SMTP or API? Which solution is best for my business?

Natalia Zacholska, 9 September 2021

EmailLabs is committed to providing its customers with the most tailored solution, so it offers email sending through both SMTP and API integration. Which of these options is best for your business? The answer to this question is complex and largely depends on the resources available and your requirements in terms of volume. So in this blog post, we’ll look at the characteristics of both SMTP and API, focusing on their features.

Definition of SMTP

SMTP (Simple Mail Transfer Protocol) is a communication protocol designed to send email using a set of commands that authenticate and direct the transmission of email. SMTP provides a mechanism for transferring messages directly from the sending server to ultimate recipient , or through a number of intermediate relay or getaway hosts on its path .

Definition of API

API is an application programming interface, made out of a set of rules by which computer programs can share data between the two. In other words, an API defines how applications can communicate with each other. With an e-mail API, an online store website can automatically send both transactional and marketing messages in response for specific events. Moreover , API integration also allows using templates and gives access to various types of data and statistics .

API or SMTP: what to choose?

The choice of integration method is not always dictated by the type of messages sent, but the customer’s needs or technical possibilities. API grants additional capabilities not offered by other protocols like SMTP. but requires knowledge or technical background. On the other hand, as developers admit, working with this interface is highly intuitive because it is more common and has a wider application (e.g. Google Maps).

SMTP offers default integration from e.g. email sending platforms, marketing automation programs, online stores (PrestaShop, WooCommerce etc.) or the popular WordPress. As a result, adding a new integration is reduced to a few basic steps that do not require programming knowledge.

API makes it easy to send emails, especially transactional ones, from within your app or website. Our customer made a purchase? Let’s send him a confirmation email. When an order is submitted, let’s automatically add a tracking number. What’s more, the email API also gives easy access to a lot of data such as messages statuses. So, if you handle high-volume marketing or transactional mailings daily and need advanced options at the same time, it’s worth choosing integration via API.

The SMTP protocol is a universal standard that is often used for sending transactional or marketing messages. Even though it offers fewer options, this solution provides great control over mailings, while allowing faster integration with e.g. CRM systems. As a result, it’s a good solution for senders who send fewer emails and expect simple integration and maintenance.

API vs SMTP: the key differences


    • Requires more programming background
    • Faster email delivery, especially for large volumes
    • Access to more detailed data
    • Ability to use templates
    • Simultaneous sending of emails up to 200 recipients at once
    • Ability to pull logs to store them on your side


    • Lesser requirements to the IT background (in case of ready-made solutions such as stores or CRM platforms, easy integration, which consists only in entering the access data to the account)

API vs SMTP: summary

To provide the highest possible flexibility to its customers, EmailLabs offers both SMTP and API integration. As a result, each company can choose the solution that best fits their individual requirements, available resources, and business goals. Thus, regardless of whether we have a store, billing, accounting, CRM, ERP, CMS or dedicated Marketing Automation system – in each of the above , the implementation of sending via SMTP will take only a moment. On the other hand, API supports the REST standard that enables full integration with your IT systems, offering quick connections to EmailLabs infrastructure and the possibility of collecting the necessary data (in retention period) with no need to log into the control panel.

Want to learn more about the differences between API and SMTP? Contact us and EmailLabs specialists will be happy to answer any of your questions and recommend which solution is best for your company.

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