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Features

SMTP Relay

Drop-in SMTP relay for any application. No code changes required. Just update your mail server credentials.

SMTP that just works

Already sending email via SMTP? Point your existing application at mailkube’s relay and benefit from our infrastructure immediately, with no SDK, no API migration, and no code changes.

Configuration

SettingValue
Hostsmtp.mailkube.com
Port587 (STARTTLS) or 465 (SSL)
UsernameYour SMTP credential, as username@your-domain.com
PasswordYour SMTP credential’s secret
EncryptionSTARTTLS or SSL/TLS

Works with everything

SMTP is universal. Whether you’re running a legacy PHP app, a Django site, a Rails service, or configuring a no-code tool, if it can send email, it works with mailkube.

Full observability, no extra work

Every email sent through SMTP is tracked just like the REST API. Delivery status, bounces, opens, and clicks all appear in your dashboard the moment they happen.

Volume and performance

Our SMTP relay is backed by the same multi-region edge infrastructure as our API. High-throughput senders can use connection pooling across multiple relay endpoints to maximize throughput.

  • Connection reuse. Keep-alive connections reduce latency per message
  • Multiple endpoints. Distribute load across regional relay clusters
  • Automatic retry. Transient failures are retried transparently

Authentication and security

SMTP auth uses a dedicated SMTP credential, created per verified domain in your dashboard. The username is the credential’s username followed by the domain it is bound to, and the password is the secret shown when you create it. This is not the same as your API key, which authenticates the REST API. Connections are TLS-only. Plain-text SMTP is not supported.

What’s next