Free email API and SMTP relay tiers in 2026: limits, catches and upgrade costs

Editorial team · updated 24 September 2026 · facts checked 24 September 2026

Nine of the 13 transactional email providers in our catalog offer a free email API tier with no end date: Bird, Brevo, Mailgun, Mailjet, Mailtrap, Postmark, Resend, SendPulse and SMTP2GO. They allow 100 to 12,000 emails a month, and all but Postmark also cap the day or hour. Amazon SES, SendGrid, Infobip and Telnyx offer only credits or a trial.

We re-read every pricing page, limits page and help article cited here on 24 September 2026 and matched the numbers against our provider cards. Nobody on the editorial team opened an account or sent email, so what happens at each cap comes from the providers' own documentation. Domain records and Gmail and Yahoo sender rules are covered in our transactional email guide.

Free-forever email API and SMTP relay tiers

"Free forever" here means the vendor states no end date and asks for no payment. Rows are alphabetical; each allowance links to the page it comes from.

The monthly headline misleads more often than it helps. Resend's 3,000 a month is reachable only by sending about 100 every day, and a receipt sent to a buyer with a BCC to your own inbox uses two of them. Resend, Mailtrap and Postmark also count received email, so an inbound support address shares the quota with your password resets.

In the transactional email API rankings, the free tier is half of the pricing score, and its size counts: our methodology grades a free-forever plan on a log scale from 40% of the points at 100 emails a month to 100% at 10,000 (a daily-only cap is multiplied by 30), and a trial or credits earn 20%. Brevo and SendPulse come closest to the top of that scale; Postmark's 100 a month sits at the bottom.

Trials and credits: Amazon SES, SendGrid, Infobip and Telnyx

Two vendors contradict themselves. The SES FAQ still offers "up to 3,000 message charges for free each month for the first 12 months", while the SES pricing page lists only the credits. SendGrid's pricing page sells a 60-day trial, and the same page's FAQ still mentions 100 emails a day "on our free SMTP plan". We use the dated trial wording and count neither as free forever; ask the vendor before you plan around the older text.

The SES credit matters less than the SES sandbox. Until AWS grants production access, which is requested per Region, an account sends only to verified addresses, at most 200 messages per 24 hours. Infobip's trial also sends only to addresses verified at sign-up, and after 60 days you "cannot send traffic" without upgrading, per its trial page.

What happens when you hit the daily cap

This is the failure you see on launch day, and the providers handle it differently:

Size for your busiest day, not your average month. Say a Supabase app gets 300 sign-ups on launch day: that is 300 confirmation emails before any receipt or reset. On Bird Free the 51st fails, on Resend the 101st, on Mailtrap the 151st. Mailjet and SMTP2GO push the overflow to the next day's quota, and a confirmation link that arrives a day late can cost you the sign-up. SendPulse's 400 a day covers the count, but at 50 an hour a burst above 50 hits its hourly limit, and its pages don't say whether the rest wait or fail. Supabase Auth also has its own hourly cap in front of the provider; the fix is on our Supabase email rate limit page.

Catches before you use a free tier in production

Approval before the first send. Brevo lets you send "once we approve your account for sending". SendPulse sends only after moderators approve the SMTP profile, which "usually takes up to 24 hours". Postmark delivers only to domains you own until a manual review, under 24 hours on weekdays per its approval article. Resend says free accounts get production access at sign-up with no sandbox.

How the vendor frames the plan. SMTP2GO's Terms call free accounts "primarily for trial purposes and for sending low amounts of email" and allow a business at most 10 of them. Postmark pitches its free plan for testing and side projects, and Mailgun labels its free card "Test us out". The pages we read don't forbid production traffic, and the allowances match the framing: 100 to about 3,000 emails a month.

Branding. Brevo's Free-plan FAQ says emails "always include the Sent with Brevo sticker", removable on Starter with the Remove Brevo branding add-on or on Standard and up. Mailjet drops its footer logo from Essential ($19) up; its $9 Starter keeps it. The other seven pricing pages list no logo or footer on free plans.

Domain authentication. Plan on SPF and DKIM records for your own domain before real sending; Gmail and Yahoo expect them. SMTP2GO throttles an account to 25 emails an hour until a sender domain is verified, and Mailtrap puts each new domain through an automatic compliance check before it sends. Mailgun's sandbox domain reaches only 5 authorized recipients. Its pricing page includes 1 custom sending domain on Free, while its docs FAQ still says free accounts can't create one; check before you build on it.

Short logs. Free plans keep sending logs for 1 day at Mailgun, 3 days at Mailtrap, 5 days at SMTP2GO and 30 days at Resend. Store webhook events yourself if you need to prove a reset email left.

How to pick a free tier for a vibe-coded app

Four questions narrow the list:

1. What is your busiest day? Count confirmations, magic links, resets and receipts on launch day and compare that with the daily cap, not the monthly one.
2. Who sends: your code or Supabase Auth? Supabase Auth takes SMTP credentials, and all nine free-forever plans include an SMTP relay; Telnyx lists none. Our Lovable and Supabase tutorial shows both paths. If your code calls the provider's API from a server route, the Next.js and React Email tutorial keeps the provider in one swappable function.
3. Do you receive email too? At Resend, Mailtrap and Postmark, inbound mail eats the same quota.
4. Can your emails carry another company's logo? If not, rule out Brevo and Mailjet on Free.

If your AI coding tool will do the wiring, the AI readiness data lists which of these providers publish an MCP server, agent skills or an llms.txt file.

When you outgrow the free tier

None of the nine free plans offers paid overage on the pages we read: past the cap, mail queues or fails. Brevo, Mailgun, Mailjet, Mailtrap, Postmark, Resend and SMTP2GO state that their first paid plan drops the daily cap; Bird's pages don't say. List prices on 24 September 2026, USD, monthly billing, before tax:

Brevo's Starter includes fewer emails a month (5,000) than its free plan allows (up to 9,000); you pay to lose the 300-a-day cap. Postmark has nothing between 100 and 10,000. SMTP2GO's interactive price table shows $15, while the page's no-JavaScript fallback still shows $10. SendPulse prints prices in the visitor's currency, and the page we loaded showed euros, so its paid plans are on the SendPulse card with the capture date. Metered options skip plans entirely: SES Essentials costs $0.16 per 1,000 emails, the plan new SES accounts have started on since 21 July 2026, and Telnyx charges $0.30 per 1,000 up to 10,000 a month at beta rates. SendGrid's Essentials plan starts at $19.95. Scored prices at 10,000 and 100,000 emails a month are in the transactional email API rankings.

Related guides

• Transactional email guide: SPF, DKIM and DMARC, Gmail and Yahoo rules, provider prices at 10,000 emails
• Email API vs SMTP relay: which of the two connection types your app should use
• Email MCP servers: letting an AI agent send through Resend, SendGrid, Mailgun or Postmark
• Send email from Lovable and Supabase: custom SMTP for auth mail, an Edge Function for app mail
• Fix "email rate limit exceeded" in Supabase: the Auth cap that fires before any provider cap
• Send email from Next.js with React Email: one send function, any provider
• Best transactional email APIs, ranked
• All provider cards, each fact with its source and check date

About this guide

The PingMyUsers editorial team wrote this article under the rules on the methodology page; the directory is operated by Sensaria AG in Switzerland. We did not create accounts or send email. Providers appear alphabetically; none paid for placement or reviewed the text. Report an error to contact@sensaria.ch; corrections are dated and sourced.

Methodology

On 24 September 2026 we re-read each provider's pricing page and the limits, help, trial and terms pages listed under Sources, and compared every number with our provider cards, last checked 23 September 2026. Four help centers (Brevo, Mailgun, Mailjet, SMTP2GO) returned a bot check to plain page loads; we read the same articles through each help center's public article API. The 9,000 a month for Brevo is Brevo's own figure; Mailgun prints no monthly number. Section order follows 70 searches that GPT and Gemini ran for five phrasings of this question. Every card field carries a source, an evidence status and a check date.

Last updated

24 September 2026: first version. We re-check free tiers every six months, and sooner when a vendor changes its pricing page.

Frequently asked questions

Is there a completely free email API?

Yes. Bird, Brevo, Mailgun, Mailjet, Mailtrap, Postmark, Resend, SendPulse and SMTP2GO each offer a free plan with no end date, checked 24 September 2026. Each caps volume, and all but Postmark also cap the day or the hour.

Which free email API has the highest limit?

By monthly volume, SendPulse (12,000 a month, 400 a day, 50 an hour), then Brevo (300 a day, 9,000 a month) and Mailjet (6,000 a month, 200 a day). SendPulse and Brevo both review new accounts before the first send.

Can I use a free email API tier in production?

Resend states free accounts have production access from sign-up. SMTP2GO's Terms describe free accounts as mainly for trials and low volume, and Postmark and Mailgun pitch theirs for testing. The daily cap is usually what forces the upgrade.

Is there a free SMTP relay?

Yes. All nine free-forever plans above include SMTP relay alongside the API, from 100 emails a month (Postmark) to 12,000 (SendPulse). Telnyx, which has no free plan, documents no SMTP relay at all.

Does Amazon SES have a free tier?

Not a permanent one. New AWS customers get up to $200 in credits usable on SES, and a payment method is required. The SES FAQ still mentions 3,000 free message charges a month for 12 months, which the pricing page no longer lists. Nine Amazon SES alternatives keep a free plan with no end date.

Does SendGrid still have a free plan?

Its pricing page lists a 60-day free trial at 100 emails a day, no credit card needed. The same page's FAQ still mentions a "free SMTP plan" with no end date, so confirm with Twilio before relying on it, or compare the SendGrid alternatives that keep a free plan.

Do free email plans add branding to emails?

Brevo and Mailjet do. Brevo adds a "Sent with Brevo" sticker until you take Starter with its branding add-on or move to Standard; Mailjet keeps a footer logo up to its $9 Starter plan. The other free plans' pricing pages mention no branding.

Do I need a credit card for a free email API?

Not for most. Bird, Brevo, Mailgun, Mailjet, Mailtrap, Postmark, SendPulse and SMTP2GO state no card is needed; Resend doesn't say. Amazon SES requires a payment method even for the AWS free plan.