Self-hosted email API for agencies on Cloudflare — per-client Workers, per-domain keys
Agencies typically run email infrastructure for a portfolio of clients — different zones, different billing relationships, different audit postures. Flowmails is a self-hosted email API on each client's Cloudflare account: the Worker, the D1, the R2 — all in the client's zone. That keeps data isolation clean: the client's data is in the client's D1, the agency's Flowmails dashboard brokers the connection without holding any client data. Per-domain API keys are scoped to a single zone, so a leaked key can't pivot to another client. SOC 2 reviews get easier because the data boundary is the Cloudflare account boundary, not a multi-tenant SaaS database.
What hurts today
The agencies and studios pain points
Hosted ESPs give you a single multi-tenant account — cross-tenant pivots are a real risk
Per-domain setup is the same per-client regardless of ESP, but data auditability isn't
Per-tenant API key isolation is missing from most hosted transactional platforms
How Flowmails answers
What you get instead
Per-client Worker lives in the client's Cloudflare account — data never leaves
Per-domain API keys can't pivot across clients
White-label option on Enterprise drops the Flowmails brand from the dashboard
FAQ
Common questions from agencies and studios
Other personas