The Canyon ReviewEmail APIs, ranked by deliverability per dollar
SES, Postmark, Resend and Mailgun ranked for transactional email. What you pay per thousand sends and what lands in inboxes.
Postmark if inbox placement pays your bills, SES if volume does, and Resend if developer experience is the tiebreaker. Mailgun is fine and that's the review. For once, this category's verdict is genuinely workload-shaped rather than one-size.
Scope: transactional mail (receipts, resets, alerts). Marketing blasts are a different product with different reputation math; mixing the two streams on one domain is the classic self-inflicted wound, whatever provider you pick.
Criteria: price per 10k and 100k sends 35%, deliverability reputation and tooling 35%, API and template ergonomics 20%, analytics honesty 10%. List prices as of April 2026.
The table
| Rank | Provider | 10k/mo | 100k/mo | Character |
|---|---|---|---|---|
| 1 | Postmark | ~$15 | ~$115 | deliverability zealots, in a good way |
| 2 | Amazon SES | ~$1 | ~$10 | raw sending at cost |
| 3 | Resend | ~$20 | ~$90 | the modern DX pick |
| 4 | Mailgun | ~$15 | ~$90 | competent, unremarkable |
The two honest strategies
Strategy one: pay Postmark to care. Separate message streams by default, aggressive list hygiene, and support humans who read bounce logs. When a password-reset email absolutely must arrive, the ~10x premium over SES prices out to fractions of a cent per send. Most businesses should just pay it.
Strategy two: SES at a dollar per ten thousand, and own the reputation work yourself. Dedicated IP warmup, DMARC alignment, bounce and complaint webhooks wired to actual list removal. Done well, SES deliverability is excellent; done lazily, you'll be googling "gmail promotions tab" by month two. The pricing page is the cheapest number in this market and it is not lying; it's just not the whole job.
Resend earned its rank by making email feel like a 2020s product: React email templates, an API you can hold in your head, webhooks that make sense. At small scale the premium over SES is noise; at 100k+ sends, do the math on what the ergonomics are worth.
The skip
Nothing here is a skip on quality, so the skip is a practice: sending marketing and transactional mail through one stream because the provider technically allows it. One promotional campaign's spam complaints can drag down the reset emails' reputation, and no provider's support team can un-ring that bell. Separate streams, separate subdomains, whichever row of the table you buy.