Postmark

Postmark offers tiered email API plans starting at 10,000 emails per month with overage-based pricing. The Basic plan ($15/month) includes core sending and 45-day message retention, Pro ($16.50/month) adds dedicated IP support and advanced analytics, and Platform ($18/month) includes unlimited Servers and team seats. The service provides SMTP and API access, 100% uptime SLA, and no setup or per-call fees. Postmark doesn't charge for webhooks or data transfer.