One of the most common questions we get from SureMail users is:

“Should I use an API to connect with my SMTP provider, or should I go with the traditional SMTP settings (username, password, port, etc.)?”

The short answer? If your SMTP provider supports API integration, use it. It’s the better option in most cases. But if it’s not available, you can still get the job done using direct SMTP settings.

But let’s break this down properly so you can make the best choice for your setup.

What’s the Difference?

SMTP (Simple Mail Transfer Protocol) is the standard way emails get sent from one server to another. You have two ways to connect to an SMTP provider:

1. Direct SMTP Settings – This involves entering the SMTP server details manually:
   • Hostname
   • Port
   • Username
   • Password
   • Encryption (TLS/SSL)
     
2. This method is widely supported and works with almost any email service provider.
   
3. SMTP API Integration – Instead of manually entering server details, you connect to the SMTP provider via its API. This is how SureMail integrates with services like Amazon SES, Brevo, Mailgun, SMTP2GO, and SendGrid.
   
   You simply enter an API key, and SureMail handles everything else behind the scenes.
   

So why should you care which one you use? Because while they both send emails, the how and why of each method make a big difference.

Why API-Based SMTP is the Better Choice

Whenever API-based SMTP integration is available, it’s the recommended way to go.

Here’s why:

1. More Reliable & Secure

With API-based integration, you’re not sending authentication credentials (username, password) over SMTP. Instead, you use an API key, which is more secure and less prone to unauthorized access.

Many SMTP providers also offer OAuth-based authentication, which removes the need for static credentials altogether.

If you’re concerned about security, API wins hands down.

2. Better Performance & Deliverability

API-based email sending typically performs better than direct SMTP settings because:

• Emails are processed faster with less chance of connection issues.
• Many API-based services offer auto-retries for failed emails.
• You avoid problems with ISPs or firewalls blocking SMTP ports.

For high-volume senders, API-based SMTP is way more efficient than relying on traditional SMTP connections.

3. No Worrying About SMTP Port Blocks

Some web hosts and ISPs block common SMTP ports (like 25, 465, or even 587). This means your emails might not even leave the server if you’re using direct SMTP settings.

With an API, this isn’t an issue because emails are sent over HTTP/HTTPS instead of SMTP ports. No blocked ports. No frustration.

4. Easier to Set Up & Maintain

When using API-based SMTP integration, you don’t need to manually configure SMTP settings or troubleshoot connection issues.

• No need to check if the hostname is correct.
• No worrying about SMTP authentication failures.
• No dealing with mail server timeouts.

Just grab an API key from your provider, paste it into SureMail, and you’re good to go.

When to Use Direct SMTP Settings Instead

While API-based SMTP integration is better when available, direct SMTP settings are still a solid backup option.

You should use direct SMTP settings when:

• Your SMTP provider doesn’t offer an API.
• You prefer full control over the SMTP connection.
• You’re using an internal SMTP server (like Postfix or Exim) rather than a third-party provider.

If you’re using a traditional email provider, SMTP settings are usually your only option.

Which One is Right for You?

Here’s the rule of thumb:

• If API integration is available, use it. It’s faster, more secure, and easier to maintain.
• If API isn’t available, use direct SMTP settings. It’s still reliable, but requires more manual setup and troubleshooting.

Since SureMail integrates directly with the APIs of all major SMTP providers and also offers direct SMTP settings, you’re covered either way.

Final Thoughts

Email delivery is too important to leave to chance. Choosing the right SMTP connection method can mean the difference between emails landing in inboxes vs. getting lost in the void.

If you’re using SureMail, we recommend going with API-based SMTP whenever possible. It removes the hassle, improves deliverability, and ensures your emails get sent reliably.

But if you must use the direct SMTP settings, no worries—SureMail has you covered there too.