems. For this, it sends a message to the SMTP server. All these trials are displayed or recorded in a log.

=> Contact us to suggest a listing here.

Free SMTP Server List And Best SMTP Services In 2021

Enlisted below are the most popular free SMTP servers and services that are available in the market.

Comparison Of The Top SMTP Services

SMTP ServicesUsed ForPriceUsersSupported languages, frameworks, and libraries

SendinBlue Logo
SMTP, email marketing, SMS, and marketing automation.Free plan.Price starts at $25 for sending 40000 emails per month.BusinessesCompatible with many tools like WordPress, Drupal, WooCommerce, Google Analytics, & Salesforce etc.

Email Newsletter, Shipping Notifications, Promotional Emails, & Password ResetsFree plan, Essentials: Starts at $9.95/month, Pro: Starts at $79.95 per month, Premier: Custom.Developers & Marketers.Frameworks and client libraries. PHP, Python, Ruby, Java, Node.js, Go, C#.
Amazon SES

Marketing, Notification. & Transactional emailsPrice starts at $0.10.Businesses & DevelopersIntegration with other AWS services.

Data-driven emails,E-commerce,Personalized one-to-one messages. 1-20 blocks: $20 per block. 21-40 blocks: $18 per block.…Mailchimp usersPHP, Ruby, Python.

Used for better email deliverability.Free: 15000 emails The plan starts at $9 for 50000 emails.Developers.It can be used with big and small applications. It will help you in embedding the email with your app, website, or product.

Let’s Explore!!

#1) Sendinblue

SendinBlue Logo

Sendinblue is the best SMTP email service provider on the market.

Sendinblue SMTP Statistics

Sendinblue provides a platform for SMTP, email marketing, SMS, and marketing automation. With SMTP, it helps in optimizing transactional emails and ensures on-time delivery.


  • For campaigns, it provides real-time statistics.
  • Dedicated IP addresses.
  • It provides a performance dashboard.
  • It will give you a record for each email sent.
  • While integrating with Sendinblue SMTP, it allows you to select API, Classic SMTP parameters, Postfix Configuration, and Sendinblue PHP library.

Price: Based on the number of emails, there are five plans.

Plan Number of emailsPrice per month
Free Plan300/dayFree.

#2) Mailjet

Best For: It is good for SMTP service.


Mailjet is an email service for creating, managing, sending, and optimizing emails. It provides a transactional email service for marketers and developers. It provides SMTP Relay or Send API for bulk emails.

Suggested reading =>> Mailjet- A comprehensive review


  • Email designing with the team.
  • Easy to design an email because of the drag-and-drop editor.
  • In-depth analytics.
  • Real-time collaboration.

Price: There are four plans, i.e. Free, Basic, Premium, and Enterprise. To know more about the Enterprise plan, you can request a quote. Below mentioned prices are applicable if you are billed annually.

No. of emailsFreeBasicPremium

Visit Website: Mailjet

#3) SendGrid

Best For: Email marketing and as a transactional email API.


SendGrid provides the best email delivery service.

It provides APIs, SMTP Relays, and Webhooks. It promises fast and customizable integration. Support is provided through videos, online community, and documentation. This single email platform can be shared with the team.

Recommended reading =>> Top SendGrid Competitors


    • SendGrid API and SMTP integrations will help you for transactional email requirements.
    • It provides flexible API and SMTP setup.
    • It offers dedicated IP addresses.
    • It includes many other email deliverability features like reputation monitoring and email authentication.


PlansNumber of emails/monthPrice
Free40000 for 30 days then 100/day$0
Pro100000-1.5 million$79.95
PremierMore than 1.5 millionCustom

Website: SendGrid

#4) Amazon SES

Best For: It is a great platform at a low price. It is a reliable service.

Amazon SES

Amazon SES is an email sending and receiving platform that can be used for transactional messages, marketing communications, notifications, and for incoming emails.

This SMTP interface allows integrating email sending capabilities into your current ticketing system or email clients.


  • Using SMTP interface or AWS SDKs, Amazon SES can be directly integrated into your applications.
  • It provides easy to use mailbox simulator.
  • Amazon SES can be integrated with other AWS services.
  • Dedicated IP addresses.


Email from an application on Amazon EC2First 62,000 emails are free. There onwards it will cost $0.10 for 1000 emails. For attachments sending: $0.12 for one GB.
Email client or another software package $0.10 for 1000 emails.For attachments sending: $0.12 for one GB.
Email receivingFree for 1000 emails. There onwards $0.10 for 1000 emails. For incoming email chunks: $0.09 for 1000 emails

Website: Amazon SES

#5) Mandrill

Best For: This service is made for developers. It is best for transactional emails.


For MailChimp users, Mandrill provides transactional email services. It is for data-driven emails like e-commerce or personalized one-to-one messages. You can send and track emails through API or SMTP integration.


  • It provides dedicated IP addresses.
  • It allows you to send from multiple domains for each account.
  • It provides in-depth analytics.

Price: Dedicated IP can be added for $29.95 per month.

EmailsBlocksPrice per block
1-500KJanuary 1, 2020$20
More than 4 MMore than 161$10

Website: Mandrill

#6) SparkPost

Best For: Best for Email Deliverability. It is a scalable Email delivery system for developers.


It is an email delivery service which can be used by small and big companies. It will help you from creating customer engagement email to better delivery of an email. It provides flexible pricing plans.


  • It helps in optimizing customer engagement through predictive insights.
  • Real-time email analytics.
  • It will improve email deliverability.
  • It helps you to embed emails into your app, product, or website.
  • It offers support for dedicated IP addresses and it is a paid feature.
  • It provides analysis for the deliverability of emails.

Price: There are three pricing plans, i.e. Standard, Premium, and Enterprise. To know more details about the Premium and Enterprise plan you will have to contact the company.

No. of emailsStandard Plan prices per month
1M $474

Website: SparkPost

#7) Mailgun

Best For: It provides the best SMTP service and good transactional email service.


Mailgun provides Email API, Email Validation, and deliverability services. It supports burst sending, and with this service, you can send up to 250000 emails per minute. It provides easy SMTP integration.


  • Advanced email analytics.
  • IP allocation management.
  • Sending transactional and bulk emails is easier with the help of SMTP integration and RESTful API.
  • It provides email validation.

Price: Price depends on the number of emails and the number of validations you require. Here only a few plans are mentioned. Prices mentioned here are based on the number of emails for 100 validations.

EmailsPrice per month
More than 5000000Custom

Website: Mailgun

#8) Postmark

Best For: System is made for developers and is best for transactional emails.


Postmark SMTP servers are in San Jose, Newark, and Amsterdam.

It automatically selects the nearest server for your transactional email. SMTP differs from REST API in their response codes. For REST API, you will immediately get a success or error message for the sent message. While SMTP accepts every message and logs bounces for the error.


Ports: 25, 2525, 587.


  • It tracks the messages using custom metadata.
  • It allows you to group common types of messages.
  • It provides developer-friendly SMTP documentation.


Emails/monthPriceFor 1000 extra emails

Website: Postmark

#9) MailGet SMTP

Best For: Email marketing.


It is an SMTP Relay service.

MailGet SMTP will help you to send emails for marketing, alerts, receipts, invoices, registrations, and notifications. You can use this service for bulk emailing and they have their private servers.


  • Deliverability: It assures you to deliver email to the inbox.
  • They have whitelisted servers.
  • It allows you to send bulk emails and emails from multiple verified domains.
  • Authentication is provided using SPF validation and DKIM signature.


Plan NameNumber of emails/monthPrice per month

Website: MailGet_SMTP

#10) MailGet Bolt

Best For: Email marketing.


It is an email service to send Marketing, Educational, Informative, and Promotional emails.

It provides many features like email scheduling, autoresponders, list management, list cleaning etc. It helps you in building emails with the drag-and-drop facility.


  • It allows you to add unlimited custom tags.
  • It provides more than 500 custom designed templates for email.
  • It supports importing of email contacts using CSV files or you can add them manually.
  • It has auto-send options for the follow-up process.
  • Series of emails can also be sent automatically.


PlansSend emails to- Number of subscribersPrice per month

Website: MailGet Bolt

Few SMTP test and diagnostics tools are listed here:

SMTP Test Tool


This was all about the SMTP services, SMTP Relay, and Free SMTP server. If we compare the top two services i.e. Sendinblue and SendGrid for features, there is an absence of email preview and email re-send functionality in SendGrid.

Amazon provides the best email services at low prices. Amazon pricing plans are more flexible and affordable. If we compare Send Grid, Mailgun, SparkPost, and Pepipost for the price then Pepipost has more affordable plans.

Hope you will found this article helpful in knowing about SMTP services, SMTP Relay, and Free SMTP server.

=> Contact us to suggest a listing here.