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Transactional email API·Every send traced

Send email.Watch it land.

Most email APIs go quiet after the 200. smtpfast traces the whole pipeline: every send, bounce, open, and webhook, live, per email.

Start sendingRead the docs

3,000 emails/month free/no card required/guided DNS setup

<50ms

queue time

99.9%

delivery rate

$0.15

per 1k emails

3

api lines to send

REST, SMTP, or copy-paste

Integrate in minutes.

Plain HTTP from any stack, SMTP for older apps, and delivery events back through signed webhooks.

send-email.ts
Next.jsExpressHonoBun
1const email = await fetch("https://smtpfa.st/api/v1/emails", {
2 method: "POST",
3 headers: {
4 Authorization: "Bearer sf_live_xxxxxxxxx",
5 "Content-Type": "application/json",
6 },
7 body: JSON.stringify({
8 from: "[email protected]",
9 to: "[email protected]",
10 subject: "Your report is ready",
11 html: "<p>Open the dashboard to view it.</p>",
12 }),
13});
email.sentqueuedemail.deliveredacceptedemail.openedtracked
Read the docsView on GitHub

Everything downstream of send()

Built around the pipeline.

Sending is the easy part. The work is knowing what happened next, and fixing it when something breaks.

logs --tailstreaming

Live tail, in the browser

An SSE stream of your delivery events as they happen. No log shipping, no refresh button.

why it bounced

Diagnostics, not status codes

Every bounce carries its type, subtype, and the receiving server's words, next to the exact email that triggered it.

smtp://

SMTP bridge

Point legacy apps at smtpfast credentials and they send through the same pipeline, traced like every API call.

webhooks

Native Discord & Slack

HMAC-signed webhooks for every event, or pick the Discord/Slack format and get readable alerts with zero glue code.

broadcasts

Broadcasts & forms

Contact lists, segments, double-opt-in signup forms, and scheduled broadcasts on the same infrastructure.

mcp

Built for AI agents

A hosted MCP server, markdown docs, and a full OpenAPI spec. Your agent can read the docs and send the email.

From zero to inbox

Three steps to your first email.

01

Add your domain

Add DNS records for DKIM authentication. We guide you through every record and check them live.

02

Get your API key

Generate a key from the dashboard. One key, full access to the API and the SMTP bridge.

03

Start sending

One API call and your email is queued, sent, and traced. You watch the rest happen.

Start free, stay cheap

Simple, predictable pricing.

Start free. Pay as you grow. No surprises.

Free

For testing and side projects

$0forever
  • 3,000 emails/month
  • Up to 1,000 contacts
  • 2 contact segments
  • 2 broadcasts/month
  • 1 sending domain
  • Email logs
  • Basic analytics
  • Community support
Start Free

Starter

For small apps and side projects

$9/month
  • 10,000 emails/month
  • Up to 5,000 contacts
  • 10 contact segments
  • 10 broadcasts/month
  • 3 sending domains
  • Up to 3 team members
  • Webhooks
  • Detailed analytics
  • Data export
  • Email support
Get Starter
Most popular

Growth

For production apps

$19/month
  • 50,000 emails/month
  • Up to 25,000 contacts
  • 50 contact segments
  • 50 broadcasts/month
  • Unlimited domains
  • Up to 10 team members
  • Webhooks
  • Open & click tracking
  • Live event tail (real-time logs)
  • Detailed analytics
  • Priority support
  • Data export
Get Growth

Scale

For high-volume senders

$49/month
  • 200,000 emails/month
  • Up to 100,000 contacts
  • 200 contact segments
  • 200 broadcasts/month
  • Up to 25 team members
  • Everything in Growth
  • Priority queue
  • Dedicated support
  • 99.9% uptime SLA
Get Scale
Optional overflow pricing

Need more emails without changing plans?

Upgrade first when you need more features. If you only need extra volume for a spike, active accounts can buy prepaid email credits at $0.001 per extra email.

Credit rate

$1

= 1,000 extra emails

See pricing

FAQ

Questions, answered

What is SMTPfast?
SMTPfast is a transactional email API for developers, built on AWS SES. You verify a domain, grab an API key, and send email over a REST API or SMTP, with real-time tracing of every send, bounce, open, and webhook per email.
Is SMTPfast a Resend alternative?
Yes. SMTPfast has a Resend-compatible sending API, so migrating is close to a base-URL and key swap, plus broadcasts, contact forms, an SMTP bridge, and deeper SES-backed deliverability tooling on top.
How much does SMTPfast cost?
There is a free tier with 3,000 emails per month. Paid plans start at $9/month for 10,000 emails, and you can add pay-as-you-go credits at $0.001 per extra email. No credit card is required to start.
Does SMTPfast support SMTP as well as a REST API?
Both. You can send over the JSON REST API or point any existing SMTP client at the SMTPfast SMTP bridge using your API key as the password, so legacy apps work without code changes.
Can AI agents and tools integrate with SMTPfast?
Yes. SMTPfast ships a hosted MCP server, a full OpenAPI spec, Markdown versions of every doc, and a Claude Skill, so AI coding agents can read the API and send email without hand-written glue.

Your next email,traced end to end.

Set up in under 5 minutes. 3,000 free emails every month. No credit card required.

Start sending

free tier forever/cancel anytime/your data stays yours