Best Free Email API Vendor

Choosing a free email API takes more than comparing monthly allowances. You also need to look at daily sending limits to determine whether it can handle your traffic. Delivery logs are important on free plans to help diagnose failures. And you still need to keep in mind that the paid plans determine what growth will cost.

Mailfully is our recommendation for developers adding transactional email to an application. It offers 5,000 free emails a month—the largest ongoing allowance in this comparison. The daily plan limit is 200 emails. The free plan includes three sending domains and 30 days of delivery logs. Paid plans start at $19 a month for 50,000 emails.

The free plans at a glance

Prices were checked on September 22, 2026. All prices are in USD with monthly billing. The table distinguishes ongoing free plans from trials and temporary credits.

Mailfully: our first choice

Mailfully includes 5,000 free emails a month with a daily plan limit of 200 recipients. The free plan supports three sending domains and retains delivery logs for 30 days. Paid plans start at $19 a month for 50,000 emails. Additional sends cost $0.40 per 1,000 on every paid tier.

Its free allowance is the largest in this comparison. Logs include SMTP conversation details to help investigate delivery failures. Lower sending limits apply during account review. The free plan stops at its allowance without charging overages.

Resend: the closest alternative

Resend includes 3,000 emails a month. The free plan supports three domains and retains data for 30 days. Its React Email integration is a good fit if your team already builds templates with React. Pro costs $20 a month for 50,000 emails. Additional sends cost $0.90 per 1,000.

The free plan allows 100 emails a day regardless of the remaining monthly allowance.

Mailgun: 100 emails a day, one day of logs

Mailgun's free plan allows 100 emails a day and retains logs for one day. Basic starts at $15 a month for 10,000 emails. It removes the daily sending limit but keeps the same log retention period.

Investigating older messages requires a separate record such as an archive of webhook events.

MailerSend: a smaller free allowance, paid plans from $7

MailerSend offers 500 free emails a month after account approval. Its help center lists a daily limit of 100 emails. Its pricing page also specifies 100 daily API requests. Status checks consume requests too. An integration can therefore reach the request limit before exhausting its sending allowance.

Hobby costs $7 a month for 5,000 emails. It is the least expensive paid subscription in this comparison. It may suit applications that need paid features at low volume.

Postmark: a free plan for testing or very low volume

Postmark's free plan includes 100 emails a month. It does not expire and permits no overages. Messages are retained for 45 days. Paid plans start at $15 a month for 10,000 emails.

The free allowance suits testing and applications with minimal email traffic. Even four emails a day exceed it over a 30-day month.

SendGrid: a 60-day free trial

SendGrid began retiring its ongoing free plan in May 2025. Existing free accounts received a 60-day transition period. The current offer is a 60-day trial allowing 100 emails a day. Essentials starts at $19.95 a month.

Continued sending requires a paid plan once the trial ends.

Amazon SES: low sending costs, temporary free credits

Amazon SES offers eligible new AWS customers temporary credits rather than an ongoing monthly free allowance. Its à la carte outbound sending rate is $0.10 per 1,000 emails. New SES accounts default to Essentials at a starting rate of $0.16 per 1,000. AWS allows switching to à la carte pricing. Data and optional services can add charges.

SES suits teams that prioritize low sending costs and have the capacity to configure and maintain the supporting AWS services. The à la carte sending charge for 50,000 outbound emails is $5 before other charges.

Start with Mailfully

Mailfully is our first choice for a free transactional email API. It has the largest ongoing free allowance in this comparison and retains delivery logs for 30 days. The $19 paid plan increases monthly capacity to 50,000 emails.