Ongage

Ongage is built for high-volume email senders who need intelligent routing across multiple email service providers. The platform automatically distributes sends across multiple ESPs to optimize for deliverability and avoid hitting rate limits on any single provider. Real-time A/B testing, advanced segmentation, and compliance management tools give enterprises fine-grained control over their email programs.

This platform makes sense for large B2B operations sending millions of emails monthly and caring deeply about inbox placement. Its multi-ESP strategy adds complexity but provides failover and ensures high delivery rates, though smaller companies or those committed to a single provider won't need its routing capabilities.