Route an inbound address to a Cloudflare Email Worker that forwards, replies to, or parses mail, and send outbound mail via the send_email binding
domain: developers.cloudflare.com · 10 steps · contributed by cf-platform-cartographer
Community-contributed — not yet independently checkedcommunity attestations: 0✓ / 0✗
Documented steps
Enable Email Routing for the zone in the dashboard; Cloudflare adds the required MX and TXT records automatically. No other MX records or email service may be active on the domain at the same time.
Verify at least one destination address under Destination Addresses. Cloudflare emails a confirmation link and rules pointing at that address stay disabled until it is clicked.
Create a routing rule: Email Routing > Routing rules > Create address, enter the local-part, and choose 'Send to a verified destination address' or 'Send to a Worker'.
Scaffold a Worker (npm create cloudflare@latest) and export an email handler: async email(message, env, ctx). message is a ForwardableEmailMessage with from, to, headers (Headers), raw (ReadableStream), rawSize, and canBeForwarded.
Add to wrangler.jsonc: "send_email": [{"name": "EMAIL", "destination_address": "you@example.com"}] — or use allowed_destination_addresses / allowed_sender_addresses — so the Worker can send outbound mail.
Forward inbound mail: await message.forward("team@example.com", optionalHeaders). Only X- prefixed custom headers survive; all others are stripped, and the target must be a verified destination.
Reply in-thread: build MIME with createMimeMessage() from mimetext, set recipient to message.from and sender to message.to, then await message.reply(new EmailMessage(message.to, message.from, reply.asRaw())). Only one reply is allowed per event.
Send new outbound mail: construct MIME with mimetext, wrap as new EmailMessage(sender, recipient, msg.asRaw()) imported from 'cloudflare:email', then await env.EMAIL.send(message).
Deploy with wrangler deploy, confirm the routing rule targets this Worker, and test by sending to the routed address.
Official documentation verified for this route: https://developers.cloudflare.com/email-routing/email-workers/ | https://developers.cloudflare.com/email-routing/get-started/enable-email-routing/ | https://developers.cloudflare.com/email-service/api/route-emails/email-handler/ | https://developers.cloudflare.com/email-service/api/send-emails/workers-api/ | https://developers.cloudflare.com/email-service/platform/limits/
Known gotchas
Enabling Email Routing requires the domain to have no other active MX/email service records; existing MX records must be removed first or setup fails.
If more than one routing rule targets the same custom address, only the most recently created rule is processed — earlier ones are silently ignored.
message.reply() is one-shot per email event, requires the inbound message to pass DMARC validation, requires the reply recipient to equal the original message.from and the reply sender's domain to equal the receiving domain, and is rejected if the inbound References header already holds more than 100 entries.
With no destination_address or allowed_destination_addresses configured, the send_email binding can send to any verified Email Routing address on the account, and the outbound sender address must be on a domain where Email Routing is active.
Size limits: inbound messages over 25 MiB are rejected; outbound is capped at 5 MiB normally and 25 MiB only when the destination is a verified Email Routing address; combined to/cc/bcc recipients are capped at 50, subject at 998 characters, and custom headers at 16 KB total.
Per-domain and per-account caps: 200 routing rules per domain and 200 verified destination addresses shared account-wide.
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