Transactional ESPs
— Bring your own delivery API
Transactional + marketing send, with deliverability built in.
Generic SMTP for self-hosted or legacy mail infrastructure.
Lightning-fast transactional delivery with great inbox placement.
Developer-first email API. Modern SDKs, React Email native.
Enterprise-scale delivery with regional sending pools.
Reliable transactional + marketing send with strong analytics.
Step 01
Bring your own delivery.
Send through the transactional ESP you already trust — Resend, Postmark, Mailgun, MailerSend, Mailchimp Transactional, or plain SMTP for self-hosted and legacy infrastructure. GenieOS composes the email; your provider delivers it on your domain.
That means your sending reputation, your suppression lists and your deliverability history stay exactly where they are. Adopting GenieOS isn’t a migration — it’s a better editor and a better brain plugged into the pipes you’ve already laid.