Docs Sending domains

Sending domains

Verify SPF, DKIM, DMARC, and ownership TXT without moving MX.

Guide 02

Format HTTPS JSON

A sending domain is the domain in your from address. ResenderMail will not send until that domain is verified.

What you publish

The dashboard gives you exact records. You add them at your DNS host:

Ownership TXT — proves you control the domain
SPF — includes ResenderMail as an allowed sender
DKIM — a public key so inboxes can verify signatures
DMARC — a policy for unauthenticated mail from your domain

Do not change MX unless you intend to move inbound mail. Inbound mailboxes are not part of this service.

After DNS propagates

The dashboard re-checks the records. When they match, the domain is verified and you can create an API key scoped to it.

One key, one domain

Each API key can only send from its verified domain. Add another domain if you need another from namespace.

Example request

Live request shape

POST /api/v1/emails

curl -X POST https://api.resendermail.com/api/v1/emails \
  -H "X-API-Key: ep_live_..." \
  -H "Content-Type: application/json" \
  -d '{
    "from": "hello@yourdomain.com",
    "to": ["customer@example.com"],
    "subject": "Hello from ResenderMail",
    "html": "<p>Hello</p>"
  }'

const res = await fetch(
  "https://api.resendermail.com/api/v1/emails",
  {
    method: "POST",
    headers: {
      "X-API-Key": "ep_live_...",
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      from: "hello@yourdomain.com",
      to: ["customer@example.com"],
      subject: "Hello from ResenderMail",
      html: "<p>Hello</p>",
    }),
  }
);
const { id, status } = await res.json();

import requests

resp = requests.post(
    "https://api.resendermail.com/api/v1/emails",
    headers={
        "X-API-Key": "ep_live_...",
        "Content-Type": "application/json",
    },
    json={
        "from": "hello@yourdomain.com",
        "to": ["customer@example.com"],
        "subject": "Hello from ResenderMail",
        "html": "<p>Hello</p>",
    },
)
data = resp.json()

using var client = new HttpClient();
client.DefaultRequestHeaders.Add("X-API-Key", "ep_live_...");

using var content = new StringContent(
    """{"from":"hello@yourdomain.com","to":["customer@example.com"],"subject":"Hello from ResenderMail","html":"<p>Hello</p>"}""",
    Encoding.UTF8,
    "application/json"
);
var res = await client.PostAsync(
    "https://api.resendermail.com/api/v1/emails",
    content
);

var client = HttpClient.newHttpClient();
var req = HttpRequest.newBuilder()
    .uri(URI.create("https://api.resendermail.com/api/v1/emails"))
    .header("X-API-Key", "ep_live_...")
    .header("Content-Type", "application/json")
    .POST(HttpRequest.BodyPublishers.ofString("""
        {"from":"hello@yourdomain.com","to":["customer@example.com"],"subject":"Hello from ResenderMail","html":"<p>Hello</p>"}
        """))
    .build();
var res = client.send(req, HttpResponse.BodyHandlers.ofString());

payload := strings.NewReader("{\"from\":\"hello@yourdomain.com\",\"to\":[\"customer@example.com\"],\"subject\":\"Hello from ResenderMail\",\"html\":\"<p>Hello</p>\"}")
req, err := http.NewRequest(http.MethodPost, "https://api.resendermail.com/api/v1/emails", payload)
if err != nil {
    log.Fatal(err)
}
req.Header.Set("X-API-Key", "ep_live_...")
req.Header.Set("Content-Type", "application/json")
res, err := http.DefaultClient.Do(req)

Example response

Response shape

200 api.resendermail.com

{
  "id": "em_4f2c…",
  "status": "queued"
}

Reference

Auth X-API-Key
Format application/json
Base URL https://api.resendermail.com