Email routing APIs: AI search visibility ranking (2026)

What we observed in this categoryauto-generated

Mailgun dominates the email routing APIs category with a visibility score of 50.0%, more than double the 25.0% held by both Amazon SES and Resend in joint second place. The category average visibility sits at just 6.2%, making Mailgun's lead especially stark. This concentration at the top means the vast majority of the 20 tracked brands receive near-zero AI exposure, and a buyer using Google AI Mode for research will encounter Mailgun in roughly half of all relevant responses.

A notable divergence appears between visibility and citation. Amazon SES and Resend both hold 25.0% visibility but carry a 0.0% citation rate, meaning Google AI Mode names them without linking to their domains. Mailgun, by contrast, pairs its 50.0% visibility with a 37.5% citation rate, making it both named and trusted as a source. Postmark and Mailtrap sit at 12.5% on both metrics, suggesting a more balanced but modest presence. Mailgun Routes is an outlier, earning 0.0% visibility yet a 37.5% citation rate.

Google AI Mode is the top engine for every brand in this category without exception. The cited sources list anchors heavily on community and video content, with youtube.com and reddit.com appearing before any vendor domains. Among vendor domains, mailgun.com and postmarkapp.com appear in the cited sources list, consistent with their citation scores. Third-party aggregators such as api.market and agentmail.to also feature, indicating AI responses draw on comparison and directory content rather than vendor documentation alone.