Included on every plan — even Free
An SMTP relay for everything that can't speak REST
WordPress, ERPs, cron jobs, twenty-year-old internal tools — if it has SMTP settings, it can send authenticated, tracked, logged email through Sendibl. No code changes.
Host smtp.sendibl.com Port 23990 Security STARTTLS (required) Username sendibl Password sb_your_api_key
Works with what you already run
WordPress
any SMTP plugin — point it at the relay and contact forms stop vanishing
Nodemailer
the standard Node.js transport, four lines of config
Django & Rails
EMAIL_BACKEND / ActionMailer settings, nothing custom
PHPMailer
the workhorse behind half the PHP ecosystem
Cron jobs & monitoring
anything that can shell out to sendmail-style delivery
ERPs & legacy tools
if it has SMTP settings, it can send through Sendibl
Not a dumb pipe
Most SMTP relays are black boxes: mail goes in, and you hope. Sendibl's relay feeds the same pipeline as the REST API — your from-domain must be verified, suppressed addresses are skipped, opens and clicks are tracked, webhooks fire, and every message lands in the email log with full event history. When a WordPress plugin misbehaves at 2am, the log tells you exactly what it sent and what happened to it. You can even point a tool at our simulator addresses to verify its SMTP config without emailing anyone real.
SMTP questions
Why port 23990 instead of 25 or 587?
The relay runs behind a TCP proxy on a non-standard port. Every mainstream tool lets you set a custom port, and the unusual number sidesteps networks that block outbound 25 wholesale.
Is TLS required?
Yes — the relay refuses authentication until the connection is upgraded with STARTTLS (plaintext auth gets a 538). Most tools do this automatically when you enable TLS in their SMTP settings.
Do SMTP sends show up in the dashboard?
Yes. Relayed mail goes through the exact same pipeline as the REST API: domain verification, suppression checks, open/click tracking, webhooks, and the email log — each message tagged source: smtp.
Is SMTP extra?
No. The relay is included on every plan, including Free. SMTP sends count toward the same monthly volume as API sends.
What are the credentials?
Username is anything (sendiblby convention — it's ignored); the password is a Sendibl API key. Use a dedicated key per tool so you can revoke it independently.
Point your tool at the relay
Free plan, no credit card. Your first send takes about five minutes.
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