Mailgun

What it does

Mailgun is a transactional email API and SMTP relay service built for developers who need to send confirmation emails, password resets, receipts, and other app-triggered messages at scale. It handles sending infrastructure, email validation, inbound routing, and delivery analytics through a REST API, SDKs for major languages, and SMTP credentials that drop into most codebases in minutes. It's owned by Sinch and used mostly by SaaS companies and app developers rather than marketing teams — it sends the emails a product generates, not the campaigns a marketing team writes.

Who this helps

• SaaS founders who need reliable transactional email without building sending infrastructure from scratch

• Developers who want API-first control over sending, templates, and webhooks

• Agencies managing multiple client apps that need one dashboard for email logs and bounce handling

• Teams already on SendGrid or Postmark comparing transactional email vendors on price and deliverability tooling