Looking for a Postmark alternative that's transactional-only and self-hosted?
Self-hosted on Cloudflare with no separate transactional / broadcast split. Postmark's two-product split is great when you need it; Flowmails is the single-product alternative when you don't.
Postmark is a great product — it's where most teams land the first time they need transactional email that "just works." But as your stack matures, the calculus often shifts: data residency requirements, predictable cost at higher volumes, and the desire to keep the email control plane on the same host as the rest of your infrastructure.
Flowmails is what you ship when those are the things you've started to care about. It runs on Cloudflare — the same one your Workers, R2 buckets, and Pages deployments already live in — and stores your inbox, outbox, and routing rules in your own D1. There is no per-email fee on top of Cloudflare's own pricing; the platform subscription is what you see on the /price page.
Postmark's free tier is 100 emails/month; paid starts at $15 / month for 10,000 emails, with separate pricing for broadcast. Flowmails Base is $0; Pro is $9.9 / month.
Postmark is hosted — sign up, verify sender signature, call the API. Flowmails deploys into your Cloudflare account.
Postmark: teams that want a hosted ESP with both transactional and broadcast under the same account. Flowmails: teams that don't need broadcast or want it handled by a separate tool.
Postmark exposes an HTTP API and an SMTP relay. Flowmails is REST-only. SDK-wise, the surface areas are similar (send / receive / templates / stats).
Highlights
What Flowmails does differently
Data residency
Your D1 in your Cloudflare account
Inbound parse
Yes
Broadcast / newsletters
No (transactional only)
Templates
Plain HTML / text in your Worker or dashboard
SMTP relay
No
Per-email pricing
No
Migration
How to migrate from Postmark to Flowmails
Confirm you only need transactional email
If your team uses Postmark's broadcast product for newsletters, keep it — Flowmails doesn't replace it. The migration only covers the transactional surface.
Move the domain to Cloudflare
Same prerequisite: the zone must be on Cloudflare. Flowmails provisions Email Routing + Email Services on the zone.
Port templates and SDK calls
Postmark templates use the `{{variable}}` Mustache-style syntax — port them to either plain HTML in your Worker or a templating layer of your choice. SDK calls swap to Flowmails SDK calls.
FAQ
Common questions about switching from Postmark
Other alternatives