Simple Mail Service is a European email delivery service for companies, organisations and individuals that need to send transactional messages from websites and applications. Customers can connect through a REST API or SMTP relay, with a user-friendly dashboard for managing domains and API keys. The service is designed to scale and is built around infrastructure owned and operated in the European Union, rather than acting as a wrapper for another provider.

Its features include configurable retention for email metadata, data archiving to object storage, OpenID Connect single sign-on, webhooks and deliverability protection. Simple Mail Service emphasises privacy, security, European autonomy and data sovereignty, and provides a signed data processing agreement. Its hardware is hosted in redundantly distributed infrastructure at SOC 2 Type II-certified data centres; infrastructure management is handled by a Dutch managed services provider.

The service is intended to be straightforward to set up and use, with support for common application and website workflows, including sending from PHP scripts and WordPress sites.