--- title: REST API description: The REST API allows you to send emails from any application using standard HTTP requests. Use it from any backend, serverless function, or CI/CD pipeline — no Cloudflare Workers binding is required. image: https://developers.cloudflare.com/dev-products-preview.png --- [Skip to content](#%5Ftop) Was this helpful? YesNo [ Edit page ](https://github.com/cloudflare/cloudflare-docs/edit/production/src/content/docs/email-service/api/send-emails/rest-api.mdx) [ Report issue ](https://github.com/cloudflare/cloudflare-docs/issues/new/choose) Copy page # REST API The REST API allows you to send emails from any application using standard HTTP requests. Use it from any backend, serverless function, or CI/CD pipeline — no Cloudflare Workers binding is required. For the full OpenAPI specification, refer to the [Email Sending API reference ↗](https://developers.cloudflare.com/api/resources/email%5Fsending/methods/send). ## Endpoint ``` POST https://api.cloudflare.com/client/v4/accounts/{account_id}/email/sending/send ``` ## Authentication Authenticate with a [Cloudflare API token](https://developers.cloudflare.com/fundamentals/api/get-started/create-token/) that has permission to send emails. Include it in the `Authorization` header: ``` Authorization: Bearer ``` ## Send an email * [ Simple email ](#tab-panel-6809) * [ Multiple recipients ](#tab-panel-6810) * [ With CC and BCC ](#tab-panel-6811) Terminal window ``` curl "https://api.cloudflare.com/client/v4/accounts/{account_id}/email/sending/send" \ --header "Authorization: Bearer " \ --header "Content-Type: application/json" \ --data '{ "to": "recipient@example.com", "from": "welcome@yourdomain.com", "subject": "Welcome to our service!", "html": "

Welcome!

Thanks for signing up.

", "text": "Welcome! Thanks for signing up." }' ``` Explain Code Terminal window ``` curl "https://api.cloudflare.com/client/v4/accounts/{account_id}/email/sending/send" \ --header "Authorization: Bearer " \ --header "Content-Type: application/json" \ --data '{ "to": ["user1@example.com", "user2@example.com"], "from": { "address": "newsletter@yourdomain.com", "name": "Newsletter Team" }, "subject": "Monthly Newsletter", "html": "

This month'\''s updates

", "text": "This month'\''s updates" }' ``` Explain Code Terminal window ``` curl "https://api.cloudflare.com/client/v4/accounts/{account_id}/email/sending/send" \ --header "Authorization: Bearer " \ --header "Content-Type: application/json" \ --data '{ "to": "customer@example.com", "cc": ["manager@company.com"], "bcc": ["archive@company.com"], "from": "orders@yourdomain.com", "reply_to": "support@yourdomain.com", "subject": "Order Confirmation #12345", "html": "

Your order is confirmed

", "text": "Your order is confirmed" }' ``` Explain Code ## Attachments Send files by including base64-encoded content in the `attachments` array: Terminal window ``` curl "https://api.cloudflare.com/client/v4/accounts/{account_id}/email/sending/send" \ --header "Authorization: Bearer " \ --header "Content-Type: application/json" \ --data '{ "to": "customer@example.com", "from": "invoices@yourdomain.com", "subject": "Your Invoice", "html": "

Invoice attached

Please find your invoice attached.

", "attachments": [ { "content": "JVBERi0xLjQKJeLjz9MK...", "filename": "invoice-12345.pdf", "type": "application/pdf", "disposition": "attachment" } ] }' ``` Explain Code ## Custom headers Set custom headers for threading, list management, or tracking. Refer to the [email headers reference](https://developers.cloudflare.com/email-service/reference/headers/) for the full list of allowed headers. Terminal window ``` curl "https://api.cloudflare.com/client/v4/accounts/{account_id}/email/sending/send" \ --header "Authorization: Bearer " \ --header "Content-Type: application/json" \ --data '{ "to": "user@example.com", "from": "notifications@yourdomain.com", "subject": "Your weekly digest", "html": "

Weekly Digest

", "headers": { "List-Unsubscribe": "", "List-Unsubscribe-Post": "List-Unsubscribe=One-Click", "X-Campaign-ID": "weekly-digest-2026-03" } }' ``` Explain Code ## Response A successful response returns the delivery status for each recipient: ``` { "success": true, "errors": [], "messages": [], "result": { "delivered": ["recipient@example.com"], "permanent_bounces": [], "queued": [] } } ``` Explain Code * `delivered` \- Email addresses to which the message was delivered immediately * `permanent_bounces` \- Email addresses that permanently bounced * `queued` \- Email addresses for which delivery was queued for later ## Error handling The REST API returns standard Cloudflare API error responses. A failed request returns an `errors` array with numeric error codes and machine-readable messages: ``` { "success": false, "errors": [ { "code": 10001, "message": "email.sending.error.invalid_request_schema" } ], "messages": [], "result": null } ``` Explain Code Common REST API error codes: | HTTP Status | Code | Message | Description | | ----------- | ----- | --------------------------------------------- | -------------------------------------- | | 400 | 10001 | email.sending.error.invalid\_request\_schema | Invalid request format | | 400 | 10200 | email.sending.error.email.invalid | Invalid email content | | 400 | 10201 | email.sending.error.email.no\_content\_length | Missing content length | | 400 | 10202 | email.sending.error.email.too\_big | Email exceeds size limit | | 403 | 10203 | email.sending.error.email.sending\_disabled | Sending disabled for this zone/account | | 429 | 10004 | email.sending.error.throttled | Rate limit exceeded | | 500 | 10002 | email.sending.error.internal\_server | Internal server error | Workers binding vs REST API errors The REST API returns standard Cloudflare API numeric error codes, while the [Workers binding](https://developers.cloudflare.com/email-service/api/send-emails/workers-api/) throws errors with string codes (for example, `E_SENDER_NOT_VERIFIED`). Refer to the [Workers API error codes table](https://developers.cloudflare.com/email-service/api/send-emails/workers-api/#error-codes) for the string error codes. ## Next steps * Refer to the [Email Sending API reference ↗](https://developers.cloudflare.com/api/resources/email%5Fsending/methods/send) for the full request and response schemas. * See the [Workers API](https://developers.cloudflare.com/email-service/api/send-emails/workers-api/) for sending emails directly from Cloudflare Workers using bindings. * Review [email headers](https://developers.cloudflare.com/email-service/reference/headers/) for threading, list management, and custom tracking headers. ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/email-service/","name":"Email Service"}},{"@type":"ListItem","position":3,"item":{"@id":"/email-service/api/","name":"API reference"}},{"@type":"ListItem","position":4,"item":{"@id":"/email-service/api/send-emails/","name":"Send emails"}},{"@type":"ListItem","position":5,"item":{"@id":"/email-service/api/send-emails/rest-api/","name":"REST API"}}]} ```