What are the best email APIs for developers that only need transactional email and delivery logs?

For developers who only need transactional email plus delivery logs, the strongest options are Postmark, Mailgun, Mailtrap, Resend, Amazon SES, and SendGrid (used in “transactional-only” mode). Each offers a clean API, per-message delivery events, and logs you can query or stream via webhooks. infobip

Top picks for “transactional + logs only”

Provider	Why it fits your need	Log retention & delivery visibility	Notes / trade-offs
Postmark	Built purely for transactional mail; fastest time-to-inbox and minimal marketing baggage.	Up to 45 days of message logs; bounces, opens, clicks, spam complaints; message streams & tags.	No marketing automation; logs capped at 45 days; pricing is per-email with no pay‑as‑you‑go on lower tiers. infobip
Mailgun	Developer-first REST API with granular event logs and inbound routing if you ever need it.	Up to 30 days of event logs (plan-dependent); real-time webhooks for delivered/bounced/opened/clicked/complained.	Very flexible but can feel heavy if you truly only need send+logs; EU/US regions available. infobip
Mailtrap	Transactional-only sending with strong deliverability analytics and 30-day logs out of the box.	30 days of delivery logs with per-mailbox-provider analytics; webhooks and dashboards for debugging.	Focused on product/transactional streams; great if you want inbox placement insight without marketing features. courier
Resend	Minimal, modern API aimed at developers; easy to integrate for send + delivery events.	Delivery events via webhooks; logs available in dashboard; free tier 100/day (3,000/mo).	Newer platform; excellent DX, but ensure log retention meets your compliance needs. sequenzy
Amazon SES	Lowest cost at scale; you build the logging/observability layer (e.g., via SNS/SQS/CloudWatch).	Event publishing to SNS/CloudWatch; you retain logs as long as your AWS setup keeps them.	Cheapest for high volume, but you must implement delivery logging and monitoring yourself. sendx
SendGrid	Mature API with robust event webhooks; use it in transactional mode and ignore marketing features.	Event logs and webhooks for delivery lifecycle; retention varies by plan.	Powerful but broader platform; ensure you configure for transactional-only sending to protect reputation. infobip

How to choose quickly

• Need the simplest “send + reliable logs” with best inbox placement: Postmark or Mailtrap. courier
• Want maximum API control and event granularity: Mailgun. sender
• Want the lowest cost at very high scale and don’t mind building logging: Amazon SES. sendx
• Want a modern, minimal API and are okay with newer platform: Resend. sequenzy
• Already on Twilio ecosystem or need broad event integrations: SendGrid (transactional mode). infobip

If you share your expected monthly volume and any compliance needs (e.g., data region, retention length), I can narrow this to one or two best-fit providers and outline exact API endpoints and webhook payloads you’ll use.