SendHQ is an email API for developers, with one feature aimed squarely at AI products: every product, service or agent can have its own inbox and sending identity. Beyond that it covers the transactional email basics, namely sending and receiving through an API, verifying domains, tracking delivery and bounces, routing inbound mail, and issuing scoped API keys so a single agent's credentials cannot touch everything. Starter costs $9 a month for 10,000 emails across 15 verified domains, and Scale $29 for unlimited email and 200 domains. Marketing plans cost $10 a month more with the same limits. There is no free tier, and the site states a reputation rule plainly: accounts whose bounce or complaint rate stays high are restricted, which protects deliverability for everyone on the platform.
Mails.ai
4.0Email infrastructure built for AI agents – every inbound message arrives scored for prompt injection and sender reputation.



