Best 9 Transactional Email API to use in 2026

Loops is an email sending platform made for software companies. It lets you create and send three types of emails from one dashboard: campaigns (one-time announcements), loops (automated sequences), and transactional emails (password resets, receipts).

Mailjet is a complete email platform that handles both marketing campaigns and automated transactional emails. You can design emails using templates or build your own from scratch without coding. The platform includes tools for managing contacts, creating email lists, and tracking how your emails perform.

Elastic Email is an all-in-one email service that handles both marketing campaigns and transactional messages. You can use it to create beautiful newsletters, automate email sequences, and send important messages like order confirmations or password resets. The platform includes several key components.

Postmark is an email delivery service that sends your automated emails using modern technology. You can connect it to your website or app through their API or SMTP settings, and it handles the rest. Unlike regular email services, Postmark specializes in transactional emails - the important messages your customers expect right away.

SendGrid is a complete email delivery system that works in the cloud. You can use it in two ways: through an API for automatic emails from your website or app, or through a user interface for creating marketing campaigns.

MailerSend is a cloud-based email service that focuses on sending emails automatically from your apps or websites. Unlike regular email services for marketing campaigns, MailerSend specializes in sending individual messages triggered by user actions.

Maileroo is a cloud-based email service that helps you send and track emails from your website, app, or business. It works as both an SMTP service for sending regular emails like password resets and order confirmations, and as an email marketing platform for sending newsletters and campaigns.

Resend is an email API service that helps developers send emails from their applications. Think of it as the delivery system for your app's emails - whether that's password resets, welcome messages, or marketing campaigns.

Mailgun is a cloud-based email delivery service designed specifically for developers and businesses who need to send emails programmatically through their applications. Think of it as the engine that powers email functionality in websites and apps - from simple contact forms to complex automated email workflows.