SMTP Relay

For frameworks and platforms that can’t easily call our REST API, use the SMTP relay. Same DKIM signing, suppression, billing, and webhook delivery — your app just speaks plain SMTP.

Connection

TLS is required. Plain-text auth is rejected.

Test with swaks

swaks --to [email protected] \
      --from [email protected] \
      --server smtp.splashifypro.com \
      --port 587 -tls \
      --auth-user emailapikey \
      --auth-password "$SPLASHIFY_API_KEY" \
      --header "Subject: Test from swaks" \
      --body "Hello"

WordPress (WP Mail SMTP)

1. Plugin → WP Mail SMTP → install
2. Mailer → Other SMTP
3. Host: smtp.splashifypro.com · Port: 587 · Encryption: TLS
4. Auth: ON · Username: emailapikey · Password: your API key
5. Save & send a test email

Django

# settings.py
EMAIL_BACKEND = "django.core.mail.backends.smtp.EmailBackend"
EMAIL_HOST = "smtp.splashifypro.com"
EMAIL_PORT = 587
EMAIL_USE_TLS = True
EMAIL_HOST_USER = "emailapikey"
EMAIL_HOST_PASSWORD = os.environ["SPLASHIFY_API_KEY"]
DEFAULT_FROM_EMAIL = "[email protected]"

Laravel

MAIL_MAILER=smtp
MAIL_HOST=smtp.splashifypro.com
MAIL_PORT=587
MAIL_USERNAME=emailapikey
MAIL_PASSWORD=${SPLASHIFY_API_KEY}
MAIL_ENCRYPTION=tls
[email protected]

Node (nodemailer)

import nodemailer from "nodemailer";
 
const transport = nodemailer.createTransport({
  host: "smtp.splashifypro.com",
  port: 587,
  secure: false,                    // STARTTLS
  auth: {
    user: "emailapikey",
    pass: process.env.SPLASHIFY_API_KEY,
  },
});
 
await transport.sendMail({
  from: "[email protected]",
  to: "[email protected]",
  subject: "Hello",
  html: "<p>Welcome</p>",
});

Postfix

In /etc/postfix/main.cf:

relayhost = [smtp.splashifypro.com]:587
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_use_tls = yes
smtp_tls_security_level = encrypt

In /etc/postfix/sasl_passwd:

[smtp.splashifypro.com]:587 emailapikey:pk_live_...

postmap /etc/postfix/sasl_passwd
chmod 600 /etc/postfix/sasl_passwd*
postfix reload

Supabase Auth (transactional email for signups, OTPs, password reset)

Supabase ships a “Custom SMTP” panel that you can point at the relay so signup confirmation, magic-link, and password-recovery emails come from your verified sender instead of the Supabase default.

Project → Project Settings → Auth → SMTP Settings:

Then save & hit Send test email. If you get 535 5.0.0 5.7.0 invalid api key format it means you pasted something other than a pk_live_… (or sk_live_… for app-developer accounts) key — copy the key from Settings → API key  on the partner dashboard.

Things to know

• Sender must be on a verified identity. Sends from an unverified email/domain are rejected with 550 5.7.1 sender '<addr>' is not on a verified identity for this partner. Add the domain or email at Settings → Identities  before testing.
• Suppression list applies. Recipients on your account suppression list are rejected at RCPT TO with 550 5.7.1 recipient on suppression list.
• Free sandbox: 200 emails/day. New accounts are sandboxed. Once you exceed the 200/day quota you’ll get 452 4.7.0 sandbox daily quota of 200 emails reached. Request production access from the dashboard to lift it.
• Billing. ₹0.01/email for paid sends (post-sandbox); sandbox sends are free. SMTP and REST sends bill identically.
• Webhooks fire normally. SMTP and REST sends produce the same event stream into your configured destinations.
• TLS is required. Plain-text AUTH is rejected; the relay only advertises AUTH after STARTTLS (port 587) or on the implicit-TLS port (465).
• Per-message metadata via headers. Set X-Configuration-Set: <name> on the outbound message to attribute the send to a config set.