Transactional email API pricing
Transactional email covers receipts, password resets, alerts and agent notifications. The deciding factors are deliverability, free-tier volume, price per extra thousand emails and API ergonomics. The table shows the limits and prices we verified.
Prices verified on vendor pages for 4 of 7 providers below; the rest are marked unknown. Always confirm at checkout. Order: vendor discounts, then free tiers, then standard signups, A–Z. Affiliate status does not affect order.
Comparison table
| Provider | Offer | Published pricing (verified) | Free option |
|---|---|---|---|
| AgentMail | Free tier | unknown | Yes |
| Postmark | Free tier | Free Developer plan: 100 emails/mo forever; free trial / no credit card to start | Yes |
| Resend | Free tier | 3,000 transactional emails/mo on Free | Yes |
| MailKite | Standard signup | Free to start; Pro $5 first month then $20/mo; Scale $25 and Business $100 for month one (card required) (per mailkite.dev). | Not verified |
| Postmark | Standard signup | unknown | Not verified |
| SendPulse | Standard signup | SMTP: free Basic plan 12,000 emails/mo; Pro 100k emails $74.85/mo monthly ($59.88/mo annual); Enterprise 500k emails $274.85/mo ($219.88/mo annual); pay-as-you-go from $15 per 10,000 emails (per sendpulse.com/prices/smtp). | Yes |
| SMTP2GO | Standard signup | unknown | Not verified |
Pros and cons
Derived only from facts on the vendor pages we checked.
AgentMail
Pros:
- Free plan, trial or credits to test before paying
- No card required to start (per vendor page)
Cons:
- No verified public price in our records; you must check the vendor site
Postmark
Pros:
- Free plan, trial or credits to test before paying
- No card required to start (per vendor page)
- Usage-based billing, so idle months cost little or nothing
- Pricing is published, so you can budget before signing up
Cons:
- Limits and overage rates vary by plan; read them before committing
Resend
Pros:
- Free plan, trial or credits to test before paying
- Pricing is published, so you can budget before signing up
Cons:
- Limits and overage rates vary by plan; read them before committing
MailKite
Pros:
- Offers an MCP server or agent integration
- Pricing is published, so you can budget before signing up
Cons:
- Some plans or trials require a card
- Part of the offer is one-time or intro-only; check the ongoing price
Postmark
Pros:
- Free plan, trial or credits to test before paying
Cons:
- No verified public price in our records; you must check the vendor site
SendPulse
Pros:
- Free plan, trial or credits to test before paying
- Usage-based billing, so idle months cost little or nothing
- Pricing is published, so you can budget before signing up
Cons:
- Limits and overage rates vary by plan; read them before committing
SMTP2GO
Pros:
- None verified beyond the listing
Cons:
- No verified public price in our records; you must check the vendor site
How to choose
- Keep transactional and marketing mail on separate streams or domains so promotions do not hurt receipts.
- Check daily caps as well as monthly totals on free tiers.
- If an agent must receive replies, pick a service with inbound webhooks or real inboxes.
- Compare overage pricing at your expected volume, not just the entry plan.
FAQ
Which transactional email API has the biggest free tier?
Compare the verified monthly limits in the table; also note daily caps.
Can I use these for newsletters?
Most transactional services restrict bulk marketing. Use a marketing platform for newsletters.
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