SMTP or API? Two Ways to Send with Buzzmark

When it's time to actually send mail, you have two front doors: the classic SMTP protocol, or an HTTP API. Both deliver into the same pipeline and the same hive; the difference is in how your application hands the message over. Here's how to choose.

Sending over SMTP#

SMTP is the lingua franca of email. Nearly every language, framework, and off-the-shelf application already knows how to speak it. You point your app at the SMTP host with your credentials, and you're sending.

SMTP is the pragmatic choice when:

• You have existing code or a third-party app that already sends via SMTP. Often it's a matter of swapping the host and credentials — no rewrite.
• You're using a framework's built-in mail layer that expects an SMTP server.
• You want the simplest possible migration from another provider.

The trade-off is that SMTP is a chatty, connection-oriented protocol. It's slightly more overhead per message, and richer features get expressed through headers rather than clean fields.

Sending over the API#

An HTTP API takes a structured request — recipient, subject, body, options — and returns a structured response. It fits naturally into modern application code.

The API is the better choice when:

• You're building fresh and want a clean, structured integration.
• You want immediate, machine-readable responses — a message ID to track, or a clear error to handle in code.
• You're sending at high volume and want the efficiency of stateless HTTP requests over persistent SMTP connections.
• You want tighter control over per-message options and metadata.

They're not mutually exclusive#

Plenty of setups use both: SMTP for a legacy service that already had it wired up, and the API for newer code. Because they feed the same hive, the mail is treated identically once it's in — same reputation, same tracking settings, same delivery events in the log. The choice is purely about the integration surface, not about how the mail is handled downstream.

A simple way to decide#

If you already have working SMTP code, start there — it's the fastest path to your first send, and you can always adopt the API later. If you're writing the integration from scratch and want structured responses and finer control, go straight to the API. Either way, the message lands in the same place, and everything else in Buzzmark — hives, tracking, suppression, webhooks — works the same regardless of which door you came through.