Transactional email APIs

The default backbone for transactional email at scale. Lowest cost per email, AWS-grade reliability, and IP reputation that holds up under volume. Setup work is real, but every other API on this list pays SES wholesale rates somewhere upstream.

Top-tier deliverability, dedicated streams, fast delivery. Boring in the best way.

Strong SMTP relay, routing rules, and event stream. Late-2025 pricing change is a caveat.

Underrated. Independent tests place it near the top of inbox placement.

Improving deliverability and a dual testing-plus-sending product.

Clean SDKs across many languages, full message retention, predictable behavior.

API and SDKs are straightforward and the unified product reduces tool sprawl.

Modern API, clean dashboard, drag-and-drop plus code.

Best React Email experience but skewed toward React stacks; missing idempotency until recently.

Best-in-class staging plus production sending; SDK quality is solid.

AWS-grade infrastructure, regional reputation pools, and the volume that keeps shared IPs warm. The default backbone for high-deliverability transactional sending once configured and warmed.

Consistently in the top tier across independent tests. Stream separation keeps transactional reputation insulated from broadcast.

Twilio-backed, broad ecosystem, and dedicated IP options that let high-volume senders manage their own reputation. Shared pool varies, dedicated pool performs.

Repeatedly recognized for top inbox placement.

Strong recent results.

$0.10 per 1,000 emails. Nothing else comes close at unit cost.

$0.35 per 1,000 in beta. Cheapest managed sender if deliverability holds up.

Tiered plans with full-feature parity at higher tiers.

Pay-as-you-go SMTP credits publish a 1M-email tier below many managed senders.

Low entry pricing and API volume tiers make it a budget option when its feature set fits.

Cheapest unit cost by far. Regional reputation pools, IAM auth, and native Lambda/SNS/EventBridge wiring make it the default for high-volume senders already on AWS.

Built for enterprise high-volume senders with deep deliverability analytics.

Volume tiers competitive at scale; routing rules are useful for sharding.

Reasonable at high volume but feature-gated to higher SKUs.

Underrated at scale; full-feature parity across tiers keeps the bill predictable.

2,500 subscribers and 15,000 emails/mo on a permanent free plan. Strongest free marketing tier in this set.

12,000 transactional SMTP emails/mo is unusually generous, though the free plan is hourly capped.

6,000/mo capped at 200/day. Permanent and useful for steady low-volume sends.

Unlimited emails on the Free plan within a 1,000-contact ceiling. Different model: optimal when your contact list grows slowly but your volume is high.

300/day permanent. Best for low daily volumes that do not spike on launch day.

For teams that valued SendGrid as transactional only.

Closest API ergonomics if you used the SMTP plus API combo.

For volume-heavy senders with AWS infrastructure.

Testing plus sending with a generous free tier.

If you used SendGrid for marketing as well as transactional.

Closest to SES on pricing predictability, with deliverability and a real dashboard.

Volume tiers competitive at scale and proper webhooks out of the box.

Low-cost API and SMTP relay with webhooks, inbound, and subaccounts.

Generous free SMTP tier and pay-as-you-go credits make it a practical low-cost alternative.

Strong fit for teams leaving SES for analytics and a managed product.