Transactional Email API Cost Comparison
Enter one monthly volume (presets 10k to 5M) and average message size. The table prices it on Amazon SES à la carte and Essentials, Resend (auto or chosen tier), Mailgun Auto (cheapest of Basic / Foundation / Scale) and Postmark Basic, Pro and Platform, with an optional dedicated IP and a winner callout. Estimates only; provider pricing pages prevail.
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| Option | Monthly | $ / 1k emails | Note |
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Same monthly volume priced on Amazon SES à la carte ($0.10/1k + $0.12/GB data), SES Essentials (tiered $0.16/1k + data), Resend (auto cheapest paid plan, or pick a Pro/Scale tier), Mailgun Auto (cheapest of Basic $15/10k, Foundation $35/50k, Scale $90/100k with listed overage) and Postmark Basic ($15 incl 10k, $1.80/1k), Pro ($16.50, $1.30/1k) and Platform ($18, $1.20/1k). Worked example: 30k emails → SES à la carte ≈ $3.12, Resend Pro $20, Mailgun Auto → Foundation $35, Postmark Basic $51 / Pro $42.50 / Platform $42. Mailgun is now listed; SendGrid and Brevo are still skipped because their official pages were not cleanly re-readable. Deep-dive: Mailgun calculator · Postmark calculator.
Estimates only. Official list prices as of 2026-11-04 (Asia/Shanghai); the provider's pricing page prevails. Sources: Amazon SES pricing · Resend pricing · Mailgun pricing · Postmark pricing
Mailgun Cost Calculator · Postmark Cost Calculator · Amazon SES Cost Calculator · Resend Cost Calculator · AI Agent Cost Calculator
More in this group
- Mailgun Cost Calculator Mailgun emails → plan, overage, validations and monthly $.
- Postmark Cost Calculator Postmark emails → cheapest plan, overage and monthly $.
- Amazon SES Cost Calculator Amazon SES emails × size → monthly cost and $/1k.
- Resend Cost Calculator Resend emails → cheapest plan, overage and monthly cost.
- AI Agent Cost Calculator Multi-step agent token cost per task and month.
- AI Subscription Cost Calculator Stack AI plans, seats, monthly or yearly USD.
- LLM API Cost Calculator Generic token cost from any $/1M rates.
How it works
- Which transactional email API is cheapest?
- At most volumes Amazon SES à la carte ($0.10 per 1k + $0.12/GB data) is cheapest. Example at 30k: SES ≈ $3.12, Resend Pro $20, Mailgun Auto → Foundation $35, Postmark Platform $42 / Pro $42.50 / Basic $51 (as of 2026-11-04).
- Why is SES Essentials more expensive than à la carte?
- Essentials ($0.16 per 1k) bundles plan features on top of sending; à la carte ($0.10 per 1k) is raw sending, with add-ons such as VDM or dedicated IPs billed separately.
- How does Mailgun Auto work here?
- Mailgun Auto picks the cheapest of Basic ($15/10k, $1.80/1k), Foundation ($35/50k, $1.30/1k) and Scale ($90/100k, $1.10/1k) for the entered volume. Open the Mailgun calculator for validations and dedicated IPs.
- Why are SendGrid and Brevo still missing?
- Mailgun is now listed (re-verified 2026-11-04). SendGrid and Brevo are still skipped because their official pricing pages were not cleanly re-readable (SendGrid entry-tier volumes stay undisclosed behind Twilio redirect).
- Does message size matter?
- Only for Amazon SES, which bills $0.12 per GB of message data. Resend, Mailgun and Postmark price per email regardless of size in this comparison.