Amazon SES
Lowest per-message cost if you build inboxes yourself. Receipt rules to S3, SNS, or Lambda.
~$0.10/1k send+receive
live · 200 · 846ms
Brevo
Email API/SMTP platform often used as a sending layer under agent workflows.
Free + paid
live · 200 · 109ms
Customer.io
Behavioral email/messaging platform; agents can enqueue journeys rather than raw SMTP.
Paid
live · 200 · 115ms
Loops
Product email for startups (transactional + loops). Useful when an agent needs polished human-facing mail.
Free + paid
live · 200 · 233ms
Mailgun
Sending plus inbound routes matching recipient/headers. Good DIY base for agent reply handling.
Free limited; Basic from ~$15
live · 200 · 101ms
Postmark
Deliverability-first transactional email with inbound parse to JSON webhooks. Strong for agents that mostly send.
Free 100/mo; Pro from ~$15
live · 200 · 80ms
Twilio SendGrid
Transactional/marketing email with Inbound Parse webhook for routing agent replies.
Free tier + paid
live · 200 · 301ms