MailerSend

Developer-friendly sending API with the most generous free tier in the category.

MailerSend is the transactional email service from the MailerLite family: a sending API with templates, inbound parsing, SMS alongside email, and a pricing model aimed at product teams that send receipts, resets and notifications rather than marketing blasts.

Why founders use it: the sibling relationship matters, the deliverability infrastructure of a company whose main business is email, at transactional prices with a generous free tier. The template editor produces clean responsive email without a designer, activity logs with per-message delivery detail make debugging concrete, and the API surface, send, schedule, bulk, webhooks, covers the product-side needs without enterprise ceremony.

A realistic setup: domain verification, API keys scoped per environment, transactional templates for the flows, webhooks recording bounces and opens into the database, suppression honored, and SMS for the two alerts that genuinely warrant a text.

Trade-offs: it is transactional-first, broadcast and marketing journeys belong to the sibling product, and the ecosystem integrations are thinner than the veterans. Compare with Postmark for support culture, Resend for the React-email DX, and Amazon SES for the volume floor on price.