Quick answer
Postmark - Postmark wins for most builders who want a low-friction free tier, because it has no card requirement and a simpler path from tiny testing volume to paid sending, while Resend is better only if you need more free monthly sends and richer developer features right away.
How the free tiers compare
These two free tiers solve different problems. Postmark is the smaller, cleaner starter: 100 emails per month, no overages, no card required, and a free tier that never expires. It is best when you want to test deliverability or send a tiny amount of transactional email without worrying about daily caps or billing surprises. Resend gives you much more room on the free plan, with 3,000 emails per month, 100/day, plus SDKs, SMTP, REST, scheduling, batch sending, tracking, and automation runs. The tradeoff is that the free tier is more constrained in daily behavior and requires a card to start. After free, Postmark’s entry paid plan is slightly cheaper and its per-1,000 overage rate is lower at the top end, while Resend’s paid plan includes more app-oriented features and a much bigger included quota.
Postmark vs Resend free tier, side by side
| PostmarkFTV 44 | ResendFTV 30 | |
|---|---|---|
| Free monthly emailsResend also adds a 100 emails/day limit. | 100 emails/month | 3,000 emails/month |
| Free daily limitOnly Resend provides a daily cap in the input. | Not stated | 100 emails/day |
| Custom domains on free planPostmark’s free-tier domain allowance was not provided. | Not stated | 1 custom domain |
| Data retention on free planPostmark’s free-tier retention was not provided. | Not stated | 30 days |
| API and sending access on free planPostmark also mentions inbound email processing in the product description, but not in the free-tier items. | Email API and SMTP | REST API, SMTP relay, official SDKs |
After you outgrow the free tier
Both products use usage-based paid tiers, but the shape differs. Postmark starts at $15/mo for 10,000 emails with overages from $1.80 per 1,000 on Basic, then $16.50/mo and $18/mo tiers with lower overage rates and more domain/data features. Resend starts at $20/mo for 50,000 emails with overages at $0.90 per 1,000, then $90/mo for 100,000 emails, with Enterprise as custom pricing. For small teams sending beyond the free tier, Resend is usually cheaper on raw send volume, while Postmark is cheaper at the first paid entry point and may fit lower-volume transactional use better.
Cost at real usage
| Usage | Postmark | Resend |
|---|---|---|
| 10,000 emails/moPostmark’s Basic tier includes 10,000 starting emails; Resend’s Pro tier includes 50,000. | $15/mo | ~$20/mo |
| 50,000 emails/moPostmark Basic at $15 plus 40k extra at $1.80/1,000. Resend Pro includes 50k. | ~$87/mo est. | $20/mo |
| 100,000 emails/moPostmark Basic at $15 plus 90k extra at $1.80/1,000. Resend Scale includes 100k. | ~$177/mo est. | $90/mo |
Estimates, not quotes. Usage-based rates change - verify with the vendor's pricing page before committing.
When to pick each one
Pick Postmark when…
- You are integrating email into a side project and only need a tiny monthly send volume.
- You want to test transactional email deliverability without adding a credit card.
- You prefer a free plan that never expires and does not allow surprise overages.
- You expect to stay near 100 emails per month and want the simplest possible setup.
Pick Resend when…
- You need a free plan that can handle thousands of emails per month.
- You want built-in REST, SMTP, SDKs, React Email, scheduled sends, and batch sending on day one.
- You are okay with a daily sending cap as long as the monthly quota is much larger.
- You are building email workflows that benefit from tracking, automation runs, and webhook support.
Bottom line
For the most common builder case, Postmark is the better free-tier choice if you want a no-card, never-expiring sandbox for low-volume transactional email. Resend is the better pick if you want more room to experiment for free and need a broader set of developer-oriented email features before paying. Once you do pay, Resend tends to win on raw send capacity per dollar, while Postmark stays attractive for smaller, simpler sending setups.
Read the full listings: Postmark and Resend. Scores use the FTV methodology at /ftv. Browse more head-to-heads on /compare, or see the top-ranked free tiers on /top.