SMTP relay

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Connection settings

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Example: Python

import smtplib
from email.message import EmailMessage

msg = EmailMessage()
msg["From"] = "hello@yourdomain.com"
msg["To"] = "user@example.com"
msg["Subject"] = "Welcome"
msg.set_content("Thanks for signing up.")

with smtplib.SMTP("smtp.sendflit.com", 587) as smtp:
    smtp.starttls()
    smtp.login("sendflit", "re_...")
    smtp.send_message(msg)

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How delivery works

• Each recipient in To, Cc, and Bcc gets their own copy, sent through POST /v1/emails/batch.
• The relay sets an idempotency key from each message, so a client that retries after a timeout doesn’t send duplicates.
• Temporary problems, such as a rate limit or an outage, return a 4xx SMTP reply, so your client retries later.
• Permanent problems, such as an unverified domain or a suppressed recipient, return a 5xx reply and aren’t retried.