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I compared the 7 most popular SMTP providers to find out the best pics for software engineers and email marketers.
In the following section, I give you a snapshot of the top contenders, the methodology on how to make an educated choice, and the in-depth reviews of each provider.
Let’s dive in.
Best SMTP service providers: snapshot
- Mailtrap Email Delivery Platform is best for companies sending at scale looking for a reliable SMTP with high email deliverability by design and industry-best analytics.
- SendGrid: for large businesses seeking marketing tools alongside SMTP email delivery.
- Mailgun: for businesses looking for a straightforward SMTP service, but also well-documented APIs.
- Mailchimp Transactional Email: for existing Mailchimp users looking to extend Mailchimp’s marketing services to transactional (user-triggered) emails.
- Amazon SES: best for tech-savvy users who prefer a cost-effective service and a completely manual setup process (a lot of coding required).
- Mailjet: for businesses that want to do SMS marketing on top of emails at a scale.
- Postmark: for businesses that want a straightforward SMTP service to send user generated or bulk emails.
Here’s a tabular overview of each provider, click on the links to jump to individual reviews.
| SMTP provider | Free plan | Pricing |
| Mailtrap | 3,500 emails/month | Starts at $15/month for 10,000 emails |
| SendGrid | 100 emails/day | Starts at $15/month for 15,000 emails |
| Mailgun | 6,000 emails/month | Starts at $15/month for 10,000 emails |
| Mailchimp | 1000 emails/month | $12.30/month for 5000 emails |
| Amazon SES | 3,000 emails/month for the first 12 months | Pay-as-you-go $0.10 per 1000 emails + additional fees |
| Mailjet | 6,000 emails/month | Starts at $17/month for 15,000 emails |
| Postmark | Free trial only | Starts at $15/month for 10,000 emails |
*Pricing information is based on data available as of January 2025. For the most up-to-date pricing details, visit providers’ official websites.
SMTP providers comparison criteria
When comparing the SMTP (Simple Mail Transfer Protocol) providers, I was looking for an optimal balance of their email infrastructure, pricing, customer experience, and the overall features offering.
Additionally, I check their marketing platform (if there’s any) and the email tracking options.
Read on for more details.
Email Infrastructure
I’ll be talking about deliverability, reliability, and scalability.
Deliverability
A strong focus on email deliverability entails:
- Email authentication via DKIM, SPF, and DMARC
- Bounces and spam complaints monitoring
- Webhooks for real-time event notifications
- Suppression lists for basic segmentation and recipient management
- Dedicated IP address for high volume senders
Note: To the above, I’m assuming you’re a trusted sender and your domain name hasn’t been blacklisted. If not, you’ll need to fix the reputation first to avoid your emails going straight to the spam folder.
However, not all SMTP providers perform equally well when it comes to deliverability and inbox placement. We conducted an independent deliverability test to compare providers under identical conditions:
- Free plan
- Shared IPs
- Same email template
- Seed testing for inbox placement monitoring
Here’s how each SMTP provider performed:
| SMTP service | Email placement results |
| Mailtrap | Inbox: 78.8% Tabs: 4.8% Spam: 14.4% Missing: 2.0% |
| Amazon SES | Inbox: 77.1% Tabs: 1.9% Spam: 20.0% Missing: 1.0% |
| Mailgun | Inbox: 71.4% Tabs: 3.8% Spam: 23.8% Missing: 1.0% |
| SendGrid | Inbox: 61.0% Tabs: 1.0% Spam: 17.1% Missing: 20.9% |
| Postmark | Inbox: 83.3% Tabs: 1.0% Spam: 14.3% Missing: 0.9% |
For the full results and methodology, check out our email deliverability comparison blog.
Reliability
You need an SMTP provider that guarantees high uptime and minimal service interruptions (even with a free SMTP server). Look for providers with a track record of redundant infrastructure, and robust disaster recovery mechanisms, involving:
- Multiple servers (data centers or server locations)
- Storage systems to prevent single points of failure and minimize downtime
- Network redundancy (redundant network connections from different providers)
- Load balancing and failover mechanisms (Mailtrap offers ActionMailer balancer you can use to further strengthen your email infrastructure if one SMTP email service fails. Check it out at GitHub.)
Scalability
Consider the volume of emails you anticipate sending and whether the provider offers flexible plans or pricing tiers to accommodate your growth. For example, the Mailtrap Email API/SMTP Basic plan starts at 10K emails a month for $10. But if it turns out you need 100K emails a month, you can easily scale to a higher plan without paying 10x the price.
Pricing
When selecting providers, I focus on transparent and reasonable pricing plans. Basically, my goal is to give you the best balance of reliable email infrastructure and features without compromising delivery rates.
But, I don’t know your budget or feature requirements. So, when reviewing the providers I offer a detailed features overview and the current pricing.
Note that not all providers have the same pricing structure. I’ll tell you exactly where you need to pay attention, particularly if you send at a volume or need extra email tools.
Compliance
Regulatory compliance isn’t optional, especially for industries like FinTech, healthcare, or legal. When evaluating SMTP providers, make it a priority to check for the following key standards and features:
- Certifications: Look for SOC 2 Type II and ISO 27001.
- GDPR / HIPAA support: Ensure data is protected in transit and at rest.
- Authentication & access controls: Evaluate enforcement of SPF, DKIM, DMARC, rotating keys, and API key scoping.
- Auditability: Confirm detailed email logs, encryption, and access-level information tracking.
To help with the evaluation, I conducted a detailed comparison of the SMTP services featured in this article. Here’s a quick summary:
| Mailtrap | Mailgun | SendGrid | Amazon SES | Postmark | |
| Regulations Compliance | High | High | High | Configuration Dependent | High |
| Data Residency | EU/US | EU/US | Global | Multiple Regions | US |
| Auditing & Accountability | Excellent | Good | Very Good | Detailed | Good |
| Access & User Controls | Granular | Good | Very Good | Extensive | Good |
| Data Control & Retention | Flexible | Flexible | Flexible | Configurable | Flexible |
| Legal Compliance | Strong | Strong | Strong | Strong | Strong |
| Certifications | ISO 27001 | SOC 2 | SOC 2, ISO | Many (AWS) | SOC 2 |
If you’re interested to learn methodology or compare the providers in detail, please, visit our SMTP providers compliance comparison.
Customer support and user experience
Look for providers that offer a few support channels, such as live chat, email, or phone support.
Go to forums, social media, and software catalog websites and check the presence of the service you chose. Pay special attention to the reviews and comments sections and how fast (if at all) the service representative answers user questions and negative comments.
Then, move on to check the providers’ documentation. This will help you determine how fast and easy it would be to start using the SMTP service. The documents also give you the first glimpse into the complexity of the software and the UX.
For example, at Mailtrap, we provide our customers with the following:
- Help docs with detailed setup and troubleshooting guides.
- Blog with detailed guides including usable code and templates.
- YouTube channel with visual guides and step-by-step tutorials.
Transactional email sending
For me, one of the first tell tale signs of a good provider is the option to send user-triggered emails. This goes double if they offer powerful APIs and SDKs for different programming languages (Python, PHP, Node.js, etc.).
With that said, I check the API docs to ensure everything is well-documented. And also snoop around the internet to see what other users are saying about the deliverability and ease of use of the service.
Now, why should you care about the user-triggered emails and APIs?
First, APIs allow you to automate much of the email sending from your app or service. Next, user-triggered emails (like the sign-up confirmation) are among the first touchpoints with the customer. Therefore you should be sure they work seamlessly with any email client and help your brand shine.
Additionally, providers should offer tools that can help you with this, especially if you’re still in development. Some examples are Mailtrap MCP and Postmark MCP, which, for instance, you can hook up to your IDE and send your emails or simply smoothen out your workflow.
While tools like these are not necessary at all and are fairly new, they are certainly a quality-of-life update.
Marketing email sending
I’m a marketer, so I typically look for the automation options and customer segmentation. Then, I check how easy it is to create emails (e.g. drag-and-drop interface). And ideally, I would be able to upload the HTML templates that I already have.
As for the customer segmentation, I want the ability to import my email list and an easy way to map the recipients to the respective emails and campaign cohorts. Plus, it should be easy for me to remove inactive customers, unsubscribes, and bounces (e.g. like a list management option that show who has never responded or interacted with my emails).
Lastly, it’s great to have A/B testing to make it easier to gauge what type of emails resonate the best with each client cohort.
Now, before going into reviews, I need to stress that most providers don’t offer all the email marketing services with a basic plan. But that’s typical and expected.
Disclaimer: The reviews below contain software catalog ratings, pricing, and feature lists. These were valid at the time of writing, but could be subject to change by the time you’re reading this article.
Best SMTP provider: Mailtrap Email Delivery Platform
Mailtrap Email Delivery Platform is designed for product companies with high sending volumes. It’s ideal for development teams looking for a reliable SMTP provider with a strong focus on high email deliverability and top-notch developers’ experience.
Mailtrap provides 25+ ready-to-use code snippets for quick and easy integration with your application.
And to show you how dedicated we are to deliverability, I ran a test with GlockApps, showing 93.2% of emails via our SMTP reach in inbox or tabs (only 5.8% go to tabs).
So, to no surprise, some of Mailtrap’s clients include StackOverflow, PayPal, Atlassian, and Adobe.
Pricing
The free tier that allows users to send up to 3,500 emails per month. This free plan is quite generous, especially since it includes webhooks, email analytics, suppression management, and more.
For businesses with large-scale sending, I recommend going with our the most popular Business plan. Starting at $85 per month, it includes up to 100,000 contacts per month, deliverability team support, a dedicated IP, and much more. Check our Pricing page for the details.
Pros & cons
Pros
- Mailtrap provides a secure (TLS/SSL) and reliable infrastructure for production emails.
- There’s a team of people to ensure our systems and IPs are spammer-free without making you fill out lengthy verification forms.
- There are clear setup instructions for many different project types with an intuitive setup wizard, making it easy to integrate into your application.
- You get actionable in-depth analytics with helicopter view dashboard, drill-down reports, and email logs to control how your email infrastructure performs.
- Mailtrap upholds GDPR compliance and its ISO 27001 certification for all Email API/SMTP plans.
- 24/7 human support is there to address all your questions with deliverability experts on hand.
- Separate streams for transactional and bulk emails.
- It offers an integration to MCP servers via Claude, Cursor, or VSC code editor.
Cons
- Currently, you can only integrate Mailtrap with services such as Zapier and Tabular email, but more integrations are on the way.
SendGrid
SendGrid is tailored primarily for developers and marketers who need a scalable email delivery service that integrates well with various applications. It’s suited for businesses that manage large-scale user generated and marketing emails through one platform.
However, you should be aware that some users stress complexity of setup and slow support services when choosing their plan. Also, if you need 2FA, you can do it only with Authy, or via SMS, which is hardly the proper authentication method for email infrastructure because it’s baked to a phone number.
Pricing
SendGrid offers a tiered pricing structure segmented into plans for developers and marketers, both include a free plan.
- For developers, the Essentials plan starts at $19.95 a month.
- For marketers, the Basic plan starts at $15 a month.
At first glance, the pricing seems pretty straightforward. But be aware that the actual structure is quite complex and there are quite a few upsells and add-ons that may quickly bump up the actual cost.
For instance, the Essentials plan for developers does offer 100K emails a month. But you can have only one team member, there’s no dedicated IP, or SSO. To get those features, you need to choose a higher plan at $89.95 a month.
Pros
- Comprehensive APIs: Robust APIs for email activities, including detailed analytics for campaign optimization.
- Scalability: Handles large volumes.
- Integration: Possible integration with various platforms and applications.
Cons
- Complex setup: The initial setup and integration process is complex, especially when handling advanced features.
- Customer support: The support can be slow, particularly on the lower-tier plans.
- Marketing automation: Only available on the Advanced marketing plan.
If you’re looking for more alternatives to SendGrid, check the linked article.
Mailgun
Mailgun is designed for developers who need a programmable SMTP service for user-triggered emails. And, as of recently, Mailgun also has a marketing service.
Usually, this SMTP provider is favored by tech-savvy users to manage emails at a volume with precise control and detailed insights. And it’s mostly suitable for small businesses.
But, you should be prepared for somewhat clunky authentication experience via DNS records. Also, you should closely consider the total cost of ownership at high volumes.
Pricing
Mailgun offers a free plan and several tiered plans provide more features and higher sending limits. The Basic plan starts at $15 per month but pay close attention to limitations particularly if you’re working in a team.
Pros
- Flexible API: Mailgun’s API is developer-friendly, supporting custom integrations and automations.
- Strong deliverability: Includes sophisticated email validation tools to enhance inbox placement rates.
- Scalability: Effectively scales to accommodate growing email requirements without loss of performance.
Cons
- Learning curve: The platform’s robust features can be complex, requiring a steeper learning curve for new users.
- Pricing for high volumes: Costs can escalate quickly with higher volume tiers, which might not be cost-effective for all businesses.
- DNS records: No option to share DNS with anyone.
For more Mailgun alternatives, check the article I linked here. Also, we have a comprehensive Mailgun vs. SendGrid comparison, hit the link to jump to the article.
Mailchimp Transactional Email
G2: 4.2 Capterra: N/A
Formerly known as Mandrill, Mailchimp Transactional Email is for those who already use Mailchimp for marketing emails and want a cohesive toolset that blends marketing and user-triggered communications.
However, the cost and platform complexity can be considerations for businesses not already invested in the Mailchimp ecosystem.
Pricing
Mailchimp Transactional Email is an add-on to the main Mailchimp account and requires users to be on a paid Mailchimp plan. Pricing is based on the volume of emails sent, with blocks of emails available for purchase. The cost per email block decreases as volume increases.
Now, I wouldn’t say that the pricing isn’t transparent, but the whole block thing is confusing.
So, I recommend you use their calculator to estimate the pricing. For instance, if you want to send 100K user-triggered emails, Mailchimp separates it into 4 blocks, $20 each, meaning you pay $80 a month.
Pros
- Integrations: Mailchimp allows for integrations with several platforms including Salesforce, Shopify, Wix, and interestingly Canva.
- User-friendly interface: A straightforward drag-and-drop editor and a lot of pre-designed templates.
- Features: Includes A/B testing, time-warp sending, and detailed analytics, but mind the limitations based on your plan.
- Reliability: Built-in compliance and reputation monitoring.
Cons
- Cost: Can be expensive for those who need high volumes of emails, as it requires a Mailchimp plan plus additional charges for transactional emails.
- Complexity for non-marketers: While it integrates well with Mailchimp, users not familiar with Mailchimp’s platform may find it less intuitive.
- Support limitations: The support can be slow or less helpful than expected, particularly for technical issues.
If you want to find out how Mailchimp Transactional stacks up against its competitors, go to the linked article. And we have two more tutorials that can help you make a more informed decision:
- Sendgrid vs Mandrill vs Mailgun – How to Choose?
- Sendgrid vs Mailchimp: Design, Deliverability, Marketing
Amazon SES
Amazon Simple Email Service (SES) is designed for developers who seek a highly scalable and cost-effective email-sending and receiving solution. It’s especially suitable for those already integrated into the AWS ecosystem – for instance, S3 and Lambda users.
To stress, SES is only for tech-savvy businesses with dedicated email infrastructure teams looking for an affordable, scalable email solution within the AWS cloud-based services. Also, be aware of the potential need for additional AWS support services.
Pricing
Amazon SES uses a pay-as-you-go pricing model that charges based on the number of emails sent and received, and the data transferred.
For instance, at the lowest tier, you pay $0.10 per 1000 outbound emails, and the same goes for inbound. However, their pricing is quite structured and complex so you may want to check the official page to determine if it’s the right fit.
Pros
- Cost-effectiveness: Competitive pricing, especially beneficial for large-volume senders.
- High scalability: Easily handles large spikes in email volumes without service degradation, thanks to AWS infrastructure.
- Flexible deployment: Offers options for sending emails directly from an application or using the SES API, SMTP interface, or AWS SDK.
- Integration with AWS: Full integration with other AWS services enhances the functionality for users already within the AWS ecosystem.
Cons
- Complex setup: Complex to configure and integrate, particularly for users not familiar with AWS services.
- Limited features: While powerful, it lacks some of the more user-friendly features found in other email service providers, such as built-in marketing tools or visual email builders.
- Customer support: As with many AWS services, support can be expensive; the basic level of support might not meet the needs of all users, and higher levels of support come at a premium.
If you’re interested in Amazon SES alternatives, check the article I linked.
Mailjet
Mailjet is mostly designed for email marketing campaigns with a straightforward SMTP server provider that gives you the option to send user-triggered emails. And it’s attractive for teams that require collaborative tools to design, send, and track emails.
For instance, if you need an SMTP relay service for a WordPress website or an ecommerce, Mailjet could be a good choice. However, you should consider the cost implications of scaling and the degree of customization needed.
Pricing
Mailjet provides a flexible tiered pricing structure that includes a free tier. Note that the free plan includes Mailjet branding so it could be useful for testing only. And the Essential paid plan starts at $17 a month.
Pros
- User-friendly interface: Features an intuitive drag-and-drop email editor and a collaborative toolset, making it easy for teams to work together on email campaigns.
- Dual functionality: Supports user generated and marketing emails effectively.
- EU Data Compliance: Strong adherence to European data protection standards, making it ideal for businesses concerned with GDPR compliance.
Cons
- Limited customization: While the interface is user-friendly, you might find the customization options for templates somewhat restrictive.
- Pricing for high-volume senders: As email volumes increase, the cost can escalate significantly, which may not be optimal for larger businesses.
Guess what, we also blogged about Mailjet alternatives (10 of them actually). So, check them out.
Postmark
Postmark is for marketers and devs who require bulk and user-triggered emails without compromising on reliability.
If you have an enterprise level application or wordpress site and prioritize immediate email delivery (e.g. order confirmations, password resets, and notifications), Postmark is a good choice.
However, those needing more comprehensive marketing tools or operating with a tight budget at high volumes might need to consider additional solutions or providers.
Pricing
Postmark offers straightforward pricing with no hidden fees. There is a free plan at 100 emails a month and the prices scale with the number of emails you send. For example, sending 100K emails a month is $115.
Pros
- High deliverability: Focus on deliverability rates, with proactive management of sending reputations.
- Detailed tracking: Detailed insights and tracking capabilities, allowing users to monitor opens, clicks, and delivery statuses.
- Exceptional support: High-quality customer support, offering detailed and timely help when needed.
Cons
- Cost at scale: While the service is high-quality, the cost can become significant as email volumes increase, potentially making it less suitable for budget-conscious businesses.
- Feature set: While efficient, the feature set is more basic compared to some competitors who offer broader marketing and automation tools.
Summing up
In the realm of SMTP providers, Mailtrap’s focus on high deliverability rates, in-depth analytics, and safe and fast scaling makes it an ideal choice for developers. Plus, it provides generous free email limits (up to 3,500 email sends per month).
Yes, I’m bragging a bit, however, it’s not just empty promises. A team of experts works every day to bring your emails into inboxes without all the common headaches. So, get our free plan and check if we live up to your expectations.
Before we wrap up here, just a reminder that a couple of good providers didn’t make the cut here, and these include Brevo (formerly Sendinblue) and Pepipost by Netcore.
And if you’re in a regulated industry like fintech and need secure, compliant SMTP infrastructure, check our guide to SMTP providers for FinTech.
To learn which SMTP providers will dominate in 2025, make sure to check out our dedicated video:
