cloudflare-email-service

Cloudflare Email Service

Your knowledge of the Cloudflare Email Service, Email Routing or Email Sending may be outdated. Prefer retrieval over pre-training for any Cloudflare Email Service task.

Cloudflare Email Service lets you send transactional emails and route incoming emails, all within the Cloudflare platform. Your knowledge of this product may be outdated — it launched in 2025 and is evolving rapidly. Prefer retrieval over pre-training for any Email Service task.

If there is any discrepancy between this skill and the sources below, always trust the original source. The Cloudflare docs, REST API spec, @cloudflare/workers-types, and Agents SDK repo are the source of truth. This skill is a convenience guide — it may lag behind the latest changes. When in doubt, retrieve from the sources below and use what they say.

Retrieval Sources

Source	How to retrieve	Use for
Cloudflare docs	Cloudflare MCP docs tool or URL https://developers.cloudflare.com/email-service/	API reference, limits, pricing, latest features
REST API spec	https://developers.cloudflare.com/api/resources/email_sending	OpenAPI spec for the Email Sending REST API
Workers types	https://www.npmjs.com/package/@cloudflare/workers-types	Type signatures, binding shapes
Agents SDK docs	Email agent walkthrough	Email handling in Agents SDK

FIRST: Check Prerequisites

Before writing any email code, verify the basics are in place:

1. Domain onboarded? Run npx wrangler email sending list to see which domains have email sending enabled. If the domain isn't listed, run npx wrangler email sending enable userdomain.com or see cli-and-mcp.md for full setup instructions.
2. Binding configured? Look for send_email in wrangler.jsonc (for Workers)
3. postal-mime installed? Run npm ls postal-mime (only needed for receiving/parsing emails)

What Do You Need?

Start here. Find your situation, then follow the link for full details.

I want to...	Path	Reference
Send emails from a Cloudflare Worker	Workers binding (no API keys needed)	sending.md
Send emails from an AI agent built with Cloudflare Agents SDK	onEmail() + replyToEmail() in Agent class	sending.md
Send emails from an external app or agent (Node.js, Go, Python, etc.)	REST API with Bearer token	rest-api.md
Send emails from a coding agent (Claude Code, Cursor, Copilot, etc.)	MCP tools, wrangler CLI, or REST API	cli-and-mcp.md
Receive and process incoming emails (Email Routing)	Workers email() handler	routing.md
Set up Email Sending or Email Routing	wrangler email sending enable / wrangler email routing enable, or Dashboard	cli-and-mcp.md
Improve deliverability, avoid spam folders	Authentication, content, compliance	deliverability.md

Sending Workflow

Prefer the binding for Workers; use REST for external apps or when explicitly requested. Read sending.md or rest-api.md to retrieve the documentation for the selected task before writing code. These guides cover setup, recipients, attachments, headers, limits, response handling, and errors; the Workers guide also covers Agents SDK integration and types matched to the project configuration.

Common Mistakes

Mistake	Why It Happens	Fix
Forgetting send_email binding in wrangler config	Email Service uses a binding, not an API key	Add "send_email": [{ "name": "EMAIL" }] to wrangler.jsonc
Sending from an unverified domain	Domain must be onboarded onto Email Sending before first send	Run wrangler email sending enable yourdomain.com or onboard in Dashboard
Reading message.raw twice in email handler	The raw stream is single-use — second read returns empty	Buffer first: const raw = await new Response(message.raw).arrayBuffer()
Missing text field (HTML only)	Some email clients only show plain text; also helps spam scores	Always include both html and text versions
Using email for marketing/bulk sends	Email Service is for transactional email only	Use a dedicated marketing email platform for newsletters and campaigns
Forwarding to unverified destinations	message.forward() only works with verified addresses	Run wrangler email routing addresses create user@gmail.com or add in Dashboard
Testing with fake addresses	Bounces from non-existent addresses hurt sender reputation	Use real addresses you control during development
Hardcoding API tokens in source code	Tokens in code get committed and leaked	Use environment variables or Cloudflare secrets
Ignoring the from domain requirement	The from address must use a domain onboarded to Email Service	Verify the domain first, then send from anything@that-domain.com
Using email key in REST API from object	REST API uses address not email for from object	Use { "address": "...", "name": "..." } for REST, { "email": "...", "name": "..." } for Workers
Using replyTo in REST API	REST API uses snake_case field names	Use reply_to for REST API, replyTo for Workers binding

References

Read the reference that matches your situation. You don't need all of them.

• references/sending.md — Documentation map for Workers binding, attachments, and Agents SDK email.
• references/rest-api.md — Documentation map for HTTP sending, request schemas, responses, and errors.
• references/routing.md — Inbound email() handler, forwarding, replying, parsing. For receiving emails.
• references/cli-and-mcp.md — Domain setup, wrangler commands, MCP tools. For first-time setup.
• references/deliverability.md — SPF/DKIM/DMARC, bounces, suppressions, best practices.