Operator Notes
5 min readWhat is Flowmails?
A Cloudflare-native email routing platform that keeps your inbox and outbox in your own D1, with a REST API on top.
Self-hosted · CFFlowmails
Runtime v0.1
Journal
Operator notes on Cloudflare-native email.
Long-form writing about self-hosted email in D1, Workers-native routing, the REST API, and the parts of the platform that show up in the security review.
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Tutorial
6 min readHow to send transactional email from your Cloudflare custom domain
Why most transactional-email providers are overkill for a Cloudflare-native team, and how Cloudflare Email Services + a Worker gets you there in a day.
Deep Dive
8 min readHow Workers-native email routing actually processes your inbound mail
A tour of the runtime: Email Routing, the Worker, the R2 bucket for attachments, and the D1 tables behind a single inbound message.
Deep Dive
13 min readCloudflare Workers email cost — Workers + Email Services + D1 + R2
Cloudflare's email path runs through four primitives that each bill separately. Here's how Workers per-request, Email Services per-email, D1 read/write/storage, and R2 storage / operations stack up — and how to keep the bill predictable.
Tutorial
10 min readEmail webhook on Cloudflare Workers — HMAC, retries, idempotency
Receive email events in a Cloudflare Worker: HMAC-SHA256 signature verification, retry schedule, idempotency key (SMTP Message-ID), and the failure modes that catch teams out.