Many systems can't call an API, but almost all speak SMTP: WordPress, Shopware, WooCommerce, Magento, Nextcloud, ticketing systems, CRMs and older in-house software. Sending their mail through web hosting or an office mail server has well-known consequences: missing signatures, blocked IPs, order confirmations in spam.
ridu is an SMTP relay in Germany that authenticates, delivers and logs your email.
Credentials
| Server | smtp.ridu.ai |
| Port | 465 (TLS) or 587 (STARTTLS) |
| Username | ridu |
| Password | your API key (rd_live_…) |
Login is only possible over encrypted connections. For WordPress, any SMTP plugin with these values will do. Ideally create a separate “sending only” API key bound to one domain.
What happens to your email
- Signed: ridu adds a DKIM signature for your domain and its own return path for bounces.
- Unchanged: the message stays as your application builds it – attachments and HTML included.
- Correct Bcc: Bcc recipients come from the SMTP envelope and never appear in the headers.
- Visible: every email shows up with per-recipient status in the dashboard, including the server response.
- Clean: undeliverable addresses are suppressed automatically.
Control via headers
X-Ridu-Tags: kind=order adds tags for reporting and webhooks. Ridu-Idempotency-Key prevents duplicates when your application resubmits after a timeout.
Privacy
The server is in Falkenstein, Germany. Content is deleted after the retention period you set, and the data processing agreement is part of the account – a good fit for shops and practices sending sensitive data.