Email API Free Tiers Compared: Resend, Brevo, Mailtrap, MailerSend, Postmark, Mailgun and SES
Every figure below was read from the vendor's own page on October 30, 2026. Where a page did not show a number, this page says "see their pricing page" instead of guessing. Free tiers change often, so recheck before you build on one.
The comparison
| Provider | Free offering | Limits shown on the page |
|---|---|---|
| Resend | Free plan, $0 | 3,000 emails a month, 100 a day, 3 domains, 30-day data retention. Its FAQ says there is no trial but a free-forever plan. |
| Brevo | Free plan | Up to 300 emails per day once Brevo approves your account for sending. All plans include the transactional REST API, SMTP and outbound webhooks. |
| Mailtrap | Free plan, $0 | 4,000 emails a month, 150 a day, 1 domain, 1 user, 3 days of email logs. |
| MailerSend | Free plan | 1 domain, 100 daily API requests, 1 template, 1-day activity data retention. The FAQ says 500 emails a month and asks for card details to prevent abuse. |
| Mailgun | Free plan, $0 | 100 emails a day, 1 custom sending domain, 2 API keys, 1 day of log retention. Its Foundation plan lists a free first month, then $35 a month for 50,000 emails. |
| Postmark | Free developer plan, $0 | 100 emails a month, no overages allowed. It never expires. |
| SendGrid | 60-day trial, $0 | 100 emails a day for 60 days, no credit card. |
| Amazon SES | AWS Free Tier credits | New AWS customers get up to $200 in credits applicable to SES, with a free plan for 6 months after account creation. There is no free-forever sending allowance in the pricing table. |
| AISend | 3-day trial | 500 emails, no card, 1 verified domain, 100 email validations. It is a trial, not a free-forever plan. |
Sources, all read on October 30, 2026: Resend pricing, Brevo pricing, Mailtrap pricing, MailerSend pricing, Postmark pricing, Mailgun pricing, SendGrid pricing and Amazon SES pricing.
Who each one fits
- Mailtrap lists the largest monthly free allowance among the plans that state one, 4,000 emails against Resend's 3,000, with 3 days of logs.
- Resend's free plan lists three domains and 30 days of data retention, against one domain on the Mailtrap, MailerSend and Mailgun free plans, with a 100-a-day cap. A good fit for a product that sends a trickle of transactional mail.
- Brevo's free plan counts per day, not per month, and Brevo must approve your account before you can send. It fits a team that also wants campaigns in the same account.
- Postmark's 100 emails a month is for testing an integration, not running a product. Pick it when you want Postmark's paid plans later.
- MailerSend's free plan is tightly capped on templates, domains and API requests, and its paid Starter plan unlocks more domains and retention.
- Mailgun's free plan is 100 a day with one domain and one day of logs, enough to prove an integration works.
- SendGrid's offer is time-limited, 60 days, so it suits evaluation more than permanent hobby use.
- Amazon SES is billed per email after credits, and is the lowest unit price on this page: its pricing page lists $0.10 per 1,000 outbound emails à la carte and $0.16 per 1,000 on the Essentials plan. You build the dashboard, suppression handling and webhooks yourself.
- AISend's trial is short, 3 days, and sending to anyone other than your own account email needs a verified domain of your own. It suits a team that wants to try a Resend-compatible API and then pay for a plan.
What a free tier usually hides
- A daily cap can bite before the monthly one: Resend's 3,000 a month works out to the same as its 100-a-day cap, so a burst of signups can hit it.
- Account approval: Brevo and MailerSend approve accounts before you can send.
- Domain count: one domain on the Mailtrap, MailerSend and Mailgun free plans, three on Resend.
- Log retention: 1 day on MailerSend and Mailgun free, 3 days on Mailtrap free, 30 days on Resend free. That matters the day you debug a missed email.
- Branding, support and feature gates beyond what a pricing page lists; read each vendor's plan table for the feature you need.
If you outgrow a free tier, the next step is a paid plan. Our email API pricing comparison covers the paid tiers.
AISend's 3-day trial is free: 500 emails, no card, one verified domain. Paid plans are charged when you subscribe. AISend is for transactional and consented mail, and sending to anyone other than your own account email requires a verified domain.
Frequently asked questions
Which email API has the biggest free tier?
As checked on October 30, 2026, Mailtrap's free plan lists 4,000 emails a month and Resend's lists 3,000 a month. Brevo's free plan is measured per day, up to 300 emails a day after account approval, and Brevo does not publish a monthly total.
Does Amazon SES have a free tier?
Not as a permanent monthly allowance in its pricing table. The page says new AWS customers receive up to $200 in AWS Free Tier credits, including for SES, with a free plan for 6 months after account creation.
Does AISend have a free plan?
No. AISend has a free 3-day trial with 500 emails, no card and one verified domain. Paid plans are charged when you subscribe.
Are free tiers enough for production?
Sometimes, for very low volume. Check the daily cap, domain count and log retention, because those usually bind before the monthly number does.
Sources
More guides
Try the AISend trial
3 days, 500 emails, no card. Paid plans are charged when you subscribe.