Send raw

Send a fully-formed MIME message (RFC 5322). For when you need control over headers, attachments, multipart structure, or DKIM-signed forwarding. Equivalent to AWS SES SendRawEmail.

POST

/api/v1/partner/email/send-raw

Request body

{
  "raw_message_base64": "RnJvbTogaGVsbG9AeW91cmNvbXBhbnkuY29tDQpUbzogY3VzdG9tZXJAZXhhbXBsZS5jb20NClN1YmplY3Q6IEhlbGxvDQpDb250ZW50LVR5cGU6IHRleHQvcGxhaW47IGNoYXJzZXQ9dXRmLTgNCg0KSGVsbG8h",
  "configuration_set_name": "production"
}

Field	Type	Required	Notes
`raw_message_base64`	string	yes	base64-encoded RFC 5322 message. Max 10 MB decoded.
`from`	string	no	Override From-address parsing. Defaults to parsing the message's `From:` header
`to`	string[]	no	Override recipient parsing. Defaults to parsing `To:` header
`configuration_set_name`	string	no
`customer_id`	string	no
`category`	string	no
`tags`	object	no

What you control

All headers — From, To, Cc, Bcc, Subject, Reply-To, Message-ID, arbitrary X- headers, In-Reply-To, References
MIME structure — multipart/alternative, multipart/mixed, multipart/related (inline images via Content-ID:)
Attachments — encode each part with the right Content-Type + Content-Disposition + Content-Transfer-Encoding
Custom headers — anything not on the reserved list

What we override

Date: — set to send time if missing
Message-ID: — added if missing
DKIM-Signature — we always sign with our shared key
Return-Path — set to our bounce address for VERP routing

When to use this

Sending forwarded mail with original headers preserved
Replying inside an existing thread (In-Reply-To / References)
Multipart with attachments
Custom List-Id / List-Help / List-Subscribe / List-Unsubscribe headers

For simple HTML+text sends, use /send — much less ceremony.

Example

Building a multipart message in Node:

import { createMimeMessage } from "mimetext";

const msg = createMimeMessage();
msg.setSender("[email protected]");
msg.setRecipient("[email protected]");
msg.setSubject("Receipt + invoice attached");
msg.addMessage({ contentType: "text/plain", data: "See attached." });
msg.addMessage({ contentType: "text/html", data: "<p>See attached.</p>" });
msg.addAttachment({
  filename: "invoice.pdf",
  contentType: "application/pdf",
  data: pdfBase64,
});

const raw = msg.asEncoded();
const rawB64 = Buffer.from(raw).toString("base64");

await fetch("https://api.splashifypro.com/api/v1/partner/email/send-raw", {
  method: "POST",
  headers: { Authorization: `Bearer ${API_KEY}` },
  body: JSON.stringify({ raw_message_base64: rawB64 }),
});