Startups and marketers need to reliably scale their marketing emails to do well in this competitive digital landscape. Especially in 2025, when the digital war is going on all around. To ensure a good deliverability rate, it is important to invest in the right SMTP server.
Mailchimp and Sendinblue are two of the popular email marketing platforms that marketers and startups can use. However, budget can be one of the factors that could restrain startups from using such costly SMTP servers.
Well, don’t worry. This is where the concept of free SMTP servers comes in. Startups and marketers can leverage these servers during their initial stage and later shift to more robust platforms.
Now, when it comes to the word “free,” you might be thinking about unreliable servers. However, this is not the case. In this post, we are going to talk about some of the top free SMTP servers that are as reliable and efficient as Mailchimp and Sendinblue, but with certain restrictions.
Let us have a look at these servers.
Top 7 Free SMTP Servers for Startups and Marketers in 2025
1. SendGrid
If we talk about the free plan of SendGrid, it lets you send 100 emails per day for free. It won’t be wrong to say that it has been a go-to SMTP for startups for years. If you are looking to start with a small email volume, SendGrid’s free plan is ideal for you.
Not only this, but it also allows you to test campaigns to ensure their efficiency. Plus, its APIs make integration smooth whether you’re using a CRM, WordPress, or a custom app. Above all, with SendGrid, you can scale later smoothly as per your requirements.
Key Features
- High deliverability
- Real-time analytics
- Robust APIs and SMTP relay
2. Mailgun
Just like SendGrid, Mailgun also allows businesses to send 100 emails per day with its free plan. This platform is known to be a developer-friendly platform that is best for sending transactional emails.
Another advantageous feature of Mailgun is that it is easy to set up. It is an AI-powered platform that will give you a competitive edge to scale your business and achieve good results. If you are running a SaaS product, it could be a great option for you.
Key Features
- Detailed logs
- API-first approach
- Advanced analytics
3. Brevo (Formerly Sendinblue)
One of the advantageous features of Brevo is that it allows marketers to send 300 emails per day with its free plan. Additionally, startups can leverage customizable email templates and a drag & drop editor to ensure a user-friendly interface.
It also lets marketers have limited access to marketing automation tools. Additionally, Brevo’s free plan also includes SMTP relay. If you want to test newsletters and transactional emails, Sendinblue can be the ideal choice.
Key Features
- User-friendly interface
- Basic email marketing features
- SMTP relay for transactional emails
4. Mailjet
The free plan of Mailjet includes 200 emails per day, a good volume for startups. It offers a simple SMTP server with decent analytics and a straightforward dashboard.
It’s easy to get started if you want something that “just works.” If you are looking to send both marketing and transactional emails with a small team, Mailjet is the SMTP you can count on.
Key Features
- Real-time collaboration for email campaigns
- Decent deliverability
- Easy API integrations
5. Postmark
Another reliable SMTP server that offers a decent free plan is Postmark. You can send 100 emails per day with its free plan. Postmark is known for fast and reliable transactional email delivery.
While its free tier is mainly for testing (not production), it’s great for developers to validate email flows. If you decide to go paid, Postmark’s speed and deliverability are top-notch.
Key Features
- Exceptional speed
- Focus on transactional emails
- Great logs and analytics
6. Mailtrap
The free plan of Mailtrap supports sending 1000 emails per month. This platform is best for testing and staging. If you are looking to test your emails and debug before going live, Mailtrap is the ideal choice. Hence, it is a suitable platform for QA teams and developers.
Key Features
- Safe testing environment
- Email previews and spam checks
- No risk of spamming real users
7. SMTP2GO
You can send 200 emails per day using SMTP2GO. It is a reliable SMTP service with a generous free tier. It’s built for businesses that want reliable sending and easy integration without breaking the bank.
If you are a small business and looking for a reliable SMTP server with a global reach, SMTP2GO could be the best choice.
Key Features
- Global server network
- Real-time analytics
- Easy setup for apps and websites
How to Choose the Right Free SMTP Server?
Not all SMTP servers are created equal. Here’s what to consider:
- Email volume: Match the free tier’s daily or monthly limit with your sending needs.
- Ease of use: Do you need a user-friendly dashboard or are you comfortable with APIs?
- Deliverability: Some free SMTP servers have better reputations with ISPs, helping you stay out of spam folders.
- Scalability: Pick a service that grows with you. Starting free is great, but upgrading should be smooth too.
- Integration: Make sure the SMTP server works with your current website, app, or marketing platform.
Tips to Get the Most Out of Free SMTP Servers
- Warm up your IP: If you’re sending from a new domain, start slow to build your sender reputation.
- Authenticate your domain: Set up SPF, DKIM, and DMARC records to prove you’re a legit sender.
- Track your emails: Most free plans include basic analytics. Use them to tweak your strategy.
- Stay compliant: Even if it’s free, you’re still on the hook for GDPR, CAN-SPAM, and other email laws.
Final Thoughts
A good SMTP server can make the difference between emails that land in inboxes and emails that vanish into the spam folder. The free options above are all solid choices in 2025, and they’re perfect for startups and marketers who need to get the ball rolling without extra costs.
Whether you’re sending product updates, newsletters, or transactional emails, the right SMTP server can support your growth. Start with a free plan that matches your needs and upgrade as your audience grows. With the right foundation, you’ll be well on your way to email success in 2025.
